https://hallaweb.jlab.org/wiki/api.php?action=feedcontributions&user=Melissac&feedformat=atomHall A Wiki - User contributions [en]2021-05-18T20:21:10ZUser contributionsMediaWiki 1.26.0https://hallaweb.jlab.org/wiki/index.php?title=G2p&diff=28765G2p2016-04-11T00:23:58Z<p>Melissac: /* g2p Theses */</p>
<hr />
<div>==The Experiments==<br />
<B>E08-027</B> will measure the proton spin structure function g2p in Jefferson Lab's Hall A.<br />
*Spokesmen: A. Camsonne, J.P. Chen, D. Crabb and K. Slifer (contact). <br />
*Full details of the physics goals are provided in the [http://hallaweb.jlab.org/experiment/g2p/docs/PAC33/dlt.pdf proposal]<br />
*The g2p [http://hallaweb.jlab.org/experiment/g2p/ website].<br />
<br />
<B>E08-007</B> will measure the proton spin structure function ratio GE/GM <br />
*Spokesmen: R. Gilman, D. Higinbotham, G. Ron (contact), J. Arrington, D. Day, A. Sarty.<br />
*The GEP [http://hallaweb.jlab.org/experiment/E08-007/ website].<br />
<br />
==Runplan and Schedule==<br />
*Today's [http://hallaweb.jlab.org/experiment/g2p/shifts/today runplan] <br />
*The [https://misportal.jlab.org/mis/physics/shiftschedule/index.cfm?experimentRunId=G2PGEP shift schedule]<br />
*The longterm g2p production [http://hallaweb.jlab.org/experiment/g2p/project/rates_2012-02-09.pdf plan] <br />
*The experiment schedule: [http://hallaweb.jlab.org/experiment/g2p/project/g2p_production_20120417.pdf (pdf)]<br />
*The accelerator schedule: [http://hallaweb.jlab.org/experiment/g2p/project/schedule_as_20120330_web.pdf (pdf)]<br />
<br />
==Shift Worker Information==<br />
*Shift Worker [https://hallaweb.jlab.org/wiki/index.php/G2p_shifts Instructions]<br />
*Expert Shift Worker [https://hallaweb.jlab.org/wiki/index.php/g2p_Expert_Shifts Instructions]<br />
*g2p Safety [https://hallaweb.jlab.org/wiki/index.php/G2p_documentation documentation]<br />
<br />
==DAQ==<br />
*The g2p [https://hallaweb.jlab.org/wiki/index.php/G2pdaq DAQ Guide]<br />
<br />
==Beamline==<br />
*[[g2p BCM calibration]]<br />
*[[g2p BPM calibration]]<br />
*[[g2p Beampackage]]<br />
*[[g2p Helicity Decoder]]<br />
<br />
==Analysis==<br />
*The g2p [https://hallaweb.jlab.org/wiki/index.php/G2pAnalysis Analysis Guide]<br />
<br />
* Scanned Run [https://hallaweb.jlab.org/wiki/index.php/G2pRunSheets Sheets]<br />
<br />
* Scanned Back Room Run [https://hallaweb.jlab.org/wiki/index.php/G2pBackRoomRunSheets Sheets]<br />
<br />
* Scanned Shift [https://hallaweb.jlab.org/wiki/index.php/G2pShiftChecklists Checklists]<br />
<br />
*Run [https://hallaweb.jlab.org/wiki/index.php/G2pRunSummaries Summaries]<br />
<br />
*Summary of runs for different [https://hallaweb.jlab.org/wiki/images/2/2c/Energy_summary.pdf energy] settings<br />
<br />
*g2p [https://hallaweb.jlab.org/wiki/index.php/G2pmysql mysql]<br />
<br />
*g2p [http://hallaweb.jlab.org/experiment/g2p/meetings/051812/talks/g2p_tasks_2012_0518.pdf task list]<br />
<br />
*g2p [https://hallaweb.jlab.org/wiki/index.php/G2p/analyzerdb Analyzer DB]<br />
<br />
*Beam polarization measured by [http://hallaweb.jlab.org/equipment/moller/e08-027.html Moller]<br />
<br />
*[https://hallaweb.jlab.org/wiki/index.php/G2p_data_quality Data quality check]<br />
<br />
==Polarized Target==<br />
*[[Solid Polarized Target]]<br />
<br />
==Survey Results==<br />
*[http://hallaweb.jlab.org/experiment/g2p/survey/ g2p survey page]<br />
<br />
==Spectrometer Optics==<br />
*[https://hallaweb.jlab.org/wiki/index.php?title=G2p_optics g2p optics page]<br />
<br />
==Weekly Meetings==<br />
*Analysis Meetings are held every Weds at 10:30. ([https://hallaweb.jlab.org/wiki/index.php/G2p_Analysis_Minutes minutes]) ([https://hallaweb.jlab.org/wiki/index.php/G2p_Weekly_Analysis Agendas])<br />
*Past Target Meeting ([https://hallaweb.jlab.org/wiki/index.php/G2p_Target_Minutes minutes])<br />
*Beam Transport Meeting ([http://hallaweb.jlab.org/experiment/E08-027/meetings/beamline/ minutes])<br />
*Weekly Hall A meeting Run Coordinator ([https://hallaweb.jlab.org/wiki/index.php/G2pRC Reports])<br />
<br />
==Collaboration Meetings==<br />
*[[14th Nov, 2014]]<br />
*[http://hallaweb.jlab.org/experiment/g2p/meetings/051812/ May 18, 2012] (End of Run)<br />
*[https://hallaweb.jlab.org/wiki/index.php/G2p_Safety_Readiness_Review January 17, 2012 (JLab Safety/Readiness Review)]<br />
*[http://hallaweb.jlab.org/experiment/g2p/status/ August 30, 2011 (Hall A Review)]<br />
*[http://hallaweb.jlab.org/experiment/g2p/review/ May 6, 2011 (Readiness Review)] ([http://hallaweb.jlab.org/experiment/g2p/review/G2P_review_report.pdf Final Report])<br />
*[http://hallaweb.jlab.org/experiment/g2p/meetings/041811/ April 18, 2011] ([http://hallaweb.jlab.org/experiment/g2p/meetings/041811/talks/minutes_g2pcollab_041811.pdf minutes])<br />
*[http://hallaweb.jlab.org/experiment/g2p/meetings/020411/ Feb. 4, 2011]<br />
*[http://hallaweb.jlab.org/experiment/g2p/meetings/093010/index.html Sep. 30, 2010] ([http://hallaweb.jlab.org/experiment/g2p/meetings/093010/talks/093010_collab_notes.pdf minutes])<br />
<br />
==Technotes==<br />
*[https://hallaweb.jlab.org/wiki/index.php/G2p_technotes E08-027 Technical Documents]<br />
<br />
==Talks and Presentations==<br />
*2015 Chiral Dynamics Workshop, R. Zielinski ([https://userweb.jlab.org/~rbziel/JSTF-2015-Zielinski.pdf Talk]) <br />
*2014 Hall A Winter Collaboration Meeting, P. Zhu ([http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/g2p_gep.pdf g2p_gep analysis status]) <br />
*2014 APS/JPS Joint Meeting, T. Badman ([http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/talks/g2ptalk_dnp4.pdf Talk]) ([http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/talks/g2pabstract_dnp14.pdf Abstract])<br />
*2014 SPIN2014, M. Cummings ([http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/talks/MCummings_SPIN2014.pdf A Measurement of g2p at Low Q<sup>2</sup>])<br />
*2014 The Sixth Workshop on Hadron Physics in China and Opportunities in US, C. Gu ([http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/talks/HadronWorkshop_07222014.pdf The g2 Spin Structure Function])<br />
*2014 Gordon Research Conference, R. Zielinski ([http://nuclear.unh.edu/~ryan/Doc/GRC_Poster_final.pdf poster])<br />
*2014 Gordon Research Conference, T. Badman ([http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/talks/targetposter_grc14.pdf poster] [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/talks/targetabstract_grc14.pdf abstract])<br />
*2014 DIS2014, M. Cummings ([http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/talks/MCummings_DIS2014.pdf The g2 Spin Structure Function])<br />
*2013 Hall A & C Data Analysis Workshop, C. Gu ([http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/talks/AnalysisWorkshop_12182013.pdf Spectrometer Optics Calibration for g2p Experiment])<br />
*2013 Hall A Winter Collaboration Meeting, J. Liu ([http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/talks/jie_g2p_hall_A_collaboration_final.pdf g2p])<br />
*2013 Fall 2013 DNP Meeting, R. Zielinski ([https://userweb.jlab.org/~rbziel/DNP2013_v2.pdf Talk]) ([https://userweb.jlab.org/~rbziel/DNP_2013_Abstract_RZ.pdf Abstract])<br />
*2013 The Fifth Workshop on Hadron Physics in China and Opportunities in US, Jie Liu ([https://hep.ustc.edu.cn/indico/getFile.py/access?contribId=43&sessionId=2&resId=0&materialId=slides&confId=1 g2p])<br />
*2013 JLab Users Group Meeting, M. Cummings ([http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/posters/UsersGroupPoster.pdf poster])<br />
*2013 Hall A Summer Collaboration Meeting, M. Huang ([http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/Talks/g2p_minhuang_HallA2013summer.pdf g2p])<br />
*2013 APS April Meeting, M. Cummings ([http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/talks/APS2013_target.pdf Polarized Proton Target for the g2p Experiment])<br />
*2013 APS April Meeting, C. Gu ([http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/talks/APSAprilMeeting_04162013.pdf Spectrometer Optics Calibration for g2p Experiment])<br />
*2013 APS April Meeting, M. Huang ([http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/Talks/g2p_minhuang_APS2013April.pdf A Measurement of Proton g2 and the Longitudinal-transverse Spin Polarizability])<br />
*2013 Group on Hadronic Physics Workshop, Toby Badman ([http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/ghp2013.pdf The g2p Experiment])<br />
*2013 Few Slide overview, K. Slifer ([https://userweb.jlab.org/~slifer/g2p/talks/2013_g2p_summary.ppt ppt])<br />
*2012 Hall A & C Data Analysis Workshop, M. Huang ([http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/Talks/g2pOptics_MinHuang_hallA2012winter.pdf g2p HRS Optics with Septum])<br />
*2012 Hall A & C Data Analysis Workshop, Jixie Zhang ([http://hallaweb.jlab.org/data_reduc/AnaWork2012/Jixie_HRSMC_20121212.pdf HRSMC, The Geant4 Simulation of HRS for the G2P and GEP Experiments])<br />
*2012 Hall A Winter Collaboration Meeting, M. Cummings ([https://hallaweb.jlab.org/wiki/images/c/cb/Melissa_g2pUpdate_HallA.pdf Update on g2p])<br />
*2012 Gordon Conference (Poster section), Jixie Zhang ([http://hallaweb.jlab.org/experiment/g2p/collaborators/jixie/talks/G2PG4Sim_48X36_GRC_Jixie.pdf The Geant4 Simulation of G2P|GEP Experiments])<br />
*2012 Chiral Dynamics Workshop, P.Zhu ([https://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/08082012_ciral/CD12.pdf instrumentation for the g2p experiment])<br />
*2012 Chiral Dynamics Workshop, C. Gu ([https://hallaweb.jlab.org/experiment/g2p/collaborators/chao/talks/ChiralDynamicWorkshop_08082012.pdf pdf])<br />
*2012 Gordon Research Conference, T. Badman ([http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/talks/targetposter_grc12.pdf poster] [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/talks/targetabstract_grc12.pdf abstract])<br />
*2012 Gordon Research Conference, M. Cummings and R. Zielinski ([https://hallaweb.jlab.org/wiki/images/1/10/MelissaCummings_GRC-1.pdf poster] [https://hallaweb.jlab.org/wiki/images/b/b4/Poster_Abstract_5.pdf abstract])<br />
*2012 Summary Slides for Hall A, K. Slifer ([http://hallaweb.jlab.org/experiment/g2p/talks/2012_wrapup_2.ppt ppt])<br />
*2012 Hall A collaboration meeting, Jixie Zhang ([http://hallaweb.jlab.org/experiment/g2p/collaborators/jixie/talks/Jixie_g2p_HACol_2012.pdf G2P status update])<br />
*2012 Hall A collaboration meeting, R. Zielinski ([https://hallaweb.jlab.org/wiki/images/7/7e/HallA_DAQ.pdf DAQ])<br />
*2012 Hall A collaboration meeting, P.Zhu ([http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/06062012/beamline%20improvement.pdf beamline])<br />
*2012 JLab User Group Meeting, K. Slifer ([http://hallaweb.jlab.org/experiment/g2p/talks/slifer_g2p_ug12.ppt ppt])<br />
*2012 JLab Graduate Student Seminar, K. Slifer ([http://hallaweb.jlab.org/experiment/g2p/talks/Slifer_g2p_jlab.ppt.pdf pdf])<br />
*2011 Al Gavalya's [http://userweb.jlab.org/~slifer/g2p/figs/g2p_Hall.pdf overview of Hall A]<br />
*2011 NSTAR, K. Slifer ([http://conferences.jlab.org/nstar2011/Thursday%20NSTAR%20Plenary/Slifer_nstar11.ppt.pdf pdf])<br />
*2011 Hall A Workshop, K. Slifer ([http://hallaweb.jlab.org/collab/meeting/2011-summer/talks/day1/Slifer_g2p_hallAcollab_060911.ppt ppt])<br />
*2010 Hall A Collaboration Meeting, K. Allada ([https://userweb.jlab.org/~kalyan/g2p/meetings/HallACollab_Dec2010_Kalyan.pdf])<br />
*2010 One Slide Summary ([http://hallaweb.jlab.org/experiment/g2p/talks/2010_g2p_oneslide.ppt ppt])<br />
*2009 E08-027/E08-007 Presentation to R. McKeown ([http://hallaweb.jlab.org/experiment/g2p/talks/g2p_gep_combined.pdf pdf])<br />
<br />
==g2p Theses==<br />
*[http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Thesis/MCummings_Dissertation.pdf M. Cummings]<br />
<br />
==Relevent Theses==<br />
*[http://hallaweb.jlab.org/experiment/E97-110/thesis.html E97110 List]<br />
*[http://www.jlab.org/e94010/#Theses E94010 List]<br />
*[http://twist.phys.virginia.edu/~jdm2z/jdm_thesis.pdf J. Maxwell: SANE]<br />
<br />
==Relevent Publications==<br />
*New Insights into the spin structure of the nucleon. [http://prd.aps.org/abstract/PRD/v87/i5/e054032 Phys.Rev. D87 (2013) 054032]<br />
*Axial anomaly and the δLT puzzle. [http://prd.aps.org/abstract/PRD/v85/i1/e016012 Phys. Rev. D 85, 016012 (2012)]<br />
*M. J. Alguard, et al. Deep Inelastic Scattering of Polarized Electrons by Polarized Protons [http://prl.aps.org/abstract/PRL/v37/i19/p1261_1 PRL]<br />
*M. J. Alguard, et al. Elastic Scattering of Polarized Electrons by Polarized Protons [http://prl.aps.org/abstract/PRL/v37/i19/p1258_1 PRL]<br />
*Donnelly and Raskin, Considerations of Polarization in Inclusive Electron Scattering from Nuclei [http://hallaweb.jlab.org/experiment/g2p/papers/Donnelly.pdf pdf]<br />
*Proceedings of the 4th International Workshop on Polarized Target Materials and Techniques, Universitat Bonn [http://hallaweb.jlab.org/experiment/g2p/papers/GreenBook.pdf portrait] [http://hallaweb.jlab.org/experiment/g2p/papers/GreenBook_landscape.pdf landscape]<br />
*Proceedings from BadHonnef, 1995 [http://galileo.phys.virginia.edu/~dbd/BadHonnef1995.pdf pdf]<br />
<br />
==Links==<br />
*[http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/wiki/halog splitted halog]<br />
*[http://phys.huji.ac.il/~gron/ Ron Group] at Hebrew University of Jerusalem.<br />
*The JLab [http://www.jlab.org/exp_prog/experiment_schedule/ schedule] webpage <br />
*[http://clasweb.jlab.org/spin_rotation/ Spin Rotator] website<br />
<br />
==Mailing List==<br />
There are two mailing lists relevant to g2p:<br />
*g2p@jlab.org : General announcements<br />
*g2p_ana@jlab.org : Weekly analysis<br />
You can subscribe to both at http://mailman.jlab.org<br />
<br />
==Help==<br />
*[[Getting_Started_with_the_g2pWiki| HOW-TO]] use the g2pwiki.</div>Melissachttps://hallaweb.jlab.org/wiki/index.php?title=G2p&diff=28764G2p2016-04-11T00:23:17Z<p>Melissac: /* Relevent Theses */</p>
<hr />
<div>==The Experiments==<br />
<B>E08-027</B> will measure the proton spin structure function g2p in Jefferson Lab's Hall A.<br />
*Spokesmen: A. Camsonne, J.P. Chen, D. Crabb and K. Slifer (contact). <br />
*Full details of the physics goals are provided in the [http://hallaweb.jlab.org/experiment/g2p/docs/PAC33/dlt.pdf proposal]<br />
*The g2p [http://hallaweb.jlab.org/experiment/g2p/ website].<br />
<br />
<B>E08-007</B> will measure the proton spin structure function ratio GE/GM <br />
*Spokesmen: R. Gilman, D. Higinbotham, G. Ron (contact), J. Arrington, D. Day, A. Sarty.<br />
*The GEP [http://hallaweb.jlab.org/experiment/E08-007/ website].<br />
<br />
==Runplan and Schedule==<br />
*Today's [http://hallaweb.jlab.org/experiment/g2p/shifts/today runplan] <br />
*The [https://misportal.jlab.org/mis/physics/shiftschedule/index.cfm?experimentRunId=G2PGEP shift schedule]<br />
*The longterm g2p production [http://hallaweb.jlab.org/experiment/g2p/project/rates_2012-02-09.pdf plan] <br />
*The experiment schedule: [http://hallaweb.jlab.org/experiment/g2p/project/g2p_production_20120417.pdf (pdf)]<br />
*The accelerator schedule: [http://hallaweb.jlab.org/experiment/g2p/project/schedule_as_20120330_web.pdf (pdf)]<br />
<br />
==Shift Worker Information==<br />
*Shift Worker [https://hallaweb.jlab.org/wiki/index.php/G2p_shifts Instructions]<br />
*Expert Shift Worker [https://hallaweb.jlab.org/wiki/index.php/g2p_Expert_Shifts Instructions]<br />
*g2p Safety [https://hallaweb.jlab.org/wiki/index.php/G2p_documentation documentation]<br />
<br />
==DAQ==<br />
*The g2p [https://hallaweb.jlab.org/wiki/index.php/G2pdaq DAQ Guide]<br />
<br />
==Beamline==<br />
*[[g2p BCM calibration]]<br />
*[[g2p BPM calibration]]<br />
*[[g2p Beampackage]]<br />
*[[g2p Helicity Decoder]]<br />
<br />
==Analysis==<br />
*The g2p [https://hallaweb.jlab.org/wiki/index.php/G2pAnalysis Analysis Guide]<br />
<br />
* Scanned Run [https://hallaweb.jlab.org/wiki/index.php/G2pRunSheets Sheets]<br />
<br />
* Scanned Back Room Run [https://hallaweb.jlab.org/wiki/index.php/G2pBackRoomRunSheets Sheets]<br />
<br />
* Scanned Shift [https://hallaweb.jlab.org/wiki/index.php/G2pShiftChecklists Checklists]<br />
<br />
*Run [https://hallaweb.jlab.org/wiki/index.php/G2pRunSummaries Summaries]<br />
<br />
*Summary of runs for different [https://hallaweb.jlab.org/wiki/images/2/2c/Energy_summary.pdf energy] settings<br />
<br />
*g2p [https://hallaweb.jlab.org/wiki/index.php/G2pmysql mysql]<br />
<br />
*g2p [http://hallaweb.jlab.org/experiment/g2p/meetings/051812/talks/g2p_tasks_2012_0518.pdf task list]<br />
<br />
*g2p [https://hallaweb.jlab.org/wiki/index.php/G2p/analyzerdb Analyzer DB]<br />
<br />
*Beam polarization measured by [http://hallaweb.jlab.org/equipment/moller/e08-027.html Moller]<br />
<br />
*[https://hallaweb.jlab.org/wiki/index.php/G2p_data_quality Data quality check]<br />
<br />
==Polarized Target==<br />
*[[Solid Polarized Target]]<br />
<br />
==Survey Results==<br />
*[http://hallaweb.jlab.org/experiment/g2p/survey/ g2p survey page]<br />
<br />
==Spectrometer Optics==<br />
*[https://hallaweb.jlab.org/wiki/index.php?title=G2p_optics g2p optics page]<br />
<br />
==Weekly Meetings==<br />
*Analysis Meetings are held every Weds at 10:30. ([https://hallaweb.jlab.org/wiki/index.php/G2p_Analysis_Minutes minutes]) ([https://hallaweb.jlab.org/wiki/index.php/G2p_Weekly_Analysis Agendas])<br />
*Past Target Meeting ([https://hallaweb.jlab.org/wiki/index.php/G2p_Target_Minutes minutes])<br />
*Beam Transport Meeting ([http://hallaweb.jlab.org/experiment/E08-027/meetings/beamline/ minutes])<br />
*Weekly Hall A meeting Run Coordinator ([https://hallaweb.jlab.org/wiki/index.php/G2pRC Reports])<br />
<br />
==Collaboration Meetings==<br />
*[[14th Nov, 2014]]<br />
*[http://hallaweb.jlab.org/experiment/g2p/meetings/051812/ May 18, 2012] (End of Run)<br />
*[https://hallaweb.jlab.org/wiki/index.php/G2p_Safety_Readiness_Review January 17, 2012 (JLab Safety/Readiness Review)]<br />
*[http://hallaweb.jlab.org/experiment/g2p/status/ August 30, 2011 (Hall A Review)]<br />
*[http://hallaweb.jlab.org/experiment/g2p/review/ May 6, 2011 (Readiness Review)] ([http://hallaweb.jlab.org/experiment/g2p/review/G2P_review_report.pdf Final Report])<br />
*[http://hallaweb.jlab.org/experiment/g2p/meetings/041811/ April 18, 2011] ([http://hallaweb.jlab.org/experiment/g2p/meetings/041811/talks/minutes_g2pcollab_041811.pdf minutes])<br />
*[http://hallaweb.jlab.org/experiment/g2p/meetings/020411/ Feb. 4, 2011]<br />
*[http://hallaweb.jlab.org/experiment/g2p/meetings/093010/index.html Sep. 30, 2010] ([http://hallaweb.jlab.org/experiment/g2p/meetings/093010/talks/093010_collab_notes.pdf minutes])<br />
<br />
==Technotes==<br />
*[https://hallaweb.jlab.org/wiki/index.php/G2p_technotes E08-027 Technical Documents]<br />
<br />
==Talks and Presentations==<br />
*2015 Chiral Dynamics Workshop, R. Zielinski ([https://userweb.jlab.org/~rbziel/JSTF-2015-Zielinski.pdf Talk]) <br />
*2014 Hall A Winter Collaboration Meeting, P. Zhu ([http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/g2p_gep.pdf g2p_gep analysis status]) <br />
*2014 APS/JPS Joint Meeting, T. Badman ([http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/talks/g2ptalk_dnp4.pdf Talk]) ([http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/talks/g2pabstract_dnp14.pdf Abstract])<br />
*2014 SPIN2014, M. Cummings ([http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/talks/MCummings_SPIN2014.pdf A Measurement of g2p at Low Q<sup>2</sup>])<br />
*2014 The Sixth Workshop on Hadron Physics in China and Opportunities in US, C. Gu ([http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/talks/HadronWorkshop_07222014.pdf The g2 Spin Structure Function])<br />
*2014 Gordon Research Conference, R. Zielinski ([http://nuclear.unh.edu/~ryan/Doc/GRC_Poster_final.pdf poster])<br />
*2014 Gordon Research Conference, T. Badman ([http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/talks/targetposter_grc14.pdf poster] [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/talks/targetabstract_grc14.pdf abstract])<br />
*2014 DIS2014, M. Cummings ([http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/talks/MCummings_DIS2014.pdf The g2 Spin Structure Function])<br />
*2013 Hall A & C Data Analysis Workshop, C. Gu ([http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/talks/AnalysisWorkshop_12182013.pdf Spectrometer Optics Calibration for g2p Experiment])<br />
*2013 Hall A Winter Collaboration Meeting, J. Liu ([http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/talks/jie_g2p_hall_A_collaboration_final.pdf g2p])<br />
*2013 Fall 2013 DNP Meeting, R. Zielinski ([https://userweb.jlab.org/~rbziel/DNP2013_v2.pdf Talk]) ([https://userweb.jlab.org/~rbziel/DNP_2013_Abstract_RZ.pdf Abstract])<br />
*2013 The Fifth Workshop on Hadron Physics in China and Opportunities in US, Jie Liu ([https://hep.ustc.edu.cn/indico/getFile.py/access?contribId=43&sessionId=2&resId=0&materialId=slides&confId=1 g2p])<br />
*2013 JLab Users Group Meeting, M. Cummings ([http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/posters/UsersGroupPoster.pdf poster])<br />
*2013 Hall A Summer Collaboration Meeting, M. Huang ([http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/Talks/g2p_minhuang_HallA2013summer.pdf g2p])<br />
*2013 APS April Meeting, M. Cummings ([http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/talks/APS2013_target.pdf Polarized Proton Target for the g2p Experiment])<br />
*2013 APS April Meeting, C. Gu ([http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/talks/APSAprilMeeting_04162013.pdf Spectrometer Optics Calibration for g2p Experiment])<br />
*2013 APS April Meeting, M. Huang ([http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/Talks/g2p_minhuang_APS2013April.pdf A Measurement of Proton g2 and the Longitudinal-transverse Spin Polarizability])<br />
*2013 Group on Hadronic Physics Workshop, Toby Badman ([http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/ghp2013.pdf The g2p Experiment])<br />
*2013 Few Slide overview, K. Slifer ([https://userweb.jlab.org/~slifer/g2p/talks/2013_g2p_summary.ppt ppt])<br />
*2012 Hall A & C Data Analysis Workshop, M. Huang ([http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/Talks/g2pOptics_MinHuang_hallA2012winter.pdf g2p HRS Optics with Septum])<br />
*2012 Hall A & C Data Analysis Workshop, Jixie Zhang ([http://hallaweb.jlab.org/data_reduc/AnaWork2012/Jixie_HRSMC_20121212.pdf HRSMC, The Geant4 Simulation of HRS for the G2P and GEP Experiments])<br />
*2012 Hall A Winter Collaboration Meeting, M. Cummings ([https://hallaweb.jlab.org/wiki/images/c/cb/Melissa_g2pUpdate_HallA.pdf Update on g2p])<br />
*2012 Gordon Conference (Poster section), Jixie Zhang ([http://hallaweb.jlab.org/experiment/g2p/collaborators/jixie/talks/G2PG4Sim_48X36_GRC_Jixie.pdf The Geant4 Simulation of G2P|GEP Experiments])<br />
*2012 Chiral Dynamics Workshop, P.Zhu ([https://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/08082012_ciral/CD12.pdf instrumentation for the g2p experiment])<br />
*2012 Chiral Dynamics Workshop, C. Gu ([https://hallaweb.jlab.org/experiment/g2p/collaborators/chao/talks/ChiralDynamicWorkshop_08082012.pdf pdf])<br />
*2012 Gordon Research Conference, T. Badman ([http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/talks/targetposter_grc12.pdf poster] [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/talks/targetabstract_grc12.pdf abstract])<br />
*2012 Gordon Research Conference, M. Cummings and R. Zielinski ([https://hallaweb.jlab.org/wiki/images/1/10/MelissaCummings_GRC-1.pdf poster] [https://hallaweb.jlab.org/wiki/images/b/b4/Poster_Abstract_5.pdf abstract])<br />
*2012 Summary Slides for Hall A, K. Slifer ([http://hallaweb.jlab.org/experiment/g2p/talks/2012_wrapup_2.ppt ppt])<br />
*2012 Hall A collaboration meeting, Jixie Zhang ([http://hallaweb.jlab.org/experiment/g2p/collaborators/jixie/talks/Jixie_g2p_HACol_2012.pdf G2P status update])<br />
*2012 Hall A collaboration meeting, R. Zielinski ([https://hallaweb.jlab.org/wiki/images/7/7e/HallA_DAQ.pdf DAQ])<br />
*2012 Hall A collaboration meeting, P.Zhu ([http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/06062012/beamline%20improvement.pdf beamline])<br />
*2012 JLab User Group Meeting, K. Slifer ([http://hallaweb.jlab.org/experiment/g2p/talks/slifer_g2p_ug12.ppt ppt])<br />
*2012 JLab Graduate Student Seminar, K. Slifer ([http://hallaweb.jlab.org/experiment/g2p/talks/Slifer_g2p_jlab.ppt.pdf pdf])<br />
*2011 Al Gavalya's [http://userweb.jlab.org/~slifer/g2p/figs/g2p_Hall.pdf overview of Hall A]<br />
*2011 NSTAR, K. Slifer ([http://conferences.jlab.org/nstar2011/Thursday%20NSTAR%20Plenary/Slifer_nstar11.ppt.pdf pdf])<br />
*2011 Hall A Workshop, K. Slifer ([http://hallaweb.jlab.org/collab/meeting/2011-summer/talks/day1/Slifer_g2p_hallAcollab_060911.ppt ppt])<br />
*2010 Hall A Collaboration Meeting, K. Allada ([https://userweb.jlab.org/~kalyan/g2p/meetings/HallACollab_Dec2010_Kalyan.pdf])<br />
*2010 One Slide Summary ([http://hallaweb.jlab.org/experiment/g2p/talks/2010_g2p_oneslide.ppt ppt])<br />
*2009 E08-027/E08-007 Presentation to R. McKeown ([http://hallaweb.jlab.org/experiment/g2p/talks/g2p_gep_combined.pdf pdf])<br />
<br />
==g2p Theses==<br />
*[http://hallaweb.jlab.org/experiment/E97-110/thesis.html E97110 List]<br />
<br />
<br />
==Relevent Theses==<br />
*[http://hallaweb.jlab.org/experiment/E97-110/thesis.html E97110 List]<br />
*[http://www.jlab.org/e94010/#Theses E94010 List]<br />
*[http://twist.phys.virginia.edu/~jdm2z/jdm_thesis.pdf J. Maxwell: SANE]<br />
<br />
==Relevent Publications==<br />
*New Insights into the spin structure of the nucleon. [http://prd.aps.org/abstract/PRD/v87/i5/e054032 Phys.Rev. D87 (2013) 054032]<br />
*Axial anomaly and the δLT puzzle. [http://prd.aps.org/abstract/PRD/v85/i1/e016012 Phys. Rev. D 85, 016012 (2012)]<br />
*M. J. Alguard, et al. Deep Inelastic Scattering of Polarized Electrons by Polarized Protons [http://prl.aps.org/abstract/PRL/v37/i19/p1261_1 PRL]<br />
*M. J. Alguard, et al. Elastic Scattering of Polarized Electrons by Polarized Protons [http://prl.aps.org/abstract/PRL/v37/i19/p1258_1 PRL]<br />
*Donnelly and Raskin, Considerations of Polarization in Inclusive Electron Scattering from Nuclei [http://hallaweb.jlab.org/experiment/g2p/papers/Donnelly.pdf pdf]<br />
*Proceedings of the 4th International Workshop on Polarized Target Materials and Techniques, Universitat Bonn [http://hallaweb.jlab.org/experiment/g2p/papers/GreenBook.pdf portrait] [http://hallaweb.jlab.org/experiment/g2p/papers/GreenBook_landscape.pdf landscape]<br />
*Proceedings from BadHonnef, 1995 [http://galileo.phys.virginia.edu/~dbd/BadHonnef1995.pdf pdf]<br />
<br />
==Links==<br />
*[http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/wiki/halog splitted halog]<br />
*[http://phys.huji.ac.il/~gron/ Ron Group] at Hebrew University of Jerusalem.<br />
*The JLab [http://www.jlab.org/exp_prog/experiment_schedule/ schedule] webpage <br />
*[http://clasweb.jlab.org/spin_rotation/ Spin Rotator] website<br />
<br />
==Mailing List==<br />
There are two mailing lists relevant to g2p:<br />
*g2p@jlab.org : General announcements<br />
*g2p_ana@jlab.org : Weekly analysis<br />
You can subscribe to both at http://mailman.jlab.org<br />
<br />
==Help==<br />
*[[Getting_Started_with_the_g2pWiki| HOW-TO]] use the g2pwiki.</div>Melissachttps://hallaweb.jlab.org/wiki/index.php?title=G2p_Analysis_Minutes&diff=26442G2p Analysis Minutes2015-12-16T16:18:10Z<p>Melissac: /* 12/9/2015 */</p>
<hr />
<div>Minutes of the weekly analysis meetings<br />
----<br />
[https://hallaweb.jlab.org/wiki/index.php/G2p_Weekly_Analysis Agenda]<br />
<br />
==12/16/2015==<br />
<br />
<br />
Present: Min, Jixie, Melissa <br><br />
By Phone: Jie, Chao, Ryan, Toby, Ellie <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Toby<br />
**Showed updated dilution results for the 2.2 GeV, 5T longitudinal setting, using the <br>most updated optics matrix. He used a weighted average of the packing fraction <br>values for material 17; there is some drift in the yields for this setting, and therefore <br> some drift in the packing fraction. He showed the effect of applying 4 different<br> acceptance cuts, and found that the structure of the dilution factor was stable. The <br>dilution factor is very dependent on the packing fraction. The method for dilution <br>analysis is complete, but until the yield drifts are completely understood (and final <br>packing fraction values can be extracted), the dilution analysis cannot be finalized. <br>He also started looking at the transverse setting. Before applying any acceptance cuts,<br> he found there was already good agreement between the data and the Bosted prediction.<br> It may not be necessary to apply acceptance cuts at this setting, but it's not clear why <br>there is no acceptance effect. Ryan suggested that the acceptance effect might be <br>minimized since the scattering angle is slightly larger for this configuration.More details <br>can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/diltalk_121615.pdf here].<br />
<br />
'''General Discussion:'''<br />
<br />
*Chao has finished updating the optics databases for all of the LHRS settings. He will <br>update the DB on ifarm so that Toby can replay the data.<br />
<br />
<br />
==12/9/2015==<br />
<br />
<br />
Present: JP, Jixie, Melissa <br><br />
By Phone: Vince, Jie, Chao, Toby, Ellie, Ryan, Min <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Jie<br />
**Compiled a table summarizing the results from his yields study using simulation. In the <br>simulation, the beam position and raster size are taken into account. He also simulated <br>the change in the acceptance from run to run. He found he was able to reproduce the shift <br>in the yields with simulation for about 50% of the runs. There was some question about the <br>sign of the beam position, it's possible there is a difference in the definition of the coordinate <br>systems used by Pengjia and included in the simulation. Jie will double check with Pengjia <br>to make sure the sign is correct. He is also summarizing his results into a technote.<br />
<br />
==12/2/2015==<br />
<br />
<br />
Present: JP, Min, Melissa <br><br />
By Phone: Vince, Jie, Chao, Toby, Ellie, Ryan, Karl, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Toby<br />
**Gave an update on his acceptance and yield study using the updated optics database. He <br>looked at the helium run for one setting in the longitudinal configuration with the smallest p0, <br>since it is way past the delta the dp distribution should be fairly flat. Without applying any <br>acceptance cuts, a sawtooth pattern is seen in the data, while the Bosted model prediction is <br>much flatter. By applying a cut on dp vs phi, he was able to find a region where the dp distribution <br>matches well with the Bosted prediction. Ellie suggested using a minimization procedure, instead <br>of selecting the cut by eye, to improve the results further. Karl cautioned that we don't want to bias<br> our result; we don't necessarily want the distribution to be flat, we just want it to be continuous. JP <br>commented that it is hard to do this without a full acceptance study; Karl suggested varying phi by <br>1-2% to see the effect. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/updatedDB_acc2.pdf here].<br />
<br />
*Min<br />
**Showed very preliminary results for asymmetries for the 1.7 GeV setting. She applied loose acceptance <br>cuts on the focal plane, but will update the results later with cuts on the target plane. She is currently <br>using a constant value for the dilution factor, and hasn't applied radiative corrections. She will work on <br>applying these corrections next. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/asymmetry/12022015_asym.pdf here].<br />
<br />
*Pengjia<br />
**Showed the yield spread for different momentum settings, when different sized raster cuts are applied. JP <br>suggested showing just one momentum setting and showing the effect of the raster cuts for each run. He <br>also suggested starting with a setting that has stable yields, to confirm that the yields are still stable after <br>the raster cuts are applied. More details can be seen in his slide [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/12012015/raster_cut_reliability.pdf here].<br />
<br />
'''General Discussion:'''<br />
<br />
*Jie will give the g2p update at the Hall A Collaboration meeting in January.<br />
<br />
==11/25/2015==<br />
<br />
<br />
Present: JP, Kalyan, Min, Melissa <br><br />
By Phone: Vince, Jie, Toby, Ryan, Karl, Chao <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Showed updated "very preliminary" results for g1/g2. She tried to estimate the uncertainty on the <br>MAID model by comparing it with EG1B data for g1. She looked at the difference between the <br>model prediction and the EG1B results for their lowest values of Q2, and assigned a constant <br>uncertainty of 40% on the MAID model. JP suggested breaking the uncertainty up into different <br>regions, since the data in the delta region matches well with the model prediction but there is a <br>larger discrepancy for higher W. Karl questioned whether the enhancement in the longitudinal <br>asymmetry at large W is real, this will have to be considered carefully for the final analysis. More<br> details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/g1_g2/g1g2_11_25.pdf here].<br />
<br />
*Chao<br />
**Gave an update on the issue with the optics database. Toby showed last week that applying a <br>cut to phi resulted in structure in the dp distribution. Chao scanned the optics matrix to find the <br>element causing this issue, and found that the x^2 and x^3 elements of the phi tensor were causing <br>the over-fitting of the matrix. He showed the dp distribution without these two elements and the <br>unusual structure seen when a cut is placed on phi was gone. JP/Vince commented that it is troubling <br>that the x^2 dependence is causing a problem. They will discuss is more during the optics meeting. <br>More details can be seen in Chao's slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20151125/Chao_WeeklyMeeting_11252015.pdf here].<br />
<br />
==11/18/2015==<br />
<br />
<br />
Present: Min, JP, Melissa <br><br />
By Phone: Vince, Jie, Toby, Ryan, Karl, Ellie, Chao <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Toby<br />
**Gave an update on using the newest optics reconstruction matrix. He showed an example of one<br>run, located way past the delta resonance, so the dp distribution should be fairly flat. He tried <br>applying the phi cuts he has shown previously to remove acceptance and scattering angle effects,<br> but making a cut on phi revealed a strange structure in the dp spectrum. He showed the phi vs. dp <br>reconstruction both at the septum plane (i.e. without target effects) and after being reconstructed <br>back to the target. The strange structure exists in both distributions, so it is probably not a target <br>field effect. He is currently working with Chao to resolve this; Chao is doing a comparison of the <br>old and new databases to determine which element is causing this effect. More details can be seen <br>in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/updatedDB_acc.pdf here].<br />
**He has updated the target polarization uncertainties in the mysql. He will send out an email to the <br>collaboration with more details about this.<br />
<br />
*Pengjia<br />
**Showed the results of a study to check the effect of applying raster cuts on the yield. He showed <br>several examples of groups of runs where the yield was drifting. In some cases, the raster cuts <br>got rid of the drift in the yields, or at least made the drift significantly smaller. For one setting, the <br>raster cut did not resolve the change in yields, so there is likely something else causing the drift. <br>JP suggested doing some sanity check to confirm that the method works, such as starting with <br>a setting that has consistent yields and applying the raster cuts to see the effect. More details <br>can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/11182015/raster_cut_library.pdf here].<br />
<br />
==11/11/2015==<br />
<br />
Present: JP, Melissa <br><br />
By Phone: Vince, Toby, Ryan, Chao, Min, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Showed "very preliminary" results for g1/g2. She is using a dilution factor determined from <br>the Bosted model, and using the average value of the packing fraction for each material. For the <br>radiative corrections, she is using a model prediction for the asymmetry where the polarized piece <br>comes from the MAID model and the unpolarized cross section is the Bosted model. The difference <br>between the model prediction ''without'' radiative effects and the model prediction ''with'' radiative effects <br>is used as an additive correction to the asymmetry. There was some concern over the large effect <br>of the R.C. at high W. Ryan commented that the final R.C will be large, so they will need to be done<br>very carefully. A cross check with EG1 data will be helpful. In order to match the kinematics of the<br>longitudinal and transverse settings, she scaled the asymmetry by the ratio of the unpolarized cross<br>section at the two different kinematic settings. JP commented that this is not valid, and suggested <br>using model input for the asymmetries, instead of trying to match the kinematics between the data<br>taken in the longitudinal and transverse settings. Next she will work on updating systematics for the <br>asymmetries and structure functions. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/g1_g2/g1g2_11_10.pdf here].<br />
<br />
*Chao<br />
**Gave an update on optics analysis. Comparisons of the data with simulation revealed that there <br>were offsets in the reconstructed kinematics. This correction could be fixed using a finely-tuned<br>fitting procedure. The longitudinal setting has already been fixed, today he showed the results <br>for the 1.7 GeV, transverse setting. He showed the results of doing the calibration; most of the <br>holes near the center have a difference of less than 0.5 MeV between data and simulation. He is <br>currently working on finishing the other transverse settings. More details can be found in his <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20151111/Chao_WeeklyMeeting_11112015.pdf here].<br />
<br />
==11/4/2015==<br />
<br />
Present: Min, Jixie, Melissa <br><br />
By Phone: Chao, Vince, Toby, Ryan, Alex, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Ryan<br />
**Gave an overview of g2p elastic tail and angle reconstruction. The elastic tail is highly sensitive<br>to the scattering angle, so his goal is to develop a method to include these variations in the elastic <br>tail subtraction. He started by looking at the simplest case, helium dilution runs. Using his method, <br>he looked at the elastic tail across a series of different momentum settings, andfound that the tail <br>was not continuous, which he assumed was due to variations in the scattering angle. He did a pseudo-<br>simulation using the Bosted model and varying the scattering angle to confirm the "jump" seen in the <br>elastic tail. However, when he looked at the normalized yields for this same data, he did not see the <br>same discontinuity. This suggests there might be a problem with the scattering angle reconstruction. <br>Chao mentioned that the reconstruction code has been updated (at least for the longitudinal setting) <br>the last replay; he will provide this code to Toby so he can do another replay. Details of the method <br>and cuts used can be seen in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_11415.pdf here].<br />
<br />
*Jie<br />
**Gave an update on his simulation study to understand the beam dependence on the yields. He used the <br>beam position and raster size as input to g2psim, and included radiative and acceptance effects. In <br>general, he found there is a much larger dependence on the beam position using a rastered beam <br>compared to a point beam. He summarized his results for various different momentum settings and found <br>that, in some cases, his results matched what we saw in the data, but not in all cases. Vince suggested <br>testing how much the beam position would need to be changed (for a given momentum setting) to match <br>the simulation with the data. The details of his study can be found in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/yields_update_2015_11_04.pdf here], he is also compiling <br>a technote on this analysis.<br />
<br />
==10/28/2015==<br />
<br />
Present: JP, Min, Kalyan, Melissa <br><br />
By Phone: Alexandre, Vince, Jie, Ryan, Toby, Ellie, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Gave an overview of contributions to the systematic uncertainty for the asymmetry. There are <br>several contributions which are very small (<0.1%) including the charge asymmetry, livetime <br>asymmetry and pion contamination. The target polarization uncertainty was surprisingly small.<br>The values currently listed in the mysql DB for this quantity appear to be incorrect; Toby will<br>update these values. For the contribution from the dilution factor and radiative corrections, she<br> assigned 5% as a placeholder until a better estimate could be made. Karl/Ryan commented <br>that 5% uncertainty on the radiative corrections may be too small, 10-15% would be a better<br>estimate at this point. The tables shown for the longitudinal and transverse settings represent<br>an overestimate of the uncertainty; in the long-term this could be looked at more carefully to<br>decrease the overall systematic uncertainty. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Asym/Asym_10_28.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*There has been a request from the Hall A CC to have an update on g2p at the winter collaboration <br>meeting. Ellie and Jie are both interested, they will check the dates of the meetings to see if they <br>are available.<br />
<br />
==10/14/2015==<br />
<br />
Present: JP, Min, Jixie, Kalyan, Melissa <br><br />
By Phone: Alexandre, Vince, Jie, Todd, Haiyan, Pengjia, Karl, Toby, Ryan, Xiaochao, Nilanga, Chao <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Karl<br />
**Went over the goals of the collaboration meeting:<br />
***Discuss physics topics for students graduating soon<br />
***Identify major remaining physics topics<br />
***Establish a policy for the release of plots<br />
**Suggested a policy for collaboration release of physics results, including specific requirements <br>for moving from "very preliminary" to "preliminary" to "final" results. Details can be seen in his <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/slifer/2015/slifer_g2pcollab_101415.pdf here], and they will be circulated to the g2p mailing list with some small modifications.<br />
<br />
*Pengjia<br />
**Will be defending next Wednesday (Oct. 21st). He showed a "very preliminary" physics <br> asymmetry for the 2.2 GeV 5T setting (both longitudinal and transverse) with a comparison to <br> a radiated model prediction. He used this result to extract a preliminary value for g1 and g2,<br>using the Bosted model as input for the cross section. This result does not include radiative<br>corrections. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/graduate_2015.pdf here].<br />
<br />
*Min<br />
**Showed an overview of status of acceptance study; the overall goal is to match the simulation<br>results to the data, so that the simulation can be used to calculate the acceptance. She<br>described the various attempts to correct the simulation results to match the data. Adjusting the<br> apertures based on optics data works well, but the other two methods (adjusting the apertures <br>based on dilution data and adjusting the acceptance cuts after removing the Mott XS from the <br>data) only work well around the target run. In addition, the simulated yield has a different shape <br>than the data, so the simulation must be adjusted to match this. She will go through this process <br>again once Chao is finished with the optics correction. She is planning to graduate next January, <br>and would like to include a cross section difference for one kinematic setting in her thesis. More <br>details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/collab/10142015_collab_Min.pdf here].<br />
<br />
*Melissa<br />
**Gave an overview of packing fraction analysis. Of the 5 total settings there are 3 that are reasonably <br>stable with some small drifts in yields, and 2 settings that have larger problems. During the 2.2 GeV, <br>2.5T setting the raster size was changed, which could possibly be corrected by applying a cut on<br>the center of the raster. The 1.1 GeV setting has large variations in the elastic yields; some of these <br>runs were taken at low currents (8-20nA), so the beam position information is not reliable. She also <br>showed the results of a pion asymmetry study. Although the pion asymmetry is very large, the <br>residual pion contamination after PID cuts are applied is very small, so the correction is not large. <br>She has scheduled her defense for December 4th, and would like to include a preliminary result <br>for g1,g2 in her thesis. To include a fully corrected result she will need preliminary radiative <br>corrections and dilution results, which she will work with Ryan and Toby to get. More details can <br>be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/talks/MCummings_CollabMeeting_20151013.pdf here].<br />
<br />
*Toby<br />
**Showed a preliminary dilution value that he had shown previously, and described several issues <br>with the result. These issues include that the model assumes a constant scattering angle, and does <br>not include some acceptance effects that are seen in the data. He has been working on correcting <br>these issues by incorporating a scattering angle from data into the model and applying acceptance <br>cuts to the data to remove acceptance effects. He showed the result of applying the acceptance cut <br>across all kinematics for the 5T longitudinal setting; including the acceptance cut gets rid of some of <br>the strange structure seen in the yields, such as the sawtooth pattern seen at high nu. The downside <br>of this method is that the acceptance cut causes a large loss in statistics. He is currently working on <br>trying to re-incorporate some of the lost statistics from the acceptance cut. More details can be seen <br>in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/collaborationupdate.pdf here].<br />
<br />
*Jie<br />
**Gave an update on his study using simulation to understand the drifts in yields. He looked at several <br>momentum settings in the 2.2 GeV, 2.5T setting that had variation in the yields. He varied the beam <br>position along the horizontal and vertical directions using both a point beam and rastered beam. He <br>generated a table summarizing the results using a Monte Carlo method, cross checking with averaged <br>acceptance. His results were similar to his previous test using only the Bosted model; some results <br>agree with what was seen in the data, some have the opposite sign. He will write up his method and <br>results in a technote. He is planning to graduate in summer of 2016. More details can be seen in his <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_10_09_simulation/2015_10_14_collaboration_meeting.pdf here].<br />
<br />
*Chao<br />
**Gave an update on optics analysis. Comparisons of simulation with data revealed that the <br>reconstructed kinematics have some offset. A correction was added to the reconstructed kinematics <br>(vs beam position) and he is currently working on merging this correction into the database with a <br>finely tuned fitting procedure. The problem is that the horizontal beam position shifts the dp <br>reconstruction. He showed the results of applying the new optics matrix which corrects for this shift. <br> He will apply this method to all kinematic settings and study the uncertainty of the optics. Once this <br>is done he will write a NIM paper for g2p optics. He plans to graduate in February/March and would <br>like to include the cross section difference for one or two settings with tuned acceptance and model <br>inputs to obtain a physics result. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20151014/Chao_WeeklyMeeting_10142015.pdf here].<br />
<br />
*Ryan<br />
**Since the last collaboration meeting he has improved the model tuning procedure by using an <br>automated procedure instead of tuning the model by hand. He has tested this using carbon data <br>from the UVa database and will run it for nitrogen data once he has updated saGDH N2 cross <br>sections from Vince. He also updated the systematic error study for inelastic unpolarized radiative <br>corrections by separating the integration/iteration error from the interpolation error. He has the <br>polarized radiative correction code running, and has completed a systematic uncertainty study on <br>the inelastic radiative corrections. He is also working on evaluating physics quantities using models, <br>specifically the hyperfine splitting calculation. He plans to graduate in summer/fall of 2016 and would <br>like to include full radiative corrections on g2p polarized cross sections in his thesis. More details can<br> be seen in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_101315.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*Important to do cross checks of results between students (ex. asymmetries)<br />
*Must be careful to include details of any physics results (whether radiative corrections are included,<br>dilution factor, model input instead of data, etc.)<br />
<br />
==9/30/2015==<br />
<br />
Present: JP, Kalyan, Jixie, Min <br><br />
By Phone: Pengjia, Toby, Ryan, Vince, Jie, Chao, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Toby<br />
**Showed an update on his acceptance/dilution study. He continued with the study of the cuts on the <br>reconstructed &theta; vs &phi; distribution at the target. He scanned several different &theta; vs &phi; cuts to see how <br>the acceptance effects the scattering angle and resulting yields. It turns out the small angle region is <br>influenced by the acceptance a lot but the center region gives a good agreement to the model. He <br>also loosed the center cut to &theta; ~ ± 40 mrad and &phi; ~ ± 10 mrad, the data still agreed with the model. <br>He then recalculated the dilution factor for 2.254 GeV longitudinal setting. More details on his <br>acceptance cuts and method can be found in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/diltalk_093015.pdf here].<br />
<br />
<br />
==9/23/2015==<br />
<br />
Present: JP, Kalyan, Min, Melissa <br><br />
By Phone: Pengjia, Toby, Ryan, Vince, Jie, Chao, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Pengjia<br />
**Showed the structure of his code to create a radiated model of the MAID and Bosted <br>models, based on Ryan's radiative correction work. He showed the breakdown of the <br>different components to the radiated model (internal, external and elastic tail). He used<br> the radiated model to calculate an asymmetry and cross section differences, which he <br> compared with data. Finally, he combined asymmetries calculated from data with the <br>Bosted model cross section to calculate a value for g1 and g2, which he compared <br>with values of g1/g2 determined using the MAID model. More details can be seen in <br>his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/09222015/asym_g12.pdf here].<br />
<br />
*Min<br />
**Gave an update on acceptance studies. Last time, she found that by adjusting the<br>apertures in the simulation she could match the data/simulation results for dp (for one <br>momentum setting). She tested this method for other momentum settings and found <br>that it did not work as well. She also showed a comparison of the yield spectrum for<br>helium runs in the 1.7 GeV setting; the shape of the two distributions are quite <br>different, which might suggest that the model deviates significantly form the data. In<br>the simulated results she saw several "bumps" in the yield, which correspond to the<br>location of resonances. She will update these results when the optics corrections are <br>complete. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/09232015.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*We would like to schedule another collaboration meeting in the near future. The <br>meeting is tentatively scheduled for Wednesday October 14th during our usual meeting <br>time (10am-12pm).<br />
*The purpose of the meeting is to:<br />
**Discuss student thesis topics (particularly any updates from the last <br>collaboration meeting)<br />
**Establish a procedure for presentation/release of collaboration plots/results<br />
*Each student should prepare a few slides (~5 minutes) to show analysis progress<br />
<br />
<br />
==9/16/2015==<br />
<br />
Present: Min, JP, Jixie, Melissa <br><br />
By Phone: Vince, Jie, Chao, Pengjia, Alex, Ryan, Toby, Ellie <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Jie<br />
**Gave an update on his simulation study using MUDIFI. Last time he showed that he uses a<br>least square fit to go from endplane to endplane. For the g2p simulation, it's used to go from<br>(x,y,&theta;,&phi;,dp) in the target plane to (x,y,&theta;,&phi;,dp) in the focal plane. SNAKE produces (x,y,&theta;,&phi;,dp)<br>data in both planes and a polynomial function can be used to determine the relationship<br>between the two planes. First the maximum power for each variable is determined, symmetries<br>are included (if applicable), then the priority of each function must be determined. A Gram-<br>Schmidt transformation is used to do the minimization, and the final step is to decide whether<br>to accept the function f<sub>i</sub>. JP/Vince asked how the priority for each function is chosen, since the<br>choice could introduce some ordering dependence. Since we don't have enough data to<br>constrain, JP suggested introducing some physics. He also suggested getting rid of dp in the<br>focal plane (since it is really just dp in the target plane) so that there is one less dimension to<br>fit. More details can be seen in Jie's slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_09_15_simulation/2015_09_15_Simulation_update.pdf here].<br />
<br />
*Ryan<br />
**Gave an update on evaluating physics quantities using models. His goal was to do a<br>comparison of the hyperfine splitting calculation in C. Carlson's 2006/2008 paper using MAID<br>and Hall B models. Previously he showed a comparison using the Hall B model, where he saw<br>good agreement between his calculation and Carlson's result. For this time he also did a<br>comparison using the MAID model. There is a large difference between the two models for the<br>value of the integrand of &Delta;<sub>2</sub>, over the full range of Q<sup>2</sup>. JP suggested comparing the value of g2<br>between the two models, instead of &Delta;<sub>2</sub>. More details can be seen in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_091615.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*Toby<br />
**Last time he showed a comparison between data and cross sections calculated using the<br>Bosted model (seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/acceptance_scatangle.pdf here]). The model was not continuous for one momentum setting. It <br>turns out the BPM was not recording for that setting, so he re-calculated the XS using<br>values for &theta; and &phi; from surrounding runs and found that the result was now consistent with<br>the neighboring momentum settings. He also played around with the acceptance cuts he<br>showed, and found a region using the "extreme cut" where the sawtooth pattern go away<br>and the yields become flat.<br />
<br />
<br />
==9/9/2015==<br />
<br />
Present: Min, JP, Jixie, Melissa <br><br />
By Phone: Vince, Jie, Chao, Ryan, Toby, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Jie<br />
**Gave an overview of his simulation study using SNAKE and MUDIFI. Using SNAKE, the<br>idea is to trace the particle trajectory in a series of free boxes, then an endplane can be<br>defined within the free boxes to determine the trajectory from endplane to endplane. In<br>g2psim this will be used to trace the trajectory between the sieve plane and the focal<br>plane. There are two important issues to consider, the magnetic field in the free boxes,<br>and the transportation method between the two endplanes. A Runge-Kutta method is <br>used for the transportation, and an adaptive method (which changes with field size and<br>gradient) is used to determine the step size. For the magnetic field, a 3D Tosca field<br>map is used for the septum, and an analytic model is used for the spectrometer magnets. <br> He also described the method for choosing the transportation function to determine the <br>25 matrix terms for each kinematic variable (up to 4th order). JP asked how to determine <br>which order is more important, and cautioned to be careful not to over fit the data. He and<br>Jie will discuss this more offline. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_09_09_simulation_update/2015_09_09_Simulation%20update.pdf here].<br />
<br />
*Chao<br />
**Gave an optics status update. The current problem is that changes in the horizontal beam<br>position changes the dp reconstruction. This was fixed by applying a linear correction in<br>BPM-x and BPM-y to &theta;, &phi; and dp. Applying this correction made the data/simulation <br>agree, but it is still necessary to understand the correction. Using dp scan data with beam<br>position scan data still leaves an offset in &theta; and &phi;. He also tried two other methods to do<br>the calibration. Method 1 uses the central hole to determine a constant offset, uses the<br>horizontal beam position scan data to determine all the matrix elements related to y, and<br>uses dp scan runs to fit the additional matrix elements. Method 2 uses beam position<br>scan data to determine the matrix elements that are not related to x<sub>fp</sub>. Neither of these<br>methods works very well, even when the fitting order of the matrix elements are adjusted.<br>He will continue to check more fitting procedures. More details can be found in his slides <br>[http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150909/Chao_WeeklyMeeting_09092015.pdf here].<br />
<br />
*Pengjia<br />
**Gave an update on comparing asymmetries from data/models for the 2.2 GeV, 5T <br>longitudinal setting. He first radiated the Bosted model XS; he showed the break down of<br>the different radiative corrections including the elastic tail (internal and external) and the<br>radiative effects from inelastic scattering. He showed a comparison with Ryan's results<br>which had good agreement, though there is some deviation when he used different proton<br>form factors (provided by Moshe). In order to compare the asymmetry result with data, he<br>needs to do the radiative corrections for the polarized MAID model, which he will continue<br>to work on. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/09092015/asym_20150909.pdf here].<br />
<br />
<br />
==9/2/2015==<br />
<br />
Present: JP, Min, Kalyan, Melissa <br><br />
By Phone: Vince, Alex, Jie, Chao, Ryan, Toby, Ellie, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Gave an update on determining the correction to asymmetries for pion contamination. <br>Previously, she used the 2.2 GeV, 5T longitudinal setting as an example, for this time <br>she used the transverse configuration, as it has the largest pion contamination. She <br>modified her method for differentiating between electrons and pions; previously she <br>identified pions as events that do not trigger the Cherenkov, this time she used a cut <br>below the single photo electron peak to select pions. JP suggested using stricter cuts <br>for selecting pions when determining the pion asymmetry, to make sure it is a clean <br>sample. Although this setting has a large pion contamination, the number of pion<br> events that remain after lead glass cuts are applied is low, so the overall correction <br>is very small. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Pion/PionAsym_08_31.pdf here].<br />
<br />
*Min<br />
**Gave an update on acceptance tuning. She looked at results from the 1.7 GeV setting <br>and found that the height of the peaks is different between data and simulation for <br>different holes in the sieve slit. Looking at the &theta; vs &phi; distribution, she noticed on the<br>positive &theta; side there were fewer holes in simulation than in data, and on the negative <br> &theta; side there were more holes in simulation compared to data. She tried adjusting the<br>aperture cuts by changing the physical location of the Q1, Q2 and septum planes to <br>uncover events that were previously blocked. After the adjustment, the data/simulation <br>results agreed much better. She showed a similar procedure for a dilution run and was<br>able to see better agreement between data/simulation after the aperture adjustments <br>were made. JP/Vince suggested being cautious when adjusting the aperture cuts, as<br> the apertures should be well defined already. They suggested adjusting things that are<br> less well known first, such as the septum field. More details can be seen in her slides<br>[http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/09022015.pdf here].<br />
<br />
*Ryan<br />
**Working on generating physics quantities using models to eventually compare with data.<br>So far, he has incorporated the MAID2007 and Hall B models. He calculated the <br>hyperfine splitting quantities &Delta;1 and &Delta;2 using the Hall B EG1 model and compared them<br> to the results in C. Carlson's 2006 paper. His results agreed very well, he only saw a<br> small deviation for &Delta;2 in the lowest Q<sup>2</sup> range. To check that nothing strange was going <br> on in the low Q<sup>2</sup> range, he calculated &Delta;2 for various small ranges around zero, to ensure<br>that the integration method is well behaved. The Carlson paper also includes calculations <br>using the Simula model, he would like to do a check of this method as well, but is unsure <br>where to find the Simula model. Since he was able to reproduce the hyperfine splitting <br>result, he is confident in his calculation method; it should be straightforward to calculate <br>other spin structure function integrals. More details on his method can be found in his <br>slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_09215.pdf here].<br />
<br />
*Toby<br />
**Showed an update on his acceptance/scattering angle study. He applied cuts of varying<br>strictness on the reconstructed &theta; vs &phi; distribution at the target. He then calculated the <br>real scattering angle before/after scattering for each cut. Using these scattering angles <br> as inputs for the Bosted model he was able to calculate the XS and compare it to data.<br>He showed the comparison between data/Bosted model for each acceptance cut. He <br>hoped that the more extreme acceptance cuts on the data would flatten the yield <br>distribution, but it actually just enhanced the sawtooth pattern. JP questioned why the <br>Bosted prediction for one momentum bin (the green one) was so much lower than the<br> neighboring ones. Toby said the only input that goes into the model is the scattering angle,<br> so it must be considerably different for this momentum setting. He also commented that<br>the model prediction is scaled to match the data, so the scaling enhances the jump in<br>the model. More details on his acceptance cuts and method can be found in his slides<br>[http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/acceptance_scatangle.pdf here].<br />
<br />
<br />
==8/26/2015==<br />
<br />
Present: Jixie, Alex, Min, Kalyan, JP, Chao, Melissa <br><br />
By Phone: Vince, Jie, Ryan, Toby, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Chao<br />
**Gave an update on optics studies. Previously, he showed a comparison between optics data <br>and simulation where he cut on individual sieve holes. For this week, he included a cut on y <br>and dp that he didn't include previously. In the plot of &theta; vs y, JP pointed out that there were <br>additional tails on some sieve holes, Chao says these tails go away when the &phi; cut is <br>included. He showed a 2D plot of &theta; vs &phi;, along with the 1D projection of these variables. JP<br>commented that the data is more smeared out than the simulation, so it is difficult to compare <br>data with simulation results. It's possible that some of the smearing comes from events that <br>punch through the sieve slit and are not being cut out (the simulation currently assumes these <br>events are stopped by the sieve). Looking at the center hole, the data/simulation agree <br>reasonably well, but the agreement gets worse for holes on the edge of the sieve slit. Chao<br>will continue to look into this. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150826/Chao_WeeklyMeeting_08262015.pdf here].<br />
**He also mentioned that ~1 month ago he reported a problem with the [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150708/Chao_WeeklyMeeting_07082015.pdf BPM simulation].<br>He found it was actually a problem with the simulation itself, which has now been updated <br> to correct the problem.<br />
<br />
<br />
'''General Discussion:'''<br />
*Pengjia has submitted his BPM NIM paper.<br />
<br />
<br />
==8/19/2015==<br />
<br />
Present: Chao, Jie, Min, Jixie, Kalyan, Melissa <br><br />
By Phone: Vince, Ryan, Toby, Karl, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Showed a method for determining the correction to asymmetries for pion contamination. The <br>measured asymmetry can be written in terms of the electron and pion asymmetries, multiplied <br>by the fraction of events of that particle. To differentiate between electrons and pions, a cut is<br>made on events that trigger the Cherenkov detector (electrons) and events that do not trigger<br>the Cherenkov (pions). Kalyan commented that this method of selecting pions may be too blind,<br> and suggested making a 2D cut on E/p vs Cherenkov instead. To determine the fraction of<br>electrons/pions, "good event" cuts are applied (loose acceptance cuts, single track events and<br>pion rejector cuts) and the number of electrons/pions that survive the cuts are counted. Although<br>the pion asymmetry is much larger than the electron asymmetry, the number of residual pions<br>is very small, so the overall correction is small. For this example the 2.2 GeV, 5T longitudinal<br>setting was used, but the correction may be larger for the 5T transverse settings, which she <br>will do next. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Pion/PionAsym_08_19.pdf here].<br />
<br />
*Min <br />
**Gave an update on acceptance studies. She used the 1.7 GeV, 2.5T setting (with 3rd septum <br>configuration) to test the acceptance cuts using the yield ratio of data to simulation. She <br>showed a plot of target &theta; vs &phi; for both data and simulation, and applied a graphical cut to get<br>rid of events on the edges. Looking at the resulting 1D plots shows reasonable agreement<br>between &theta; and &phi;. Vince pointed out that there seems to be some additional structure in the<br>dp distribution, and suggested expanding the &delta; cut out to &pm; 4% to see if there is more <br>hidden structure. Min said she has seen this in other settings as well and will look into it. She<br>also tried adjusting the cuts on &theta;, &phi; and &delta; and looked at how the ratio of yields from data/<br>simulation changed; the ratio starts to drop off as the cuts get wider. Next she will work on<br>calculating the yields using W bins. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/08192015.pdf here].<br />
<br />
<br />
==8/12/2015==<br />
<br />
Present: Jie, Chao, Kalyan, Min, Jixie, Melissa <br><br />
By Phone: Pengjia, Ryan, Toby, Karl, Ellie, Alex <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Chao<br />
**Gave an update on optics studies. Previously, Min has shown comparisons of data/simulation<br> where she looked at different columns of sieve holes. Chao continued this study by cutting on <br>individual sieve holes. Looking at the center sieve hole, the &phi; distribution looks reasonable, but <br>the &theta; distribution has some issues. Specifically, the data is wider on the left side (negative &theta;) <br>than the simulation. He showed results for several sieve holes, including one that was in the <br>row as the center hole, but in the farthest column on the left side of the sieve slit. In this case <br>the &theta; distribution had similar width for both data and simulation, but the height of the simulation<br> distribution was larger. This may suggest that something is wrong with the acceptance in the <br>simulation. The problem with &theta; seems to be systematic; for most of the sieve holes there are <br>more events on the left side of the data than in the simulation. Kalyan asked whether the <br>thickness of the sieve slit was taken into account, Chao says it was included in the simulation <br>and optimizer. Jixie suggested comparing the dp distributions for each sieve hole. More details <br>can be seen in Chao's slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150812/Chao_WeeklyMeeting_08122015.pdf here].<br />
<br />
<br />
==7/29/2015==<br />
<br />
Present: Chao, Min, JP, Melissa <br><br />
By Phone: Alex, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Min<br />
**Gave an update on acceptance studies. Previously, Chao showed a correction for the beam<br>position in g2psim. Min checked this correction by looking at optics runs. On the data she <br>applied a cut on dp (to select elastic events) and on the focal plane (to get rid of junk <br> events). On the simulation, only an aperture cut was applied. She compared the data and<br>simulation results for &theta; and &phi; both before and after drifting from the sieve slit to the target.<br>The effect of the target field on &theta; is not very large, though there is a shift down in angle.<br>However, the shape of the &theta; distribution is different between data and simulation. The<br>effect of the target field on &phi; is significant; it's not clear why this is the case. To try to<br>determine the reason for the discrepancies, she applied a cut along each column of sieve<br>slit holes in &phi; and compared the data and simulation results for &theta;,&phi; and dp. Column 2<br>seems to have the best agreement (for dp), columns 1 and 2 have a shift while columns<br>3-6 have a difference in width. Chao suggested also cutting along each row of sieve slit<br>holes to better study the effect of the drift on &phi;. Min will work on identifying the differences<br>between data and simulation, specifically whether the boundaries are different between<br>the two. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07272015/07292015.pdf here].<br />
<br />
<br />
==7/22/2015==<br />
<br />
Present: JP, Min, Jixie, Melissa <br><br />
By Phone: Alex, Ryan, Toby, Ellie, Karl, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Showed various checks for packing fraction runs that have large discrepancies, including <br>beam position, beam energy, spectrometer central momentum setting, septum current, and<br>the location of anneals. For both the 2.2 and 1.1 GeV settings, there are significant shifts in <br>the x and y beam position (2mm or more). She showed the average and standard deviation <br> of epics readings for the LHRS septum current for each run. For several runs, there are small <br>number of epics readings that drift from the average current. It's not clear if this is the <br>current is actually changing or if it is a readout problem. She will look into the yield vs time<br>to try to determine this. JP suggested making a raster cut on the center of the beam to get<br> rid of any potential scraping. Pengjia says there is a way to cut on raster size, but there will<br> be an additional BPM uncertainty. Melissa will discuss this more offline with Pengjia. More<br>details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_07_22.pdf here].<br />
<br />
*Pengjia<br />
**Gave an update on calculating asymmetries/cross sections using the MAID model. This time, <br>he used the Bosted model to get the unpolarized cross sections for the proton. Using unradiated <br>cross section models, he still saw a factor of 6 difference when compared with data. Ryan also <br>calculated asymmetries using unradiated models, and the results were consistent with Pengjia's, <br>so it seems the radiative effects contribute significantly to the factor of 6 difference. More <br>details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07222015/MAID_update_20150722.pdf here].<br />
<br />
<br />
==7/15/2015==<br />
<br />
Present: JP, Min, Chao, Jixie, Melissa <br><br />
By Phone: Ryan, Toby, Ellie, Karl, Vince, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Chao<br />
**Doing a check of simulation/data results for the 2.2 GeV, longitudinal setting in order <br>to check that the optics calibration matrix will work for all momentum settings (not <br>just elastic). He showed a comparison for several different momentum settings.<br> Vince suggested simulating more events, since the statistics start to drop off for <br>lower momentum settings. In general, the data is broader then the result from<br>simulation. In the &theta; distribution, the "tails" seen in the data are not symmetric. JP<br> suggested carefully selecting cuts to remove any background from the data to <br>ensure a good comparison with simulation. More details can be seen in his <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150715/Chao_WeeklyMeeting_07152015.pdf here].<br />
<br />
*Pengjia<br />
**More discussion on Pengjia's [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07082015/MAID_update_20150708.pdf slides] from last week. Pengjia has seen a factor of <br>six difference between his asymmetry calculated from data compared to the <br>asymmetry determined using the MAID model. Ryan did not see this factor of six <br>in his study, but in addition to using radiated XS models, he is using a combination <br>of the Bosted and MAID models (Pengjia is using just the MAID model). Karl <br>commented that the XS from MAID is not very good for our kinematics. Pengjia <br>also showed an estimated NH3 XS. JP commented that it was surprising that the <br>delta peak wasn't visible. Pengjia will look into this for next time.<br />
<br />
<br />
==7/8/2015==<br />
<br />
Present: JP, Min, Chao, Melissa <br><br />
By Phone: Toby, Vince <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Pengjia<br />
**Working on comparing asymmetries determined from MAID to those calculated from <br>data; last time he showed a factor of 6 difference between the two results. This <br>time, he showed two different methods for calculating the differential XS from the <br>virtual photon XS. The first method calculates the differential XS directly from <br>the virtual photon XS, and the second method calculates the differential XS using <br>F<sub>1</sub>, F<sub>2</sub>, g<sub>1</sub> and g<sub>2</sub>. He also showed two different methods for calculating the <br>asymmetry from the virtual photon XS; one method uses A<sub>1</sub> and A<sub>2</sub>, while the other <br>is calculated from the virtual photon XS. There was a discrepancy between the two <br>methods, but he found that there was actually a mistake in one of the equations. <br>While the results from the two methods agree with each other, they are still a factor <br>of 6 larger than the results from data. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07082015/MAID_update_20150708.pdf here].<br />
<br />
*Toby<br />
**Showed an update of his scattering angle study for model reconstruction. He is <br>using BPM and optics data to determine the scattering angle. He showed an example <br>of the calculated scattering angle; JP questioned whether the range was really from <br>0-16 deg. Toby pointed out that there really aren't many events at the boundaries, <br>the distribution is peaked between 4.5-9 deg. He then uses this scattering angle as<br>input for the Bosted model. At low &nu; the simulation results match reasonably well<br>with the data, but the discrepancy starts to become larger as &nu; increases. He took <br>a closer look at the reconstructed scattering angle for each central momentum, and <br>found that a second peak is visible for smaller values of p0. If this second peak was <br>real, the simulation should recreate the data, so this could suggest a problem with <br>the reconstruction. However, Chao pointed out that, for this energy setting, the optics <br>calibration is not complete (currently using the longitudinal optics matrix), so the <br>reconstructed &theta; and &phi; may not be correct yet. For next time, Toby will test this <br>analysis using the 1.7 GeV setting, which has calibrated optics. More details can <br> be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/scatangle_talk.pdf here].<br />
<br />
*Melissa<br />
**Gave a summary of packing fraction analysis. For some settings, the variation in the <br>yields (and P<sub>f</sub>) is due to a fluctuation in the beam position. This will hopefully be<br>resolved by Jie's beam position/acceptance study. For the 2.2 GeV, 2.5T transverse setting<br> there is also an issue of a shift in &nu; between runs. For the 1.1 GeV, 2.5T transverse <br>setting, the yields vary depending on the beam current used for each run. JP suggested <br>a few things to check as the possible cause for these discrepancies including drift in the <br>BCM calibration, anneals of the target material, drift in field (HRS or septum), etc. She <br>has posted a technote draft [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Technotes/PF_technote_draft.pdf here], feedback would be appreciated. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_07_08.pdf here].<br />
<br />
*Min<br />
**Gave an update on her acceptance study. Last time, she showed that the simulation results <br>are more narrow than the data. For this time, she tried cutting on just the center hole, <br>and found that the dp distribution from data better matched the simulation. JP suggested <br>cutting on each of the different holes individually to determine which hole causes the dp <br>distribution to be wider. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07082015/07062015.pdf here].<br />
<br />
*Chao<br />
**Gave an update on optics analysis, currently checking whether simulation results match <br>with data, starting with optics data. First he checked whether the geometry was correct, <br>some deviation was found in the recent optics meeting. The position of the BPMs is hard-<br>coded into the simulation, and the drifting algorithm is used to drift the electrons <br>backward to the BPMs to simulate the readout of BPM A and B. He compared the &theta; <br>distribution before drifting in the target field using a fixed and non-fixed BPM location. <br>The results using a fixed BPM match well with the data. He is currently working on <br>checking this for all momentum settings, and will follow up with Pengjia about the BPM <br>problem. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150708/Chao_WeeklyMeeting_07082015.pdf here].<br />
<br />
<br />
==7/1/2015==<br />
<br />
Present: Chao, Vince, Jie, JP, Min, Melissa <br><br />
By Phone: Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Min<br />
**Gave an update on acceptance studies. She showed a summary table of each energy <br>setting and septum configuration. There hasn't been any problems in the 2.2 GeV, 5T <br>longitudinal and 1.7 GeV, 2.5T transverse settings, but some settings (2.2 GeV, 2.5T <br> transverse, 1.2 GeV, 2.5T transverse and 2.2 GeV, 5T transverse) have a discrepancy <br>in the focal plane between data and simulation. She compared the data divided by the <br>Mott XS to the simulation results without XS, and found that the simulation results <br>of &theta; and &phi; are narrower then the data. JP commented that, while including the Mott<br>XS might change the shape of the distribution, it shouldn't change the boundary. She <br>work on figuring out the cause for this discrepancy before calculating the acceptance. <br>More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07012015/07012015.pdf here].<br />
<br />
*Pengjia<br />
**Comparing asymmetries determined from the MAID model to those calculated from data.<br>Last time he showed a factor of 6 difference between the two results. He determined the <br>scattering angle and Q<sup>2</sup> by fitting the data and compared them to the quantities calculated <br>from MAID. He also showed the results of calculating the quantities g<sub>1</sub>, g<sub>2</sub>, F<sub>1</sub>, F<sub>2</sub>, A<sub>L</sub>, A<sub>T</sub>,<br> dXS<sub>L</sub>, dXS<sub>T</sub>, XS<sub>tot</sub> andXS<sub>mott</sub> using MAID. He hasn't included radiative corrections in his <br>calculations, but this probably won't account for the factor of 6. More details can be seen <br>in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07012015/MAID_20150701.pdf here].<br />
<br />
<br />
----<br />
<br />
==Jan-June 2015==<br />
[[Minutes_Jan2015_to_June2015]]<br />
----<br />
<br />
==July-Dec 2014==<br />
[[Minutes_July2014_to_Dec2014]]<br />
----<br />
<br />
==Jan-June 2014==<br />
[[Minutes_Jan2014_to_June2014]]<br />
----<br />
<br />
==June-Dec 2013==<br />
[[Minutes_June2013_to_Dec2013]]<br />
----<br />
<br />
==Jan-May 2013==<br />
[[Minutes_Jan2013_to_May2013]]<br />
----<br />
<br />
==April-Dec 2012==<br />
[[Minutes_Apr2012_to_Dec2012]]<br />
----<br />
<br />
==Jan-March 2012==<br />
[[Minutes_Jan2012_to_Mar2012]]<br />
----<br />
==July-Dec 2011==<br />
[[Minutes_July2011_to_Dec_2011]]<br />
----<br />
==Jan-June 2011==<br />
[[Minutes_Jan2011_to_June_2011]]<br />
----</div>Melissachttps://hallaweb.jlab.org/wiki/index.php?title=G2p_Analysis_Minutes&diff=26440G2p Analysis Minutes2015-12-16T14:39:20Z<p>Melissac: /* 12/2/2015 */</p>
<hr />
<div>Minutes of the weekly analysis meetings<br />
----<br />
[https://hallaweb.jlab.org/wiki/index.php/G2p_Weekly_Analysis Agenda]<br />
<br />
==12/9/2015==<br />
<br />
<br />
Present: JP, Jixie, Melissa <br><br />
By Phone: Vince, Jie, Chao, Toby, Ellie, Ryan, Min <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Jie<br />
**Compiled a table summarizing the results from his yields study using simulation. In the <br>simulation, the beam position and raster size are taken into account. He also simulated <br>the change in the acceptance from run to run. He found he was able to reproduce the shift <br>in the yields with simulation for about 50% of the runs. There was some question about the <br>sign of the beam position, it's possible there is a difference in the definition of the coordinate <br>systems used by Pengjia and included in the simulation. Jie will double check with Pengjia <br>to make sure the sign is correct. He is also summarizing his results into a technote.<br />
<br />
<br />
==12/2/2015==<br />
<br />
<br />
Present: JP, Min, Melissa <br><br />
By Phone: Vince, Jie, Chao, Toby, Ellie, Ryan, Karl, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Toby<br />
**Gave an update on his acceptance and yield study using the updated optics database. He <br>looked at the helium run for one setting in the longitudinal configuration with the smallest p0, <br>since it is way past the delta the dp distribution should be fairly flat. Without applying any <br>acceptance cuts, a sawtooth pattern is seen in the data, while the Bosted model prediction is <br>much flatter. By applying a cut on dp vs phi, he was able to find a region where the dp distribution <br>matches well with the Bosted prediction. Ellie suggested using a minimization procedure, instead <br>of selecting the cut by eye, to improve the results further. Karl cautioned that we don't want to bias<br> our result; we don't necessarily want the distribution to be flat, we just want it to be continuous. JP <br>commented that it is hard to do this without a full acceptance study; Karl suggested varying phi by <br>1-2% to see the effect. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/updatedDB_acc2.pdf here].<br />
<br />
*Min<br />
**Showed very preliminary results for asymmetries for the 1.7 GeV setting. She applied loose acceptance <br>cuts on the focal plane, but will update the results later with cuts on the target plane. She is currently <br>using a constant value for the dilution factor, and hasn't applied radiative corrections. She will work on <br>applying these corrections next. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/asymmetry/12022015_asym.pdf here].<br />
<br />
*Pengjia<br />
**Showed the yield spread for different momentum settings, when different sized raster cuts are applied. JP <br>suggested showing just one momentum setting and showing the effect of the raster cuts for each run. He <br>also suggested starting with a setting that has stable yields, to confirm that the yields are still stable after <br>the raster cuts are applied. More details can be seen in his slide [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/12012015/raster_cut_reliability.pdf here].<br />
<br />
'''General Discussion:'''<br />
<br />
*Jie will give the g2p update at the Hall A Collaboration meeting in January.<br />
<br />
==11/25/2015==<br />
<br />
<br />
Present: JP, Kalyan, Min, Melissa <br><br />
By Phone: Vince, Jie, Toby, Ryan, Karl, Chao <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Showed updated "very preliminary" results for g1/g2. She tried to estimate the uncertainty on the <br>MAID model by comparing it with EG1B data for g1. She looked at the difference between the <br>model prediction and the EG1B results for their lowest values of Q2, and assigned a constant <br>uncertainty of 40% on the MAID model. JP suggested breaking the uncertainty up into different <br>regions, since the data in the delta region matches well with the model prediction but there is a <br>larger discrepancy for higher W. Karl questioned whether the enhancement in the longitudinal <br>asymmetry at large W is real, this will have to be considered carefully for the final analysis. More<br> details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/g1_g2/g1g2_11_25.pdf here].<br />
<br />
*Chao<br />
**Gave an update on the issue with the optics database. Toby showed last week that applying a <br>cut to phi resulted in structure in the dp distribution. Chao scanned the optics matrix to find the <br>element causing this issue, and found that the x^2 and x^3 elements of the phi tensor were causing <br>the over-fitting of the matrix. He showed the dp distribution without these two elements and the <br>unusual structure seen when a cut is placed on phi was gone. JP/Vince commented that it is troubling <br>that the x^2 dependence is causing a problem. They will discuss is more during the optics meeting. <br>More details can be seen in Chao's slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20151125/Chao_WeeklyMeeting_11252015.pdf here].<br />
<br />
==11/18/2015==<br />
<br />
<br />
Present: Min, JP, Melissa <br><br />
By Phone: Vince, Jie, Toby, Ryan, Karl, Ellie, Chao <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Toby<br />
**Gave an update on using the newest optics reconstruction matrix. He showed an example of one<br>run, located way past the delta resonance, so the dp distribution should be fairly flat. He tried <br>applying the phi cuts he has shown previously to remove acceptance and scattering angle effects,<br> but making a cut on phi revealed a strange structure in the dp spectrum. He showed the phi vs. dp <br>reconstruction both at the septum plane (i.e. without target effects) and after being reconstructed <br>back to the target. The strange structure exists in both distributions, so it is probably not a target <br>field effect. He is currently working with Chao to resolve this; Chao is doing a comparison of the <br>old and new databases to determine which element is causing this effect. More details can be seen <br>in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/updatedDB_acc.pdf here].<br />
**He has updated the target polarization uncertainties in the mysql. He will send out an email to the <br>collaboration with more details about this.<br />
<br />
*Pengjia<br />
**Showed the results of a study to check the effect of applying raster cuts on the yield. He showed <br>several examples of groups of runs where the yield was drifting. In some cases, the raster cuts <br>got rid of the drift in the yields, or at least made the drift significantly smaller. For one setting, the <br>raster cut did not resolve the change in yields, so there is likely something else causing the drift. <br>JP suggested doing some sanity check to confirm that the method works, such as starting with <br>a setting that has consistent yields and applying the raster cuts to see the effect. More details <br>can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/11182015/raster_cut_library.pdf here].<br />
<br />
==11/11/2015==<br />
<br />
Present: JP, Melissa <br><br />
By Phone: Vince, Toby, Ryan, Chao, Min, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Showed "very preliminary" results for g1/g2. She is using a dilution factor determined from <br>the Bosted model, and using the average value of the packing fraction for each material. For the <br>radiative corrections, she is using a model prediction for the asymmetry where the polarized piece <br>comes from the MAID model and the unpolarized cross section is the Bosted model. The difference <br>between the model prediction ''without'' radiative effects and the model prediction ''with'' radiative effects <br>is used as an additive correction to the asymmetry. There was some concern over the large effect <br>of the R.C. at high W. Ryan commented that the final R.C will be large, so they will need to be done<br>very carefully. A cross check with EG1 data will be helpful. In order to match the kinematics of the<br>longitudinal and transverse settings, she scaled the asymmetry by the ratio of the unpolarized cross<br>section at the two different kinematic settings. JP commented that this is not valid, and suggested <br>using model input for the asymmetries, instead of trying to match the kinematics between the data<br>taken in the longitudinal and transverse settings. Next she will work on updating systematics for the <br>asymmetries and structure functions. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/g1_g2/g1g2_11_10.pdf here].<br />
<br />
*Chao<br />
**Gave an update on optics analysis. Comparisons of the data with simulation revealed that there <br>were offsets in the reconstructed kinematics. This correction could be fixed using a finely-tuned<br>fitting procedure. The longitudinal setting has already been fixed, today he showed the results <br>for the 1.7 GeV, transverse setting. He showed the results of doing the calibration; most of the <br>holes near the center have a difference of less than 0.5 MeV between data and simulation. He is <br>currently working on finishing the other transverse settings. More details can be found in his <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20151111/Chao_WeeklyMeeting_11112015.pdf here].<br />
<br />
==11/4/2015==<br />
<br />
Present: Min, Jixie, Melissa <br><br />
By Phone: Chao, Vince, Toby, Ryan, Alex, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Ryan<br />
**Gave an overview of g2p elastic tail and angle reconstruction. The elastic tail is highly sensitive<br>to the scattering angle, so his goal is to develop a method to include these variations in the elastic <br>tail subtraction. He started by looking at the simplest case, helium dilution runs. Using his method, <br>he looked at the elastic tail across a series of different momentum settings, andfound that the tail <br>was not continuous, which he assumed was due to variations in the scattering angle. He did a pseudo-<br>simulation using the Bosted model and varying the scattering angle to confirm the "jump" seen in the <br>elastic tail. However, when he looked at the normalized yields for this same data, he did not see the <br>same discontinuity. This suggests there might be a problem with the scattering angle reconstruction. <br>Chao mentioned that the reconstruction code has been updated (at least for the longitudinal setting) <br>the last replay; he will provide this code to Toby so he can do another replay. Details of the method <br>and cuts used can be seen in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_11415.pdf here].<br />
<br />
*Jie<br />
**Gave an update on his simulation study to understand the beam dependence on the yields. He used the <br>beam position and raster size as input to g2psim, and included radiative and acceptance effects. In <br>general, he found there is a much larger dependence on the beam position using a rastered beam <br>compared to a point beam. He summarized his results for various different momentum settings and found <br>that, in some cases, his results matched what we saw in the data, but not in all cases. Vince suggested <br>testing how much the beam position would need to be changed (for a given momentum setting) to match <br>the simulation with the data. The details of his study can be found in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/yields_update_2015_11_04.pdf here], he is also compiling <br>a technote on this analysis.<br />
<br />
==10/28/2015==<br />
<br />
Present: JP, Min, Kalyan, Melissa <br><br />
By Phone: Alexandre, Vince, Jie, Ryan, Toby, Ellie, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Gave an overview of contributions to the systematic uncertainty for the asymmetry. There are <br>several contributions which are very small (<0.1%) including the charge asymmetry, livetime <br>asymmetry and pion contamination. The target polarization uncertainty was surprisingly small.<br>The values currently listed in the mysql DB for this quantity appear to be incorrect; Toby will<br>update these values. For the contribution from the dilution factor and radiative corrections, she<br> assigned 5% as a placeholder until a better estimate could be made. Karl/Ryan commented <br>that 5% uncertainty on the radiative corrections may be too small, 10-15% would be a better<br>estimate at this point. The tables shown for the longitudinal and transverse settings represent<br>an overestimate of the uncertainty; in the long-term this could be looked at more carefully to<br>decrease the overall systematic uncertainty. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Asym/Asym_10_28.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*There has been a request from the Hall A CC to have an update on g2p at the winter collaboration <br>meeting. Ellie and Jie are both interested, they will check the dates of the meetings to see if they <br>are available.<br />
<br />
==10/14/2015==<br />
<br />
Present: JP, Min, Jixie, Kalyan, Melissa <br><br />
By Phone: Alexandre, Vince, Jie, Todd, Haiyan, Pengjia, Karl, Toby, Ryan, Xiaochao, Nilanga, Chao <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Karl<br />
**Went over the goals of the collaboration meeting:<br />
***Discuss physics topics for students graduating soon<br />
***Identify major remaining physics topics<br />
***Establish a policy for the release of plots<br />
**Suggested a policy for collaboration release of physics results, including specific requirements <br>for moving from "very preliminary" to "preliminary" to "final" results. Details can be seen in his <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/slifer/2015/slifer_g2pcollab_101415.pdf here], and they will be circulated to the g2p mailing list with some small modifications.<br />
<br />
*Pengjia<br />
**Will be defending next Wednesday (Oct. 21st). He showed a "very preliminary" physics <br> asymmetry for the 2.2 GeV 5T setting (both longitudinal and transverse) with a comparison to <br> a radiated model prediction. He used this result to extract a preliminary value for g1 and g2,<br>using the Bosted model as input for the cross section. This result does not include radiative<br>corrections. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/graduate_2015.pdf here].<br />
<br />
*Min<br />
**Showed an overview of status of acceptance study; the overall goal is to match the simulation<br>results to the data, so that the simulation can be used to calculate the acceptance. She<br>described the various attempts to correct the simulation results to match the data. Adjusting the<br> apertures based on optics data works well, but the other two methods (adjusting the apertures <br>based on dilution data and adjusting the acceptance cuts after removing the Mott XS from the <br>data) only work well around the target run. In addition, the simulated yield has a different shape <br>than the data, so the simulation must be adjusted to match this. She will go through this process <br>again once Chao is finished with the optics correction. She is planning to graduate next January, <br>and would like to include a cross section difference for one kinematic setting in her thesis. More <br>details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/collab/10142015_collab_Min.pdf here].<br />
<br />
*Melissa<br />
**Gave an overview of packing fraction analysis. Of the 5 total settings there are 3 that are reasonably <br>stable with some small drifts in yields, and 2 settings that have larger problems. During the 2.2 GeV, <br>2.5T setting the raster size was changed, which could possibly be corrected by applying a cut on<br>the center of the raster. The 1.1 GeV setting has large variations in the elastic yields; some of these <br>runs were taken at low currents (8-20nA), so the beam position information is not reliable. She also <br>showed the results of a pion asymmetry study. Although the pion asymmetry is very large, the <br>residual pion contamination after PID cuts are applied is very small, so the correction is not large. <br>She has scheduled her defense for December 4th, and would like to include a preliminary result <br>for g1,g2 in her thesis. To include a fully corrected result she will need preliminary radiative <br>corrections and dilution results, which she will work with Ryan and Toby to get. More details can <br>be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/talks/MCummings_CollabMeeting_20151013.pdf here].<br />
<br />
*Toby<br />
**Showed a preliminary dilution value that he had shown previously, and described several issues <br>with the result. These issues include that the model assumes a constant scattering angle, and does <br>not include some acceptance effects that are seen in the data. He has been working on correcting <br>these issues by incorporating a scattering angle from data into the model and applying acceptance <br>cuts to the data to remove acceptance effects. He showed the result of applying the acceptance cut <br>across all kinematics for the 5T longitudinal setting; including the acceptance cut gets rid of some of <br>the strange structure seen in the yields, such as the sawtooth pattern seen at high nu. The downside <br>of this method is that the acceptance cut causes a large loss in statistics. He is currently working on <br>trying to re-incorporate some of the lost statistics from the acceptance cut. More details can be seen <br>in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/collaborationupdate.pdf here].<br />
<br />
*Jie<br />
**Gave an update on his study using simulation to understand the drifts in yields. He looked at several <br>momentum settings in the 2.2 GeV, 2.5T setting that had variation in the yields. He varied the beam <br>position along the horizontal and vertical directions using both a point beam and rastered beam. He <br>generated a table summarizing the results using a Monte Carlo method, cross checking with averaged <br>acceptance. His results were similar to his previous test using only the Bosted model; some results <br>agree with what was seen in the data, some have the opposite sign. He will write up his method and <br>results in a technote. He is planning to graduate in summer of 2016. More details can be seen in his <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_10_09_simulation/2015_10_14_collaboration_meeting.pdf here].<br />
<br />
*Chao<br />
**Gave an update on optics analysis. Comparisons of simulation with data revealed that the <br>reconstructed kinematics have some offset. A correction was added to the reconstructed kinematics <br>(vs beam position) and he is currently working on merging this correction into the database with a <br>finely tuned fitting procedure. The problem is that the horizontal beam position shifts the dp <br>reconstruction. He showed the results of applying the new optics matrix which corrects for this shift. <br> He will apply this method to all kinematic settings and study the uncertainty of the optics. Once this <br>is done he will write a NIM paper for g2p optics. He plans to graduate in February/March and would <br>like to include the cross section difference for one or two settings with tuned acceptance and model <br>inputs to obtain a physics result. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20151014/Chao_WeeklyMeeting_10142015.pdf here].<br />
<br />
*Ryan<br />
**Since the last collaboration meeting he has improved the model tuning procedure by using an <br>automated procedure instead of tuning the model by hand. He has tested this using carbon data <br>from the UVa database and will run it for nitrogen data once he has updated saGDH N2 cross <br>sections from Vince. He also updated the systematic error study for inelastic unpolarized radiative <br>corrections by separating the integration/iteration error from the interpolation error. He has the <br>polarized radiative correction code running, and has completed a systematic uncertainty study on <br>the inelastic radiative corrections. He is also working on evaluating physics quantities using models, <br>specifically the hyperfine splitting calculation. He plans to graduate in summer/fall of 2016 and would <br>like to include full radiative corrections on g2p polarized cross sections in his thesis. More details can<br> be seen in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_101315.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*Important to do cross checks of results between students (ex. asymmetries)<br />
*Must be careful to include details of any physics results (whether radiative corrections are included,<br>dilution factor, model input instead of data, etc.)<br />
<br />
==9/30/2015==<br />
<br />
Present: JP, Kalyan, Jixie, Min <br><br />
By Phone: Pengjia, Toby, Ryan, Vince, Jie, Chao, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Toby<br />
**Showed an update on his acceptance/dilution study. He continued with the study of the cuts on the <br>reconstructed &theta; vs &phi; distribution at the target. He scanned several different &theta; vs &phi; cuts to see how <br>the acceptance effects the scattering angle and resulting yields. It turns out the small angle region is <br>influenced by the acceptance a lot but the center region gives a good agreement to the model. He <br>also loosed the center cut to &theta; ~ ± 40 mrad and &phi; ~ ± 10 mrad, the data still agreed with the model. <br>He then recalculated the dilution factor for 2.254 GeV longitudinal setting. More details on his <br>acceptance cuts and method can be found in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/diltalk_093015.pdf here].<br />
<br />
<br />
==9/23/2015==<br />
<br />
Present: JP, Kalyan, Min, Melissa <br><br />
By Phone: Pengjia, Toby, Ryan, Vince, Jie, Chao, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Pengjia<br />
**Showed the structure of his code to create a radiated model of the MAID and Bosted <br>models, based on Ryan's radiative correction work. He showed the breakdown of the <br>different components to the radiated model (internal, external and elastic tail). He used<br> the radiated model to calculate an asymmetry and cross section differences, which he <br> compared with data. Finally, he combined asymmetries calculated from data with the <br>Bosted model cross section to calculate a value for g1 and g2, which he compared <br>with values of g1/g2 determined using the MAID model. More details can be seen in <br>his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/09222015/asym_g12.pdf here].<br />
<br />
*Min<br />
**Gave an update on acceptance studies. Last time, she found that by adjusting the<br>apertures in the simulation she could match the data/simulation results for dp (for one <br>momentum setting). She tested this method for other momentum settings and found <br>that it did not work as well. She also showed a comparison of the yield spectrum for<br>helium runs in the 1.7 GeV setting; the shape of the two distributions are quite <br>different, which might suggest that the model deviates significantly form the data. In<br>the simulated results she saw several "bumps" in the yield, which correspond to the<br>location of resonances. She will update these results when the optics corrections are <br>complete. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/09232015.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*We would like to schedule another collaboration meeting in the near future. The <br>meeting is tentatively scheduled for Wednesday October 14th during our usual meeting <br>time (10am-12pm).<br />
*The purpose of the meeting is to:<br />
**Discuss student thesis topics (particularly any updates from the last <br>collaboration meeting)<br />
**Establish a procedure for presentation/release of collaboration plots/results<br />
*Each student should prepare a few slides (~5 minutes) to show analysis progress<br />
<br />
<br />
==9/16/2015==<br />
<br />
Present: Min, JP, Jixie, Melissa <br><br />
By Phone: Vince, Jie, Chao, Pengjia, Alex, Ryan, Toby, Ellie <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Jie<br />
**Gave an update on his simulation study using MUDIFI. Last time he showed that he uses a<br>least square fit to go from endplane to endplane. For the g2p simulation, it's used to go from<br>(x,y,&theta;,&phi;,dp) in the target plane to (x,y,&theta;,&phi;,dp) in the focal plane. SNAKE produces (x,y,&theta;,&phi;,dp)<br>data in both planes and a polynomial function can be used to determine the relationship<br>between the two planes. First the maximum power for each variable is determined, symmetries<br>are included (if applicable), then the priority of each function must be determined. A Gram-<br>Schmidt transformation is used to do the minimization, and the final step is to decide whether<br>to accept the function f<sub>i</sub>. JP/Vince asked how the priority for each function is chosen, since the<br>choice could introduce some ordering dependence. Since we don't have enough data to<br>constrain, JP suggested introducing some physics. He also suggested getting rid of dp in the<br>focal plane (since it is really just dp in the target plane) so that there is one less dimension to<br>fit. More details can be seen in Jie's slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_09_15_simulation/2015_09_15_Simulation_update.pdf here].<br />
<br />
*Ryan<br />
**Gave an update on evaluating physics quantities using models. His goal was to do a<br>comparison of the hyperfine splitting calculation in C. Carlson's 2006/2008 paper using MAID<br>and Hall B models. Previously he showed a comparison using the Hall B model, where he saw<br>good agreement between his calculation and Carlson's result. For this time he also did a<br>comparison using the MAID model. There is a large difference between the two models for the<br>value of the integrand of &Delta;<sub>2</sub>, over the full range of Q<sup>2</sup>. JP suggested comparing the value of g2<br>between the two models, instead of &Delta;<sub>2</sub>. More details can be seen in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_091615.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*Toby<br />
**Last time he showed a comparison between data and cross sections calculated using the<br>Bosted model (seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/acceptance_scatangle.pdf here]). The model was not continuous for one momentum setting. It <br>turns out the BPM was not recording for that setting, so he re-calculated the XS using<br>values for &theta; and &phi; from surrounding runs and found that the result was now consistent with<br>the neighboring momentum settings. He also played around with the acceptance cuts he<br>showed, and found a region using the "extreme cut" where the sawtooth pattern go away<br>and the yields become flat.<br />
<br />
<br />
==9/9/2015==<br />
<br />
Present: Min, JP, Jixie, Melissa <br><br />
By Phone: Vince, Jie, Chao, Ryan, Toby, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Jie<br />
**Gave an overview of his simulation study using SNAKE and MUDIFI. Using SNAKE, the<br>idea is to trace the particle trajectory in a series of free boxes, then an endplane can be<br>defined within the free boxes to determine the trajectory from endplane to endplane. In<br>g2psim this will be used to trace the trajectory between the sieve plane and the focal<br>plane. There are two important issues to consider, the magnetic field in the free boxes,<br>and the transportation method between the two endplanes. A Runge-Kutta method is <br>used for the transportation, and an adaptive method (which changes with field size and<br>gradient) is used to determine the step size. For the magnetic field, a 3D Tosca field<br>map is used for the septum, and an analytic model is used for the spectrometer magnets. <br> He also described the method for choosing the transportation function to determine the <br>25 matrix terms for each kinematic variable (up to 4th order). JP asked how to determine <br>which order is more important, and cautioned to be careful not to over fit the data. He and<br>Jie will discuss this more offline. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_09_09_simulation_update/2015_09_09_Simulation%20update.pdf here].<br />
<br />
*Chao<br />
**Gave an optics status update. The current problem is that changes in the horizontal beam<br>position changes the dp reconstruction. This was fixed by applying a linear correction in<br>BPM-x and BPM-y to &theta;, &phi; and dp. Applying this correction made the data/simulation <br>agree, but it is still necessary to understand the correction. Using dp scan data with beam<br>position scan data still leaves an offset in &theta; and &phi;. He also tried two other methods to do<br>the calibration. Method 1 uses the central hole to determine a constant offset, uses the<br>horizontal beam position scan data to determine all the matrix elements related to y, and<br>uses dp scan runs to fit the additional matrix elements. Method 2 uses beam position<br>scan data to determine the matrix elements that are not related to x<sub>fp</sub>. Neither of these<br>methods works very well, even when the fitting order of the matrix elements are adjusted.<br>He will continue to check more fitting procedures. More details can be found in his slides <br>[http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150909/Chao_WeeklyMeeting_09092015.pdf here].<br />
<br />
*Pengjia<br />
**Gave an update on comparing asymmetries from data/models for the 2.2 GeV, 5T <br>longitudinal setting. He first radiated the Bosted model XS; he showed the break down of<br>the different radiative corrections including the elastic tail (internal and external) and the<br>radiative effects from inelastic scattering. He showed a comparison with Ryan's results<br>which had good agreement, though there is some deviation when he used different proton<br>form factors (provided by Moshe). In order to compare the asymmetry result with data, he<br>needs to do the radiative corrections for the polarized MAID model, which he will continue<br>to work on. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/09092015/asym_20150909.pdf here].<br />
<br />
<br />
==9/2/2015==<br />
<br />
Present: JP, Min, Kalyan, Melissa <br><br />
By Phone: Vince, Alex, Jie, Chao, Ryan, Toby, Ellie, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Gave an update on determining the correction to asymmetries for pion contamination. <br>Previously, she used the 2.2 GeV, 5T longitudinal setting as an example, for this time <br>she used the transverse configuration, as it has the largest pion contamination. She <br>modified her method for differentiating between electrons and pions; previously she <br>identified pions as events that do not trigger the Cherenkov, this time she used a cut <br>below the single photo electron peak to select pions. JP suggested using stricter cuts <br>for selecting pions when determining the pion asymmetry, to make sure it is a clean <br>sample. Although this setting has a large pion contamination, the number of pion<br> events that remain after lead glass cuts are applied is low, so the overall correction <br>is very small. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Pion/PionAsym_08_31.pdf here].<br />
<br />
*Min<br />
**Gave an update on acceptance tuning. She looked at results from the 1.7 GeV setting <br>and found that the height of the peaks is different between data and simulation for <br>different holes in the sieve slit. Looking at the &theta; vs &phi; distribution, she noticed on the<br>positive &theta; side there were fewer holes in simulation than in data, and on the negative <br> &theta; side there were more holes in simulation compared to data. She tried adjusting the<br>aperture cuts by changing the physical location of the Q1, Q2 and septum planes to <br>uncover events that were previously blocked. After the adjustment, the data/simulation <br>results agreed much better. She showed a similar procedure for a dilution run and was<br>able to see better agreement between data/simulation after the aperture adjustments <br>were made. JP/Vince suggested being cautious when adjusting the aperture cuts, as<br> the apertures should be well defined already. They suggested adjusting things that are<br> less well known first, such as the septum field. More details can be seen in her slides<br>[http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/09022015.pdf here].<br />
<br />
*Ryan<br />
**Working on generating physics quantities using models to eventually compare with data.<br>So far, he has incorporated the MAID2007 and Hall B models. He calculated the <br>hyperfine splitting quantities &Delta;1 and &Delta;2 using the Hall B EG1 model and compared them<br> to the results in C. Carlson's 2006 paper. His results agreed very well, he only saw a<br> small deviation for &Delta;2 in the lowest Q<sup>2</sup> range. To check that nothing strange was going <br> on in the low Q<sup>2</sup> range, he calculated &Delta;2 for various small ranges around zero, to ensure<br>that the integration method is well behaved. The Carlson paper also includes calculations <br>using the Simula model, he would like to do a check of this method as well, but is unsure <br>where to find the Simula model. Since he was able to reproduce the hyperfine splitting <br>result, he is confident in his calculation method; it should be straightforward to calculate <br>other spin structure function integrals. More details on his method can be found in his <br>slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_09215.pdf here].<br />
<br />
*Toby<br />
**Showed an update on his acceptance/scattering angle study. He applied cuts of varying<br>strictness on the reconstructed &theta; vs &phi; distribution at the target. He then calculated the <br>real scattering angle before/after scattering for each cut. Using these scattering angles <br> as inputs for the Bosted model he was able to calculate the XS and compare it to data.<br>He showed the comparison between data/Bosted model for each acceptance cut. He <br>hoped that the more extreme acceptance cuts on the data would flatten the yield <br>distribution, but it actually just enhanced the sawtooth pattern. JP questioned why the <br>Bosted prediction for one momentum bin (the green one) was so much lower than the<br> neighboring ones. Toby said the only input that goes into the model is the scattering angle,<br> so it must be considerably different for this momentum setting. He also commented that<br>the model prediction is scaled to match the data, so the scaling enhances the jump in<br>the model. More details on his acceptance cuts and method can be found in his slides<br>[http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/acceptance_scatangle.pdf here].<br />
<br />
<br />
==8/26/2015==<br />
<br />
Present: Jixie, Alex, Min, Kalyan, JP, Chao, Melissa <br><br />
By Phone: Vince, Jie, Ryan, Toby, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Chao<br />
**Gave an update on optics studies. Previously, he showed a comparison between optics data <br>and simulation where he cut on individual sieve holes. For this week, he included a cut on y <br>and dp that he didn't include previously. In the plot of &theta; vs y, JP pointed out that there were <br>additional tails on some sieve holes, Chao says these tails go away when the &phi; cut is <br>included. He showed a 2D plot of &theta; vs &phi;, along with the 1D projection of these variables. JP<br>commented that the data is more smeared out than the simulation, so it is difficult to compare <br>data with simulation results. It's possible that some of the smearing comes from events that <br>punch through the sieve slit and are not being cut out (the simulation currently assumes these <br>events are stopped by the sieve). Looking at the center hole, the data/simulation agree <br>reasonably well, but the agreement gets worse for holes on the edge of the sieve slit. Chao<br>will continue to look into this. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150826/Chao_WeeklyMeeting_08262015.pdf here].<br />
**He also mentioned that ~1 month ago he reported a problem with the [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150708/Chao_WeeklyMeeting_07082015.pdf BPM simulation].<br>He found it was actually a problem with the simulation itself, which has now been updated <br> to correct the problem.<br />
<br />
<br />
'''General Discussion:'''<br />
*Pengjia has submitted his BPM NIM paper.<br />
<br />
<br />
==8/19/2015==<br />
<br />
Present: Chao, Jie, Min, Jixie, Kalyan, Melissa <br><br />
By Phone: Vince, Ryan, Toby, Karl, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Showed a method for determining the correction to asymmetries for pion contamination. The <br>measured asymmetry can be written in terms of the electron and pion asymmetries, multiplied <br>by the fraction of events of that particle. To differentiate between electrons and pions, a cut is<br>made on events that trigger the Cherenkov detector (electrons) and events that do not trigger<br>the Cherenkov (pions). Kalyan commented that this method of selecting pions may be too blind,<br> and suggested making a 2D cut on E/p vs Cherenkov instead. To determine the fraction of<br>electrons/pions, "good event" cuts are applied (loose acceptance cuts, single track events and<br>pion rejector cuts) and the number of electrons/pions that survive the cuts are counted. Although<br>the pion asymmetry is much larger than the electron asymmetry, the number of residual pions<br>is very small, so the overall correction is small. For this example the 2.2 GeV, 5T longitudinal<br>setting was used, but the correction may be larger for the 5T transverse settings, which she <br>will do next. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Pion/PionAsym_08_19.pdf here].<br />
<br />
*Min <br />
**Gave an update on acceptance studies. She used the 1.7 GeV, 2.5T setting (with 3rd septum <br>configuration) to test the acceptance cuts using the yield ratio of data to simulation. She <br>showed a plot of target &theta; vs &phi; for both data and simulation, and applied a graphical cut to get<br>rid of events on the edges. Looking at the resulting 1D plots shows reasonable agreement<br>between &theta; and &phi;. Vince pointed out that there seems to be some additional structure in the<br>dp distribution, and suggested expanding the &delta; cut out to &pm; 4% to see if there is more <br>hidden structure. Min said she has seen this in other settings as well and will look into it. She<br>also tried adjusting the cuts on &theta;, &phi; and &delta; and looked at how the ratio of yields from data/<br>simulation changed; the ratio starts to drop off as the cuts get wider. Next she will work on<br>calculating the yields using W bins. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/08192015.pdf here].<br />
<br />
<br />
==8/12/2015==<br />
<br />
Present: Jie, Chao, Kalyan, Min, Jixie, Melissa <br><br />
By Phone: Pengjia, Ryan, Toby, Karl, Ellie, Alex <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Chao<br />
**Gave an update on optics studies. Previously, Min has shown comparisons of data/simulation<br> where she looked at different columns of sieve holes. Chao continued this study by cutting on <br>individual sieve holes. Looking at the center sieve hole, the &phi; distribution looks reasonable, but <br>the &theta; distribution has some issues. Specifically, the data is wider on the left side (negative &theta;) <br>than the simulation. He showed results for several sieve holes, including one that was in the <br>row as the center hole, but in the farthest column on the left side of the sieve slit. In this case <br>the &theta; distribution had similar width for both data and simulation, but the height of the simulation<br> distribution was larger. This may suggest that something is wrong with the acceptance in the <br>simulation. The problem with &theta; seems to be systematic; for most of the sieve holes there are <br>more events on the left side of the data than in the simulation. Kalyan asked whether the <br>thickness of the sieve slit was taken into account, Chao says it was included in the simulation <br>and optimizer. Jixie suggested comparing the dp distributions for each sieve hole. More details <br>can be seen in Chao's slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150812/Chao_WeeklyMeeting_08122015.pdf here].<br />
<br />
<br />
==7/29/2015==<br />
<br />
Present: Chao, Min, JP, Melissa <br><br />
By Phone: Alex, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Min<br />
**Gave an update on acceptance studies. Previously, Chao showed a correction for the beam<br>position in g2psim. Min checked this correction by looking at optics runs. On the data she <br>applied a cut on dp (to select elastic events) and on the focal plane (to get rid of junk <br> events). On the simulation, only an aperture cut was applied. She compared the data and<br>simulation results for &theta; and &phi; both before and after drifting from the sieve slit to the target.<br>The effect of the target field on &theta; is not very large, though there is a shift down in angle.<br>However, the shape of the &theta; distribution is different between data and simulation. The<br>effect of the target field on &phi; is significant; it's not clear why this is the case. To try to<br>determine the reason for the discrepancies, she applied a cut along each column of sieve<br>slit holes in &phi; and compared the data and simulation results for &theta;,&phi; and dp. Column 2<br>seems to have the best agreement (for dp), columns 1 and 2 have a shift while columns<br>3-6 have a difference in width. Chao suggested also cutting along each row of sieve slit<br>holes to better study the effect of the drift on &phi;. Min will work on identifying the differences<br>between data and simulation, specifically whether the boundaries are different between<br>the two. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07272015/07292015.pdf here].<br />
<br />
<br />
==7/22/2015==<br />
<br />
Present: JP, Min, Jixie, Melissa <br><br />
By Phone: Alex, Ryan, Toby, Ellie, Karl, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Showed various checks for packing fraction runs that have large discrepancies, including <br>beam position, beam energy, spectrometer central momentum setting, septum current, and<br>the location of anneals. For both the 2.2 and 1.1 GeV settings, there are significant shifts in <br>the x and y beam position (2mm or more). She showed the average and standard deviation <br> of epics readings for the LHRS septum current for each run. For several runs, there are small <br>number of epics readings that drift from the average current. It's not clear if this is the <br>current is actually changing or if it is a readout problem. She will look into the yield vs time<br>to try to determine this. JP suggested making a raster cut on the center of the beam to get<br> rid of any potential scraping. Pengjia says there is a way to cut on raster size, but there will<br> be an additional BPM uncertainty. Melissa will discuss this more offline with Pengjia. More<br>details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_07_22.pdf here].<br />
<br />
*Pengjia<br />
**Gave an update on calculating asymmetries/cross sections using the MAID model. This time, <br>he used the Bosted model to get the unpolarized cross sections for the proton. Using unradiated <br>cross section models, he still saw a factor of 6 difference when compared with data. Ryan also <br>calculated asymmetries using unradiated models, and the results were consistent with Pengjia's, <br>so it seems the radiative effects contribute significantly to the factor of 6 difference. More <br>details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07222015/MAID_update_20150722.pdf here].<br />
<br />
<br />
==7/15/2015==<br />
<br />
Present: JP, Min, Chao, Jixie, Melissa <br><br />
By Phone: Ryan, Toby, Ellie, Karl, Vince, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Chao<br />
**Doing a check of simulation/data results for the 2.2 GeV, longitudinal setting in order <br>to check that the optics calibration matrix will work for all momentum settings (not <br>just elastic). He showed a comparison for several different momentum settings.<br> Vince suggested simulating more events, since the statistics start to drop off for <br>lower momentum settings. In general, the data is broader then the result from<br>simulation. In the &theta; distribution, the "tails" seen in the data are not symmetric. JP<br> suggested carefully selecting cuts to remove any background from the data to <br>ensure a good comparison with simulation. More details can be seen in his <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150715/Chao_WeeklyMeeting_07152015.pdf here].<br />
<br />
*Pengjia<br />
**More discussion on Pengjia's [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07082015/MAID_update_20150708.pdf slides] from last week. Pengjia has seen a factor of <br>six difference between his asymmetry calculated from data compared to the <br>asymmetry determined using the MAID model. Ryan did not see this factor of six <br>in his study, but in addition to using radiated XS models, he is using a combination <br>of the Bosted and MAID models (Pengjia is using just the MAID model). Karl <br>commented that the XS from MAID is not very good for our kinematics. Pengjia <br>also showed an estimated NH3 XS. JP commented that it was surprising that the <br>delta peak wasn't visible. Pengjia will look into this for next time.<br />
<br />
<br />
==7/8/2015==<br />
<br />
Present: JP, Min, Chao, Melissa <br><br />
By Phone: Toby, Vince <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Pengjia<br />
**Working on comparing asymmetries determined from MAID to those calculated from <br>data; last time he showed a factor of 6 difference between the two results. This <br>time, he showed two different methods for calculating the differential XS from the <br>virtual photon XS. The first method calculates the differential XS directly from <br>the virtual photon XS, and the second method calculates the differential XS using <br>F<sub>1</sub>, F<sub>2</sub>, g<sub>1</sub> and g<sub>2</sub>. He also showed two different methods for calculating the <br>asymmetry from the virtual photon XS; one method uses A<sub>1</sub> and A<sub>2</sub>, while the other <br>is calculated from the virtual photon XS. There was a discrepancy between the two <br>methods, but he found that there was actually a mistake in one of the equations. <br>While the results from the two methods agree with each other, they are still a factor <br>of 6 larger than the results from data. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07082015/MAID_update_20150708.pdf here].<br />
<br />
*Toby<br />
**Showed an update of his scattering angle study for model reconstruction. He is <br>using BPM and optics data to determine the scattering angle. He showed an example <br>of the calculated scattering angle; JP questioned whether the range was really from <br>0-16 deg. Toby pointed out that there really aren't many events at the boundaries, <br>the distribution is peaked between 4.5-9 deg. He then uses this scattering angle as<br>input for the Bosted model. At low &nu; the simulation results match reasonably well<br>with the data, but the discrepancy starts to become larger as &nu; increases. He took <br>a closer look at the reconstructed scattering angle for each central momentum, and <br>found that a second peak is visible for smaller values of p0. If this second peak was <br>real, the simulation should recreate the data, so this could suggest a problem with <br>the reconstruction. However, Chao pointed out that, for this energy setting, the optics <br>calibration is not complete (currently using the longitudinal optics matrix), so the <br>reconstructed &theta; and &phi; may not be correct yet. For next time, Toby will test this <br>analysis using the 1.7 GeV setting, which has calibrated optics. More details can <br> be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/scatangle_talk.pdf here].<br />
<br />
*Melissa<br />
**Gave a summary of packing fraction analysis. For some settings, the variation in the <br>yields (and P<sub>f</sub>) is due to a fluctuation in the beam position. This will hopefully be<br>resolved by Jie's beam position/acceptance study. For the 2.2 GeV, 2.5T transverse setting<br> there is also an issue of a shift in &nu; between runs. For the 1.1 GeV, 2.5T transverse <br>setting, the yields vary depending on the beam current used for each run. JP suggested <br>a few things to check as the possible cause for these discrepancies including drift in the <br>BCM calibration, anneals of the target material, drift in field (HRS or septum), etc. She <br>has posted a technote draft [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Technotes/PF_technote_draft.pdf here], feedback would be appreciated. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_07_08.pdf here].<br />
<br />
*Min<br />
**Gave an update on her acceptance study. Last time, she showed that the simulation results <br>are more narrow than the data. For this time, she tried cutting on just the center hole, <br>and found that the dp distribution from data better matched the simulation. JP suggested <br>cutting on each of the different holes individually to determine which hole causes the dp <br>distribution to be wider. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07082015/07062015.pdf here].<br />
<br />
*Chao<br />
**Gave an update on optics analysis, currently checking whether simulation results match <br>with data, starting with optics data. First he checked whether the geometry was correct, <br>some deviation was found in the recent optics meeting. The position of the BPMs is hard-<br>coded into the simulation, and the drifting algorithm is used to drift the electrons <br>backward to the BPMs to simulate the readout of BPM A and B. He compared the &theta; <br>distribution before drifting in the target field using a fixed and non-fixed BPM location. <br>The results using a fixed BPM match well with the data. He is currently working on <br>checking this for all momentum settings, and will follow up with Pengjia about the BPM <br>problem. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150708/Chao_WeeklyMeeting_07082015.pdf here].<br />
<br />
<br />
==7/1/2015==<br />
<br />
Present: Chao, Vince, Jie, JP, Min, Melissa <br><br />
By Phone: Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Min<br />
**Gave an update on acceptance studies. She showed a summary table of each energy <br>setting and septum configuration. There hasn't been any problems in the 2.2 GeV, 5T <br>longitudinal and 1.7 GeV, 2.5T transverse settings, but some settings (2.2 GeV, 2.5T <br> transverse, 1.2 GeV, 2.5T transverse and 2.2 GeV, 5T transverse) have a discrepancy <br>in the focal plane between data and simulation. She compared the data divided by the <br>Mott XS to the simulation results without XS, and found that the simulation results <br>of &theta; and &phi; are narrower then the data. JP commented that, while including the Mott<br>XS might change the shape of the distribution, it shouldn't change the boundary. She <br>work on figuring out the cause for this discrepancy before calculating the acceptance. <br>More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07012015/07012015.pdf here].<br />
<br />
*Pengjia<br />
**Comparing asymmetries determined from the MAID model to those calculated from data.<br>Last time he showed a factor of 6 difference between the two results. He determined the <br>scattering angle and Q<sup>2</sup> by fitting the data and compared them to the quantities calculated <br>from MAID. He also showed the results of calculating the quantities g<sub>1</sub>, g<sub>2</sub>, F<sub>1</sub>, F<sub>2</sub>, A<sub>L</sub>, A<sub>T</sub>,<br> dXS<sub>L</sub>, dXS<sub>T</sub>, XS<sub>tot</sub> andXS<sub>mott</sub> using MAID. He hasn't included radiative corrections in his <br>calculations, but this probably won't account for the factor of 6. More details can be seen <br>in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07012015/MAID_20150701.pdf here].<br />
<br />
<br />
----<br />
<br />
==Jan-June 2015==<br />
[[Minutes_Jan2015_to_June2015]]<br />
----<br />
<br />
==July-Dec 2014==<br />
[[Minutes_July2014_to_Dec2014]]<br />
----<br />
<br />
==Jan-June 2014==<br />
[[Minutes_Jan2014_to_June2014]]<br />
----<br />
<br />
==June-Dec 2013==<br />
[[Minutes_June2013_to_Dec2013]]<br />
----<br />
<br />
==Jan-May 2013==<br />
[[Minutes_Jan2013_to_May2013]]<br />
----<br />
<br />
==April-Dec 2012==<br />
[[Minutes_Apr2012_to_Dec2012]]<br />
----<br />
<br />
==Jan-March 2012==<br />
[[Minutes_Jan2012_to_Mar2012]]<br />
----<br />
==July-Dec 2011==<br />
[[Minutes_July2011_to_Dec_2011]]<br />
----<br />
==Jan-June 2011==<br />
[[Minutes_Jan2011_to_June_2011]]<br />
----</div>Melissachttps://hallaweb.jlab.org/wiki/index.php?title=G2p_Analysis_Minutes&diff=26414G2p Analysis Minutes2015-12-09T14:47:20Z<p>Melissac: /* 11/25/2015 */</p>
<hr />
<div>Minutes of the weekly analysis meetings<br />
----<br />
[https://hallaweb.jlab.org/wiki/index.php/G2p_Weekly_Analysis Agenda]<br />
<br />
==12/2/2015==<br />
<br />
<br />
Present: JP, Min, Melissa <br><br />
By Phone: Vince, Jie, Chao, Toby, Ellie, Ryan, Karl, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Toby<br />
**Gave an update on his acceptance and yield study using the updated optics database. He <br>looked at the helium run for one setting in the longitudinal configuration with the smallest p0, <br>since it is way past the delta the dp distribution should be fairly flat. Without applying any <br>acceptance cuts, a sawtooth pattern is seen in the data, while the Bosted model prediction is <br>much flatter. By applying a cut on dp vs phi, he was able to find a region where the dp distribution <br>matches well with the Bosted prediction. Ellie suggested using a minimization procedure, instead <br>of selecting the cut by eye, to improve the results further. Karl cautioned that we don't want to bias<br> our result; we don't necessarily want the distribution to be flat, we just want it to be continuous. JP <br>commented that it is hard to do this without a full acceptance study; Karl suggested varying phi by <br>1-2% to see the effect. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/updatedDB_acc2.pdf here].<br />
<br />
*Min<br />
**Showed very preliminary results for asymmetries for the 1.7 GeV setting. She applied loose acceptance <br>cuts on the focal plane, but will update the results later with cuts on the target plane. She is currently <br>using a constant value for the dilution factor, and hasn't applied radiative corrections. She will work on <br>applying these corrections next. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/asymmetry/12022015_asym.pdf here].<br />
<br />
*Pengjia<br />
**Showed the yield spread for different momentum settings, when different sized raster cuts are applied. JP <br>suggested showing just one momentum setting and showing the effect of the raster cuts for each run. He <br>also suggested starting with a setting that has stable yields, to confirm that the yields are still stable after <br>the raster cuts are applied. More details can be seen in his slide [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/12012015/raster_cut_reliability.pdf here].<br />
<br />
'''General Discussion:'''<br />
<br />
*Jie will give the g2p update at the Hall A Collaboration meeting in January.<br />
<br />
<br />
==11/25/2015==<br />
<br />
<br />
Present: JP, Kalyan, Min, Melissa <br><br />
By Phone: Vince, Jie, Toby, Ryan, Karl, Chao <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Showed updated "very preliminary" results for g1/g2. She tried to estimate the uncertainty on the <br>MAID model by comparing it with EG1B data for g1. She looked at the difference between the <br>model prediction and the EG1B results for their lowest values of Q2, and assigned a constant <br>uncertainty of 40% on the MAID model. JP suggested breaking the uncertainty up into different <br>regions, since the data in the delta region matches well with the model prediction but there is a <br>larger discrepancy for higher W. Karl questioned whether the enhancement in the longitudinal <br>asymmetry at large W is real, this will have to be considered carefully for the final analysis. More<br> details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/g1_g2/g1g2_11_25.pdf here].<br />
<br />
*Chao<br />
**Gave an update on the issue with the optics database. Toby showed last week that applying a <br>cut to phi resulted in structure in the dp distribution. Chao scanned the optics matrix to find the <br>element causing this issue, and found that the x^2 and x^3 elements of the phi tensor were causing <br>the over-fitting of the matrix. He showed the dp distribution without these two elements and the <br>unusual structure seen when a cut is placed on phi was gone. JP/Vince commented that it is troubling <br>that the x^2 dependence is causing a problem. They will discuss is more during the optics meeting. <br>More details can be seen in Chao's slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20151125/Chao_WeeklyMeeting_11252015.pdf here].<br />
<br />
==11/18/2015==<br />
<br />
<br />
Present: Min, JP, Melissa <br><br />
By Phone: Vince, Jie, Toby, Ryan, Karl, Ellie, Chao <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Toby<br />
**Gave an update on using the newest optics reconstruction matrix. He showed an example of one<br>run, located way past the delta resonance, so the dp distribution should be fairly flat. He tried <br>applying the phi cuts he has shown previously to remove acceptance and scattering angle effects,<br> but making a cut on phi revealed a strange structure in the dp spectrum. He showed the phi vs. dp <br>reconstruction both at the septum plane (i.e. without target effects) and after being reconstructed <br>back to the target. The strange structure exists in both distributions, so it is probably not a target <br>field effect. He is currently working with Chao to resolve this; Chao is doing a comparison of the <br>old and new databases to determine which element is causing this effect. More details can be seen <br>in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/updatedDB_acc.pdf here].<br />
**He has updated the target polarization uncertainties in the mysql. He will send out an email to the <br>collaboration with more details about this.<br />
<br />
*Pengjia<br />
**Showed the results of a study to check the effect of applying raster cuts on the yield. He showed <br>several examples of groups of runs where the yield was drifting. In some cases, the raster cuts <br>got rid of the drift in the yields, or at least made the drift significantly smaller. For one setting, the <br>raster cut did not resolve the change in yields, so there is likely something else causing the drift. <br>JP suggested doing some sanity check to confirm that the method works, such as starting with <br>a setting that has consistent yields and applying the raster cuts to see the effect. More details <br>can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/11182015/raster_cut_library.pdf here].<br />
<br />
==11/11/2015==<br />
<br />
Present: JP, Melissa <br><br />
By Phone: Vince, Toby, Ryan, Chao, Min, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Showed "very preliminary" results for g1/g2. She is using a dilution factor determined from <br>the Bosted model, and using the average value of the packing fraction for each material. For the <br>radiative corrections, she is using a model prediction for the asymmetry where the polarized piece <br>comes from the MAID model and the unpolarized cross section is the Bosted model. The difference <br>between the model prediction ''without'' radiative effects and the model prediction ''with'' radiative effects <br>is used as an additive correction to the asymmetry. There was some concern over the large effect <br>of the R.C. at high W. Ryan commented that the final R.C will be large, so they will need to be done<br>very carefully. A cross check with EG1 data will be helpful. In order to match the kinematics of the<br>longitudinal and transverse settings, she scaled the asymmetry by the ratio of the unpolarized cross<br>section at the two different kinematic settings. JP commented that this is not valid, and suggested <br>using model input for the asymmetries, instead of trying to match the kinematics between the data<br>taken in the longitudinal and transverse settings. Next she will work on updating systematics for the <br>asymmetries and structure functions. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/g1_g2/g1g2_11_10.pdf here].<br />
<br />
*Chao<br />
**Gave an update on optics analysis. Comparisons of the data with simulation revealed that there <br>were offsets in the reconstructed kinematics. This correction could be fixed using a finely-tuned<br>fitting procedure. The longitudinal setting has already been fixed, today he showed the results <br>for the 1.7 GeV, transverse setting. He showed the results of doing the calibration; most of the <br>holes near the center have a difference of less than 0.5 MeV between data and simulation. He is <br>currently working on finishing the other transverse settings. More details can be found in his <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20151111/Chao_WeeklyMeeting_11112015.pdf here].<br />
<br />
==11/4/2015==<br />
<br />
Present: Min, Jixie, Melissa <br><br />
By Phone: Chao, Vince, Toby, Ryan, Alex, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Ryan<br />
**Gave an overview of g2p elastic tail and angle reconstruction. The elastic tail is highly sensitive<br>to the scattering angle, so his goal is to develop a method to include these variations in the elastic <br>tail subtraction. He started by looking at the simplest case, helium dilution runs. Using his method, <br>he looked at the elastic tail across a series of different momentum settings, andfound that the tail <br>was not continuous, which he assumed was due to variations in the scattering angle. He did a pseudo-<br>simulation using the Bosted model and varying the scattering angle to confirm the "jump" seen in the <br>elastic tail. However, when he looked at the normalized yields for this same data, he did not see the <br>same discontinuity. This suggests there might be a problem with the scattering angle reconstruction. <br>Chao mentioned that the reconstruction code has been updated (at least for the longitudinal setting) <br>the last replay; he will provide this code to Toby so he can do another replay. Details of the method <br>and cuts used can be seen in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_11415.pdf here].<br />
<br />
*Jie<br />
**Gave an update on his simulation study to understand the beam dependence on the yields. He used the <br>beam position and raster size as input to g2psim, and included radiative and acceptance effects. In <br>general, he found there is a much larger dependence on the beam position using a rastered beam <br>compared to a point beam. He summarized his results for various different momentum settings and found <br>that, in some cases, his results matched what we saw in the data, but not in all cases. Vince suggested <br>testing how much the beam position would need to be changed (for a given momentum setting) to match <br>the simulation with the data. The details of his study can be found in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/yields_update_2015_11_04.pdf here], he is also compiling <br>a technote on this analysis.<br />
<br />
==10/28/2015==<br />
<br />
Present: JP, Min, Kalyan, Melissa <br><br />
By Phone: Alexandre, Vince, Jie, Ryan, Toby, Ellie, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Gave an overview of contributions to the systematic uncertainty for the asymmetry. There are <br>several contributions which are very small (<0.1%) including the charge asymmetry, livetime <br>asymmetry and pion contamination. The target polarization uncertainty was surprisingly small.<br>The values currently listed in the mysql DB for this quantity appear to be incorrect; Toby will<br>update these values. For the contribution from the dilution factor and radiative corrections, she<br> assigned 5% as a placeholder until a better estimate could be made. Karl/Ryan commented <br>that 5% uncertainty on the radiative corrections may be too small, 10-15% would be a better<br>estimate at this point. The tables shown for the longitudinal and transverse settings represent<br>an overestimate of the uncertainty; in the long-term this could be looked at more carefully to<br>decrease the overall systematic uncertainty. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Asym/Asym_10_28.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*There has been a request from the Hall A CC to have an update on g2p at the winter collaboration <br>meeting. Ellie and Jie are both interested, they will check the dates of the meetings to see if they <br>are available.<br />
<br />
==10/14/2015==<br />
<br />
Present: JP, Min, Jixie, Kalyan, Melissa <br><br />
By Phone: Alexandre, Vince, Jie, Todd, Haiyan, Pengjia, Karl, Toby, Ryan, Xiaochao, Nilanga, Chao <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Karl<br />
**Went over the goals of the collaboration meeting:<br />
***Discuss physics topics for students graduating soon<br />
***Identify major remaining physics topics<br />
***Establish a policy for the release of plots<br />
**Suggested a policy for collaboration release of physics results, including specific requirements <br>for moving from "very preliminary" to "preliminary" to "final" results. Details can be seen in his <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/slifer/2015/slifer_g2pcollab_101415.pdf here], and they will be circulated to the g2p mailing list with some small modifications.<br />
<br />
*Pengjia<br />
**Will be defending next Wednesday (Oct. 21st). He showed a "very preliminary" physics <br> asymmetry for the 2.2 GeV 5T setting (both longitudinal and transverse) with a comparison to <br> a radiated model prediction. He used this result to extract a preliminary value for g1 and g2,<br>using the Bosted model as input for the cross section. This result does not include radiative<br>corrections. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/graduate_2015.pdf here].<br />
<br />
*Min<br />
**Showed an overview of status of acceptance study; the overall goal is to match the simulation<br>results to the data, so that the simulation can be used to calculate the acceptance. She<br>described the various attempts to correct the simulation results to match the data. Adjusting the<br> apertures based on optics data works well, but the other two methods (adjusting the apertures <br>based on dilution data and adjusting the acceptance cuts after removing the Mott XS from the <br>data) only work well around the target run. In addition, the simulated yield has a different shape <br>than the data, so the simulation must be adjusted to match this. She will go through this process <br>again once Chao is finished with the optics correction. She is planning to graduate next January, <br>and would like to include a cross section difference for one kinematic setting in her thesis. More <br>details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/collab/10142015_collab_Min.pdf here].<br />
<br />
*Melissa<br />
**Gave an overview of packing fraction analysis. Of the 5 total settings there are 3 that are reasonably <br>stable with some small drifts in yields, and 2 settings that have larger problems. During the 2.2 GeV, <br>2.5T setting the raster size was changed, which could possibly be corrected by applying a cut on<br>the center of the raster. The 1.1 GeV setting has large variations in the elastic yields; some of these <br>runs were taken at low currents (8-20nA), so the beam position information is not reliable. She also <br>showed the results of a pion asymmetry study. Although the pion asymmetry is very large, the <br>residual pion contamination after PID cuts are applied is very small, so the correction is not large. <br>She has scheduled her defense for December 4th, and would like to include a preliminary result <br>for g1,g2 in her thesis. To include a fully corrected result she will need preliminary radiative <br>corrections and dilution results, which she will work with Ryan and Toby to get. More details can <br>be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/talks/MCummings_CollabMeeting_20151013.pdf here].<br />
<br />
*Toby<br />
**Showed a preliminary dilution value that he had shown previously, and described several issues <br>with the result. These issues include that the model assumes a constant scattering angle, and does <br>not include some acceptance effects that are seen in the data. He has been working on correcting <br>these issues by incorporating a scattering angle from data into the model and applying acceptance <br>cuts to the data to remove acceptance effects. He showed the result of applying the acceptance cut <br>across all kinematics for the 5T longitudinal setting; including the acceptance cut gets rid of some of <br>the strange structure seen in the yields, such as the sawtooth pattern seen at high nu. The downside <br>of this method is that the acceptance cut causes a large loss in statistics. He is currently working on <br>trying to re-incorporate some of the lost statistics from the acceptance cut. More details can be seen <br>in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/collaborationupdate.pdf here].<br />
<br />
*Jie<br />
**Gave an update on his study using simulation to understand the drifts in yields. He looked at several <br>momentum settings in the 2.2 GeV, 2.5T setting that had variation in the yields. He varied the beam <br>position along the horizontal and vertical directions using both a point beam and rastered beam. He <br>generated a table summarizing the results using a Monte Carlo method, cross checking with averaged <br>acceptance. His results were similar to his previous test using only the Bosted model; some results <br>agree with what was seen in the data, some have the opposite sign. He will write up his method and <br>results in a technote. He is planning to graduate in summer of 2016. More details can be seen in his <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_10_09_simulation/2015_10_14_collaboration_meeting.pdf here].<br />
<br />
*Chao<br />
**Gave an update on optics analysis. Comparisons of simulation with data revealed that the <br>reconstructed kinematics have some offset. A correction was added to the reconstructed kinematics <br>(vs beam position) and he is currently working on merging this correction into the database with a <br>finely tuned fitting procedure. The problem is that the horizontal beam position shifts the dp <br>reconstruction. He showed the results of applying the new optics matrix which corrects for this shift. <br> He will apply this method to all kinematic settings and study the uncertainty of the optics. Once this <br>is done he will write a NIM paper for g2p optics. He plans to graduate in February/March and would <br>like to include the cross section difference for one or two settings with tuned acceptance and model <br>inputs to obtain a physics result. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20151014/Chao_WeeklyMeeting_10142015.pdf here].<br />
<br />
*Ryan<br />
**Since the last collaboration meeting he has improved the model tuning procedure by using an <br>automated procedure instead of tuning the model by hand. He has tested this using carbon data <br>from the UVa database and will run it for nitrogen data once he has updated saGDH N2 cross <br>sections from Vince. He also updated the systematic error study for inelastic unpolarized radiative <br>corrections by separating the integration/iteration error from the interpolation error. He has the <br>polarized radiative correction code running, and has completed a systematic uncertainty study on <br>the inelastic radiative corrections. He is also working on evaluating physics quantities using models, <br>specifically the hyperfine splitting calculation. He plans to graduate in summer/fall of 2016 and would <br>like to include full radiative corrections on g2p polarized cross sections in his thesis. More details can<br> be seen in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_101315.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*Important to do cross checks of results between students (ex. asymmetries)<br />
*Must be careful to include details of any physics results (whether radiative corrections are included,<br>dilution factor, model input instead of data, etc.)<br />
<br />
==9/30/2015==<br />
<br />
Present: JP, Kalyan, Jixie, Min <br><br />
By Phone: Pengjia, Toby, Ryan, Vince, Jie, Chao, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Toby<br />
**Showed an update on his acceptance/dilution study. He continued with the study of the cuts on the <br>reconstructed &theta; vs &phi; distribution at the target. He scanned several different &theta; vs &phi; cuts to see how <br>the acceptance effects the scattering angle and resulting yields. It turns out the small angle region is <br>influenced by the acceptance a lot but the center region gives a good agreement to the model. He <br>also loosed the center cut to &theta; ~ ± 40 mrad and &phi; ~ ± 10 mrad, the data still agreed with the model. <br>He then recalculated the dilution factor for 2.254 GeV longitudinal setting. More details on his <br>acceptance cuts and method can be found in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/diltalk_093015.pdf here].<br />
<br />
<br />
==9/23/2015==<br />
<br />
Present: JP, Kalyan, Min, Melissa <br><br />
By Phone: Pengjia, Toby, Ryan, Vince, Jie, Chao, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Pengjia<br />
**Showed the structure of his code to create a radiated model of the MAID and Bosted <br>models, based on Ryan's radiative correction work. He showed the breakdown of the <br>different components to the radiated model (internal, external and elastic tail). He used<br> the radiated model to calculate an asymmetry and cross section differences, which he <br> compared with data. Finally, he combined asymmetries calculated from data with the <br>Bosted model cross section to calculate a value for g1 and g2, which he compared <br>with values of g1/g2 determined using the MAID model. More details can be seen in <br>his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/09222015/asym_g12.pdf here].<br />
<br />
*Min<br />
**Gave an update on acceptance studies. Last time, she found that by adjusting the<br>apertures in the simulation she could match the data/simulation results for dp (for one <br>momentum setting). She tested this method for other momentum settings and found <br>that it did not work as well. She also showed a comparison of the yield spectrum for<br>helium runs in the 1.7 GeV setting; the shape of the two distributions are quite <br>different, which might suggest that the model deviates significantly form the data. In<br>the simulated results she saw several "bumps" in the yield, which correspond to the<br>location of resonances. She will update these results when the optics corrections are <br>complete. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/09232015.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*We would like to schedule another collaboration meeting in the near future. The <br>meeting is tentatively scheduled for Wednesday October 14th during our usual meeting <br>time (10am-12pm).<br />
*The purpose of the meeting is to:<br />
**Discuss student thesis topics (particularly any updates from the last <br>collaboration meeting)<br />
**Establish a procedure for presentation/release of collaboration plots/results<br />
*Each student should prepare a few slides (~5 minutes) to show analysis progress<br />
<br />
<br />
==9/16/2015==<br />
<br />
Present: Min, JP, Jixie, Melissa <br><br />
By Phone: Vince, Jie, Chao, Pengjia, Alex, Ryan, Toby, Ellie <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Jie<br />
**Gave an update on his simulation study using MUDIFI. Last time he showed that he uses a<br>least square fit to go from endplane to endplane. For the g2p simulation, it's used to go from<br>(x,y,&theta;,&phi;,dp) in the target plane to (x,y,&theta;,&phi;,dp) in the focal plane. SNAKE produces (x,y,&theta;,&phi;,dp)<br>data in both planes and a polynomial function can be used to determine the relationship<br>between the two planes. First the maximum power for each variable is determined, symmetries<br>are included (if applicable), then the priority of each function must be determined. A Gram-<br>Schmidt transformation is used to do the minimization, and the final step is to decide whether<br>to accept the function f<sub>i</sub>. JP/Vince asked how the priority for each function is chosen, since the<br>choice could introduce some ordering dependence. Since we don't have enough data to<br>constrain, JP suggested introducing some physics. He also suggested getting rid of dp in the<br>focal plane (since it is really just dp in the target plane) so that there is one less dimension to<br>fit. More details can be seen in Jie's slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_09_15_simulation/2015_09_15_Simulation_update.pdf here].<br />
<br />
*Ryan<br />
**Gave an update on evaluating physics quantities using models. His goal was to do a<br>comparison of the hyperfine splitting calculation in C. Carlson's 2006/2008 paper using MAID<br>and Hall B models. Previously he showed a comparison using the Hall B model, where he saw<br>good agreement between his calculation and Carlson's result. For this time he also did a<br>comparison using the MAID model. There is a large difference between the two models for the<br>value of the integrand of &Delta;<sub>2</sub>, over the full range of Q<sup>2</sup>. JP suggested comparing the value of g2<br>between the two models, instead of &Delta;<sub>2</sub>. More details can be seen in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_091615.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*Toby<br />
**Last time he showed a comparison between data and cross sections calculated using the<br>Bosted model (seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/acceptance_scatangle.pdf here]). The model was not continuous for one momentum setting. It <br>turns out the BPM was not recording for that setting, so he re-calculated the XS using<br>values for &theta; and &phi; from surrounding runs and found that the result was now consistent with<br>the neighboring momentum settings. He also played around with the acceptance cuts he<br>showed, and found a region using the "extreme cut" where the sawtooth pattern go away<br>and the yields become flat.<br />
<br />
<br />
==9/9/2015==<br />
<br />
Present: Min, JP, Jixie, Melissa <br><br />
By Phone: Vince, Jie, Chao, Ryan, Toby, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Jie<br />
**Gave an overview of his simulation study using SNAKE and MUDIFI. Using SNAKE, the<br>idea is to trace the particle trajectory in a series of free boxes, then an endplane can be<br>defined within the free boxes to determine the trajectory from endplane to endplane. In<br>g2psim this will be used to trace the trajectory between the sieve plane and the focal<br>plane. There are two important issues to consider, the magnetic field in the free boxes,<br>and the transportation method between the two endplanes. A Runge-Kutta method is <br>used for the transportation, and an adaptive method (which changes with field size and<br>gradient) is used to determine the step size. For the magnetic field, a 3D Tosca field<br>map is used for the septum, and an analytic model is used for the spectrometer magnets. <br> He also described the method for choosing the transportation function to determine the <br>25 matrix terms for each kinematic variable (up to 4th order). JP asked how to determine <br>which order is more important, and cautioned to be careful not to over fit the data. He and<br>Jie will discuss this more offline. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_09_09_simulation_update/2015_09_09_Simulation%20update.pdf here].<br />
<br />
*Chao<br />
**Gave an optics status update. The current problem is that changes in the horizontal beam<br>position changes the dp reconstruction. This was fixed by applying a linear correction in<br>BPM-x and BPM-y to &theta;, &phi; and dp. Applying this correction made the data/simulation <br>agree, but it is still necessary to understand the correction. Using dp scan data with beam<br>position scan data still leaves an offset in &theta; and &phi;. He also tried two other methods to do<br>the calibration. Method 1 uses the central hole to determine a constant offset, uses the<br>horizontal beam position scan data to determine all the matrix elements related to y, and<br>uses dp scan runs to fit the additional matrix elements. Method 2 uses beam position<br>scan data to determine the matrix elements that are not related to x<sub>fp</sub>. Neither of these<br>methods works very well, even when the fitting order of the matrix elements are adjusted.<br>He will continue to check more fitting procedures. More details can be found in his slides <br>[http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150909/Chao_WeeklyMeeting_09092015.pdf here].<br />
<br />
*Pengjia<br />
**Gave an update on comparing asymmetries from data/models for the 2.2 GeV, 5T <br>longitudinal setting. He first radiated the Bosted model XS; he showed the break down of<br>the different radiative corrections including the elastic tail (internal and external) and the<br>radiative effects from inelastic scattering. He showed a comparison with Ryan's results<br>which had good agreement, though there is some deviation when he used different proton<br>form factors (provided by Moshe). In order to compare the asymmetry result with data, he<br>needs to do the radiative corrections for the polarized MAID model, which he will continue<br>to work on. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/09092015/asym_20150909.pdf here].<br />
<br />
<br />
==9/2/2015==<br />
<br />
Present: JP, Min, Kalyan, Melissa <br><br />
By Phone: Vince, Alex, Jie, Chao, Ryan, Toby, Ellie, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Gave an update on determining the correction to asymmetries for pion contamination. <br>Previously, she used the 2.2 GeV, 5T longitudinal setting as an example, for this time <br>she used the transverse configuration, as it has the largest pion contamination. She <br>modified her method for differentiating between electrons and pions; previously she <br>identified pions as events that do not trigger the Cherenkov, this time she used a cut <br>below the single photo electron peak to select pions. JP suggested using stricter cuts <br>for selecting pions when determining the pion asymmetry, to make sure it is a clean <br>sample. Although this setting has a large pion contamination, the number of pion<br> events that remain after lead glass cuts are applied is low, so the overall correction <br>is very small. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Pion/PionAsym_08_31.pdf here].<br />
<br />
*Min<br />
**Gave an update on acceptance tuning. She looked at results from the 1.7 GeV setting <br>and found that the height of the peaks is different between data and simulation for <br>different holes in the sieve slit. Looking at the &theta; vs &phi; distribution, she noticed on the<br>positive &theta; side there were fewer holes in simulation than in data, and on the negative <br> &theta; side there were more holes in simulation compared to data. She tried adjusting the<br>aperture cuts by changing the physical location of the Q1, Q2 and septum planes to <br>uncover events that were previously blocked. After the adjustment, the data/simulation <br>results agreed much better. She showed a similar procedure for a dilution run and was<br>able to see better agreement between data/simulation after the aperture adjustments <br>were made. JP/Vince suggested being cautious when adjusting the aperture cuts, as<br> the apertures should be well defined already. They suggested adjusting things that are<br> less well known first, such as the septum field. More details can be seen in her slides<br>[http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/09022015.pdf here].<br />
<br />
*Ryan<br />
**Working on generating physics quantities using models to eventually compare with data.<br>So far, he has incorporated the MAID2007 and Hall B models. He calculated the <br>hyperfine splitting quantities &Delta;1 and &Delta;2 using the Hall B EG1 model and compared them<br> to the results in C. Carlson's 2006 paper. His results agreed very well, he only saw a<br> small deviation for &Delta;2 in the lowest Q<sup>2</sup> range. To check that nothing strange was going <br> on in the low Q<sup>2</sup> range, he calculated &Delta;2 for various small ranges around zero, to ensure<br>that the integration method is well behaved. The Carlson paper also includes calculations <br>using the Simula model, he would like to do a check of this method as well, but is unsure <br>where to find the Simula model. Since he was able to reproduce the hyperfine splitting <br>result, he is confident in his calculation method; it should be straightforward to calculate <br>other spin structure function integrals. More details on his method can be found in his <br>slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_09215.pdf here].<br />
<br />
*Toby<br />
**Showed an update on his acceptance/scattering angle study. He applied cuts of varying<br>strictness on the reconstructed &theta; vs &phi; distribution at the target. He then calculated the <br>real scattering angle before/after scattering for each cut. Using these scattering angles <br> as inputs for the Bosted model he was able to calculate the XS and compare it to data.<br>He showed the comparison between data/Bosted model for each acceptance cut. He <br>hoped that the more extreme acceptance cuts on the data would flatten the yield <br>distribution, but it actually just enhanced the sawtooth pattern. JP questioned why the <br>Bosted prediction for one momentum bin (the green one) was so much lower than the<br> neighboring ones. Toby said the only input that goes into the model is the scattering angle,<br> so it must be considerably different for this momentum setting. He also commented that<br>the model prediction is scaled to match the data, so the scaling enhances the jump in<br>the model. More details on his acceptance cuts and method can be found in his slides<br>[http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/acceptance_scatangle.pdf here].<br />
<br />
<br />
==8/26/2015==<br />
<br />
Present: Jixie, Alex, Min, Kalyan, JP, Chao, Melissa <br><br />
By Phone: Vince, Jie, Ryan, Toby, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Chao<br />
**Gave an update on optics studies. Previously, he showed a comparison between optics data <br>and simulation where he cut on individual sieve holes. For this week, he included a cut on y <br>and dp that he didn't include previously. In the plot of &theta; vs y, JP pointed out that there were <br>additional tails on some sieve holes, Chao says these tails go away when the &phi; cut is <br>included. He showed a 2D plot of &theta; vs &phi;, along with the 1D projection of these variables. JP<br>commented that the data is more smeared out than the simulation, so it is difficult to compare <br>data with simulation results. It's possible that some of the smearing comes from events that <br>punch through the sieve slit and are not being cut out (the simulation currently assumes these <br>events are stopped by the sieve). Looking at the center hole, the data/simulation agree <br>reasonably well, but the agreement gets worse for holes on the edge of the sieve slit. Chao<br>will continue to look into this. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150826/Chao_WeeklyMeeting_08262015.pdf here].<br />
**He also mentioned that ~1 month ago he reported a problem with the [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150708/Chao_WeeklyMeeting_07082015.pdf BPM simulation].<br>He found it was actually a problem with the simulation itself, which has now been updated <br> to correct the problem.<br />
<br />
<br />
'''General Discussion:'''<br />
*Pengjia has submitted his BPM NIM paper.<br />
<br />
<br />
==8/19/2015==<br />
<br />
Present: Chao, Jie, Min, Jixie, Kalyan, Melissa <br><br />
By Phone: Vince, Ryan, Toby, Karl, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Showed a method for determining the correction to asymmetries for pion contamination. The <br>measured asymmetry can be written in terms of the electron and pion asymmetries, multiplied <br>by the fraction of events of that particle. To differentiate between electrons and pions, a cut is<br>made on events that trigger the Cherenkov detector (electrons) and events that do not trigger<br>the Cherenkov (pions). Kalyan commented that this method of selecting pions may be too blind,<br> and suggested making a 2D cut on E/p vs Cherenkov instead. To determine the fraction of<br>electrons/pions, "good event" cuts are applied (loose acceptance cuts, single track events and<br>pion rejector cuts) and the number of electrons/pions that survive the cuts are counted. Although<br>the pion asymmetry is much larger than the electron asymmetry, the number of residual pions<br>is very small, so the overall correction is small. For this example the 2.2 GeV, 5T longitudinal<br>setting was used, but the correction may be larger for the 5T transverse settings, which she <br>will do next. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Pion/PionAsym_08_19.pdf here].<br />
<br />
*Min <br />
**Gave an update on acceptance studies. She used the 1.7 GeV, 2.5T setting (with 3rd septum <br>configuration) to test the acceptance cuts using the yield ratio of data to simulation. She <br>showed a plot of target &theta; vs &phi; for both data and simulation, and applied a graphical cut to get<br>rid of events on the edges. Looking at the resulting 1D plots shows reasonable agreement<br>between &theta; and &phi;. Vince pointed out that there seems to be some additional structure in the<br>dp distribution, and suggested expanding the &delta; cut out to &pm; 4% to see if there is more <br>hidden structure. Min said she has seen this in other settings as well and will look into it. She<br>also tried adjusting the cuts on &theta;, &phi; and &delta; and looked at how the ratio of yields from data/<br>simulation changed; the ratio starts to drop off as the cuts get wider. Next she will work on<br>calculating the yields using W bins. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/08192015.pdf here].<br />
<br />
<br />
==8/12/2015==<br />
<br />
Present: Jie, Chao, Kalyan, Min, Jixie, Melissa <br><br />
By Phone: Pengjia, Ryan, Toby, Karl, Ellie, Alex <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Chao<br />
**Gave an update on optics studies. Previously, Min has shown comparisons of data/simulation<br> where she looked at different columns of sieve holes. Chao continued this study by cutting on <br>individual sieve holes. Looking at the center sieve hole, the &phi; distribution looks reasonable, but <br>the &theta; distribution has some issues. Specifically, the data is wider on the left side (negative &theta;) <br>than the simulation. He showed results for several sieve holes, including one that was in the <br>row as the center hole, but in the farthest column on the left side of the sieve slit. In this case <br>the &theta; distribution had similar width for both data and simulation, but the height of the simulation<br> distribution was larger. This may suggest that something is wrong with the acceptance in the <br>simulation. The problem with &theta; seems to be systematic; for most of the sieve holes there are <br>more events on the left side of the data than in the simulation. Kalyan asked whether the <br>thickness of the sieve slit was taken into account, Chao says it was included in the simulation <br>and optimizer. Jixie suggested comparing the dp distributions for each sieve hole. More details <br>can be seen in Chao's slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150812/Chao_WeeklyMeeting_08122015.pdf here].<br />
<br />
<br />
==7/29/2015==<br />
<br />
Present: Chao, Min, JP, Melissa <br><br />
By Phone: Alex, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Min<br />
**Gave an update on acceptance studies. Previously, Chao showed a correction for the beam<br>position in g2psim. Min checked this correction by looking at optics runs. On the data she <br>applied a cut on dp (to select elastic events) and on the focal plane (to get rid of junk <br> events). On the simulation, only an aperture cut was applied. She compared the data and<br>simulation results for &theta; and &phi; both before and after drifting from the sieve slit to the target.<br>The effect of the target field on &theta; is not very large, though there is a shift down in angle.<br>However, the shape of the &theta; distribution is different between data and simulation. The<br>effect of the target field on &phi; is significant; it's not clear why this is the case. To try to<br>determine the reason for the discrepancies, she applied a cut along each column of sieve<br>slit holes in &phi; and compared the data and simulation results for &theta;,&phi; and dp. Column 2<br>seems to have the best agreement (for dp), columns 1 and 2 have a shift while columns<br>3-6 have a difference in width. Chao suggested also cutting along each row of sieve slit<br>holes to better study the effect of the drift on &phi;. Min will work on identifying the differences<br>between data and simulation, specifically whether the boundaries are different between<br>the two. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07272015/07292015.pdf here].<br />
<br />
<br />
==7/22/2015==<br />
<br />
Present: JP, Min, Jixie, Melissa <br><br />
By Phone: Alex, Ryan, Toby, Ellie, Karl, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Showed various checks for packing fraction runs that have large discrepancies, including <br>beam position, beam energy, spectrometer central momentum setting, septum current, and<br>the location of anneals. For both the 2.2 and 1.1 GeV settings, there are significant shifts in <br>the x and y beam position (2mm or more). She showed the average and standard deviation <br> of epics readings for the LHRS septum current for each run. For several runs, there are small <br>number of epics readings that drift from the average current. It's not clear if this is the <br>current is actually changing or if it is a readout problem. She will look into the yield vs time<br>to try to determine this. JP suggested making a raster cut on the center of the beam to get<br> rid of any potential scraping. Pengjia says there is a way to cut on raster size, but there will<br> be an additional BPM uncertainty. Melissa will discuss this more offline with Pengjia. More<br>details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_07_22.pdf here].<br />
<br />
*Pengjia<br />
**Gave an update on calculating asymmetries/cross sections using the MAID model. This time, <br>he used the Bosted model to get the unpolarized cross sections for the proton. Using unradiated <br>cross section models, he still saw a factor of 6 difference when compared with data. Ryan also <br>calculated asymmetries using unradiated models, and the results were consistent with Pengjia's, <br>so it seems the radiative effects contribute significantly to the factor of 6 difference. More <br>details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07222015/MAID_update_20150722.pdf here].<br />
<br />
<br />
==7/15/2015==<br />
<br />
Present: JP, Min, Chao, Jixie, Melissa <br><br />
By Phone: Ryan, Toby, Ellie, Karl, Vince, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Chao<br />
**Doing a check of simulation/data results for the 2.2 GeV, longitudinal setting in order <br>to check that the optics calibration matrix will work for all momentum settings (not <br>just elastic). He showed a comparison for several different momentum settings.<br> Vince suggested simulating more events, since the statistics start to drop off for <br>lower momentum settings. In general, the data is broader then the result from<br>simulation. In the &theta; distribution, the "tails" seen in the data are not symmetric. JP<br> suggested carefully selecting cuts to remove any background from the data to <br>ensure a good comparison with simulation. More details can be seen in his <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150715/Chao_WeeklyMeeting_07152015.pdf here].<br />
<br />
*Pengjia<br />
**More discussion on Pengjia's [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07082015/MAID_update_20150708.pdf slides] from last week. Pengjia has seen a factor of <br>six difference between his asymmetry calculated from data compared to the <br>asymmetry determined using the MAID model. Ryan did not see this factor of six <br>in his study, but in addition to using radiated XS models, he is using a combination <br>of the Bosted and MAID models (Pengjia is using just the MAID model). Karl <br>commented that the XS from MAID is not very good for our kinematics. Pengjia <br>also showed an estimated NH3 XS. JP commented that it was surprising that the <br>delta peak wasn't visible. Pengjia will look into this for next time.<br />
<br />
<br />
==7/8/2015==<br />
<br />
Present: JP, Min, Chao, Melissa <br><br />
By Phone: Toby, Vince <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Pengjia<br />
**Working on comparing asymmetries determined from MAID to those calculated from <br>data; last time he showed a factor of 6 difference between the two results. This <br>time, he showed two different methods for calculating the differential XS from the <br>virtual photon XS. The first method calculates the differential XS directly from <br>the virtual photon XS, and the second method calculates the differential XS using <br>F<sub>1</sub>, F<sub>2</sub>, g<sub>1</sub> and g<sub>2</sub>. He also showed two different methods for calculating the <br>asymmetry from the virtual photon XS; one method uses A<sub>1</sub> and A<sub>2</sub>, while the other <br>is calculated from the virtual photon XS. There was a discrepancy between the two <br>methods, but he found that there was actually a mistake in one of the equations. <br>While the results from the two methods agree with each other, they are still a factor <br>of 6 larger than the results from data. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07082015/MAID_update_20150708.pdf here].<br />
<br />
*Toby<br />
**Showed an update of his scattering angle study for model reconstruction. He is <br>using BPM and optics data to determine the scattering angle. He showed an example <br>of the calculated scattering angle; JP questioned whether the range was really from <br>0-16 deg. Toby pointed out that there really aren't many events at the boundaries, <br>the distribution is peaked between 4.5-9 deg. He then uses this scattering angle as<br>input for the Bosted model. At low &nu; the simulation results match reasonably well<br>with the data, but the discrepancy starts to become larger as &nu; increases. He took <br>a closer look at the reconstructed scattering angle for each central momentum, and <br>found that a second peak is visible for smaller values of p0. If this second peak was <br>real, the simulation should recreate the data, so this could suggest a problem with <br>the reconstruction. However, Chao pointed out that, for this energy setting, the optics <br>calibration is not complete (currently using the longitudinal optics matrix), so the <br>reconstructed &theta; and &phi; may not be correct yet. For next time, Toby will test this <br>analysis using the 1.7 GeV setting, which has calibrated optics. More details can <br> be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/scatangle_talk.pdf here].<br />
<br />
*Melissa<br />
**Gave a summary of packing fraction analysis. For some settings, the variation in the <br>yields (and P<sub>f</sub>) is due to a fluctuation in the beam position. This will hopefully be<br>resolved by Jie's beam position/acceptance study. For the 2.2 GeV, 2.5T transverse setting<br> there is also an issue of a shift in &nu; between runs. For the 1.1 GeV, 2.5T transverse <br>setting, the yields vary depending on the beam current used for each run. JP suggested <br>a few things to check as the possible cause for these discrepancies including drift in the <br>BCM calibration, anneals of the target material, drift in field (HRS or septum), etc. She <br>has posted a technote draft [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Technotes/PF_technote_draft.pdf here], feedback would be appreciated. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_07_08.pdf here].<br />
<br />
*Min<br />
**Gave an update on her acceptance study. Last time, she showed that the simulation results <br>are more narrow than the data. For this time, she tried cutting on just the center hole, <br>and found that the dp distribution from data better matched the simulation. JP suggested <br>cutting on each of the different holes individually to determine which hole causes the dp <br>distribution to be wider. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07082015/07062015.pdf here].<br />
<br />
*Chao<br />
**Gave an update on optics analysis, currently checking whether simulation results match <br>with data, starting with optics data. First he checked whether the geometry was correct, <br>some deviation was found in the recent optics meeting. The position of the BPMs is hard-<br>coded into the simulation, and the drifting algorithm is used to drift the electrons <br>backward to the BPMs to simulate the readout of BPM A and B. He compared the &theta; <br>distribution before drifting in the target field using a fixed and non-fixed BPM location. <br>The results using a fixed BPM match well with the data. He is currently working on <br>checking this for all momentum settings, and will follow up with Pengjia about the BPM <br>problem. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150708/Chao_WeeklyMeeting_07082015.pdf here].<br />
<br />
<br />
==7/1/2015==<br />
<br />
Present: Chao, Vince, Jie, JP, Min, Melissa <br><br />
By Phone: Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Min<br />
**Gave an update on acceptance studies. She showed a summary table of each energy <br>setting and septum configuration. There hasn't been any problems in the 2.2 GeV, 5T <br>longitudinal and 1.7 GeV, 2.5T transverse settings, but some settings (2.2 GeV, 2.5T <br> transverse, 1.2 GeV, 2.5T transverse and 2.2 GeV, 5T transverse) have a discrepancy <br>in the focal plane between data and simulation. She compared the data divided by the <br>Mott XS to the simulation results without XS, and found that the simulation results <br>of &theta; and &phi; are narrower then the data. JP commented that, while including the Mott<br>XS might change the shape of the distribution, it shouldn't change the boundary. She <br>work on figuring out the cause for this discrepancy before calculating the acceptance. <br>More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07012015/07012015.pdf here].<br />
<br />
*Pengjia<br />
**Comparing asymmetries determined from the MAID model to those calculated from data.<br>Last time he showed a factor of 6 difference between the two results. He determined the <br>scattering angle and Q<sup>2</sup> by fitting the data and compared them to the quantities calculated <br>from MAID. He also showed the results of calculating the quantities g<sub>1</sub>, g<sub>2</sub>, F<sub>1</sub>, F<sub>2</sub>, A<sub>L</sub>, A<sub>T</sub>,<br> dXS<sub>L</sub>, dXS<sub>T</sub>, XS<sub>tot</sub> andXS<sub>mott</sub> using MAID. He hasn't included radiative corrections in his <br>calculations, but this probably won't account for the factor of 6. More details can be seen <br>in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07012015/MAID_20150701.pdf here].<br />
<br />
<br />
----<br />
<br />
==Jan-June 2015==<br />
[[Minutes_Jan2015_to_June2015]]<br />
----<br />
<br />
==July-Dec 2014==<br />
[[Minutes_July2014_to_Dec2014]]<br />
----<br />
<br />
==Jan-June 2014==<br />
[[Minutes_Jan2014_to_June2014]]<br />
----<br />
<br />
==June-Dec 2013==<br />
[[Minutes_June2013_to_Dec2013]]<br />
----<br />
<br />
==Jan-May 2013==<br />
[[Minutes_Jan2013_to_May2013]]<br />
----<br />
<br />
==April-Dec 2012==<br />
[[Minutes_Apr2012_to_Dec2012]]<br />
----<br />
<br />
==Jan-March 2012==<br />
[[Minutes_Jan2012_to_Mar2012]]<br />
----<br />
==July-Dec 2011==<br />
[[Minutes_July2011_to_Dec_2011]]<br />
----<br />
==Jan-June 2011==<br />
[[Minutes_Jan2011_to_June_2011]]<br />
----</div>Melissachttps://hallaweb.jlab.org/wiki/index.php?title=G2p_Analysis_Minutes&diff=26413G2p Analysis Minutes2015-12-09T14:22:15Z<p>Melissac: /* 11/18/2015 */</p>
<hr />
<div>Minutes of the weekly analysis meetings<br />
----<br />
[https://hallaweb.jlab.org/wiki/index.php/G2p_Weekly_Analysis Agenda]<br />
<br />
==11/25/2015==<br />
<br />
<br />
Present: JP, Kalyan, Min, Melissa <br><br />
By Phone: Vince, Jie, Toby, Ryan, Karl, Chao <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Showed updated "very preliminary" results for g1/g2. She tried to estimate the uncertainty on the <br>MAID model by comparing it with EG1B data for g1. She looked at the difference between the <br>model prediction and the EG1B results for their lowest values of Q2, and assigned a constant <br>uncertainty of 40% on the MAID model. JP suggested breaking the uncertainty up into different <br>regions, since the data in the delta region matches well with the model prediction but there is a <br>larger discrepancy for higher W. Karl questioned whether the enhancement in the longitudinal <br>asymmetry at large W is real, this will have to be considered carefully for the final analysis. More<br> details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/g1_g2/g1g2_11_25.pdf here].<br />
<br />
*Chao<br />
**Gave an update on the issue with the optics database. Toby showed last week that applying a <br>cut to phi resulted in structure in the dp distribution. Chao scanned the optics matrix to find the <br>element causing this issue, and found that the x^2 and x^3 elements of the phi tensor were causing <br>the over-fitting of the matrix. He showed the dp distribution without these two elements and the <br>unusual structure seen when a cut is placed on phi was gone. JP/Vince commented that it is troubling <br>that the x^2 dependence is causing a problem. They will discuss is more during the optics meeting. <br>More details can be seen in Chao's slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20151125/Chao_WeeklyMeeting_11252015.pdf here].<br />
<br />
<br />
==11/18/2015==<br />
<br />
<br />
Present: Min, JP, Melissa <br><br />
By Phone: Vince, Jie, Toby, Ryan, Karl, Ellie, Chao <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Toby<br />
**Gave an update on using the newest optics reconstruction matrix. He showed an example of one<br>run, located way past the delta resonance, so the dp distribution should be fairly flat. He tried <br>applying the phi cuts he has shown previously to remove acceptance and scattering angle effects,<br> but making a cut on phi revealed a strange structure in the dp spectrum. He showed the phi vs. dp <br>reconstruction both at the septum plane (i.e. without target effects) and after being reconstructed <br>back to the target. The strange structure exists in both distributions, so it is probably not a target <br>field effect. He is currently working with Chao to resolve this; Chao is doing a comparison of the <br>old and new databases to determine which element is causing this effect. More details can be seen <br>in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/updatedDB_acc.pdf here].<br />
**He has updated the target polarization uncertainties in the mysql. He will send out an email to the <br>collaboration with more details about this.<br />
<br />
*Pengjia<br />
**Showed the results of a study to check the effect of applying raster cuts on the yield. He showed <br>several examples of groups of runs where the yield was drifting. In some cases, the raster cuts <br>got rid of the drift in the yields, or at least made the drift significantly smaller. For one setting, the <br>raster cut did not resolve the change in yields, so there is likely something else causing the drift. <br>JP suggested doing some sanity check to confirm that the method works, such as starting with <br>a setting that has consistent yields and applying the raster cuts to see the effect. More details <br>can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/11182015/raster_cut_library.pdf here].<br />
<br />
==11/11/2015==<br />
<br />
Present: JP, Melissa <br><br />
By Phone: Vince, Toby, Ryan, Chao, Min, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Showed "very preliminary" results for g1/g2. She is using a dilution factor determined from <br>the Bosted model, and using the average value of the packing fraction for each material. For the <br>radiative corrections, she is using a model prediction for the asymmetry where the polarized piece <br>comes from the MAID model and the unpolarized cross section is the Bosted model. The difference <br>between the model prediction ''without'' radiative effects and the model prediction ''with'' radiative effects <br>is used as an additive correction to the asymmetry. There was some concern over the large effect <br>of the R.C. at high W. Ryan commented that the final R.C will be large, so they will need to be done<br>very carefully. A cross check with EG1 data will be helpful. In order to match the kinematics of the<br>longitudinal and transverse settings, she scaled the asymmetry by the ratio of the unpolarized cross<br>section at the two different kinematic settings. JP commented that this is not valid, and suggested <br>using model input for the asymmetries, instead of trying to match the kinematics between the data<br>taken in the longitudinal and transverse settings. Next she will work on updating systematics for the <br>asymmetries and structure functions. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/g1_g2/g1g2_11_10.pdf here].<br />
<br />
*Chao<br />
**Gave an update on optics analysis. Comparisons of the data with simulation revealed that there <br>were offsets in the reconstructed kinematics. This correction could be fixed using a finely-tuned<br>fitting procedure. The longitudinal setting has already been fixed, today he showed the results <br>for the 1.7 GeV, transverse setting. He showed the results of doing the calibration; most of the <br>holes near the center have a difference of less than 0.5 MeV between data and simulation. He is <br>currently working on finishing the other transverse settings. More details can be found in his <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20151111/Chao_WeeklyMeeting_11112015.pdf here].<br />
<br />
==11/4/2015==<br />
<br />
Present: Min, Jixie, Melissa <br><br />
By Phone: Chao, Vince, Toby, Ryan, Alex, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Ryan<br />
**Gave an overview of g2p elastic tail and angle reconstruction. The elastic tail is highly sensitive<br>to the scattering angle, so his goal is to develop a method to include these variations in the elastic <br>tail subtraction. He started by looking at the simplest case, helium dilution runs. Using his method, <br>he looked at the elastic tail across a series of different momentum settings, andfound that the tail <br>was not continuous, which he assumed was due to variations in the scattering angle. He did a pseudo-<br>simulation using the Bosted model and varying the scattering angle to confirm the "jump" seen in the <br>elastic tail. However, when he looked at the normalized yields for this same data, he did not see the <br>same discontinuity. This suggests there might be a problem with the scattering angle reconstruction. <br>Chao mentioned that the reconstruction code has been updated (at least for the longitudinal setting) <br>the last replay; he will provide this code to Toby so he can do another replay. Details of the method <br>and cuts used can be seen in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_11415.pdf here].<br />
<br />
*Jie<br />
**Gave an update on his simulation study to understand the beam dependence on the yields. He used the <br>beam position and raster size as input to g2psim, and included radiative and acceptance effects. In <br>general, he found there is a much larger dependence on the beam position using a rastered beam <br>compared to a point beam. He summarized his results for various different momentum settings and found <br>that, in some cases, his results matched what we saw in the data, but not in all cases. Vince suggested <br>testing how much the beam position would need to be changed (for a given momentum setting) to match <br>the simulation with the data. The details of his study can be found in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/yields_update_2015_11_04.pdf here], he is also compiling <br>a technote on this analysis.<br />
<br />
==10/28/2015==<br />
<br />
Present: JP, Min, Kalyan, Melissa <br><br />
By Phone: Alexandre, Vince, Jie, Ryan, Toby, Ellie, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Gave an overview of contributions to the systematic uncertainty for the asymmetry. There are <br>several contributions which are very small (<0.1%) including the charge asymmetry, livetime <br>asymmetry and pion contamination. The target polarization uncertainty was surprisingly small.<br>The values currently listed in the mysql DB for this quantity appear to be incorrect; Toby will<br>update these values. For the contribution from the dilution factor and radiative corrections, she<br> assigned 5% as a placeholder until a better estimate could be made. Karl/Ryan commented <br>that 5% uncertainty on the radiative corrections may be too small, 10-15% would be a better<br>estimate at this point. The tables shown for the longitudinal and transverse settings represent<br>an overestimate of the uncertainty; in the long-term this could be looked at more carefully to<br>decrease the overall systematic uncertainty. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Asym/Asym_10_28.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*There has been a request from the Hall A CC to have an update on g2p at the winter collaboration <br>meeting. Ellie and Jie are both interested, they will check the dates of the meetings to see if they <br>are available.<br />
<br />
==10/14/2015==<br />
<br />
Present: JP, Min, Jixie, Kalyan, Melissa <br><br />
By Phone: Alexandre, Vince, Jie, Todd, Haiyan, Pengjia, Karl, Toby, Ryan, Xiaochao, Nilanga, Chao <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Karl<br />
**Went over the goals of the collaboration meeting:<br />
***Discuss physics topics for students graduating soon<br />
***Identify major remaining physics topics<br />
***Establish a policy for the release of plots<br />
**Suggested a policy for collaboration release of physics results, including specific requirements <br>for moving from "very preliminary" to "preliminary" to "final" results. Details can be seen in his <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/slifer/2015/slifer_g2pcollab_101415.pdf here], and they will be circulated to the g2p mailing list with some small modifications.<br />
<br />
*Pengjia<br />
**Will be defending next Wednesday (Oct. 21st). He showed a "very preliminary" physics <br> asymmetry for the 2.2 GeV 5T setting (both longitudinal and transverse) with a comparison to <br> a radiated model prediction. He used this result to extract a preliminary value for g1 and g2,<br>using the Bosted model as input for the cross section. This result does not include radiative<br>corrections. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/graduate_2015.pdf here].<br />
<br />
*Min<br />
**Showed an overview of status of acceptance study; the overall goal is to match the simulation<br>results to the data, so that the simulation can be used to calculate the acceptance. She<br>described the various attempts to correct the simulation results to match the data. Adjusting the<br> apertures based on optics data works well, but the other two methods (adjusting the apertures <br>based on dilution data and adjusting the acceptance cuts after removing the Mott XS from the <br>data) only work well around the target run. In addition, the simulated yield has a different shape <br>than the data, so the simulation must be adjusted to match this. She will go through this process <br>again once Chao is finished with the optics correction. She is planning to graduate next January, <br>and would like to include a cross section difference for one kinematic setting in her thesis. More <br>details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/collab/10142015_collab_Min.pdf here].<br />
<br />
*Melissa<br />
**Gave an overview of packing fraction analysis. Of the 5 total settings there are 3 that are reasonably <br>stable with some small drifts in yields, and 2 settings that have larger problems. During the 2.2 GeV, <br>2.5T setting the raster size was changed, which could possibly be corrected by applying a cut on<br>the center of the raster. The 1.1 GeV setting has large variations in the elastic yields; some of these <br>runs were taken at low currents (8-20nA), so the beam position information is not reliable. She also <br>showed the results of a pion asymmetry study. Although the pion asymmetry is very large, the <br>residual pion contamination after PID cuts are applied is very small, so the correction is not large. <br>She has scheduled her defense for December 4th, and would like to include a preliminary result <br>for g1,g2 in her thesis. To include a fully corrected result she will need preliminary radiative <br>corrections and dilution results, which she will work with Ryan and Toby to get. More details can <br>be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/talks/MCummings_CollabMeeting_20151013.pdf here].<br />
<br />
*Toby<br />
**Showed a preliminary dilution value that he had shown previously, and described several issues <br>with the result. These issues include that the model assumes a constant scattering angle, and does <br>not include some acceptance effects that are seen in the data. He has been working on correcting <br>these issues by incorporating a scattering angle from data into the model and applying acceptance <br>cuts to the data to remove acceptance effects. He showed the result of applying the acceptance cut <br>across all kinematics for the 5T longitudinal setting; including the acceptance cut gets rid of some of <br>the strange structure seen in the yields, such as the sawtooth pattern seen at high nu. The downside <br>of this method is that the acceptance cut causes a large loss in statistics. He is currently working on <br>trying to re-incorporate some of the lost statistics from the acceptance cut. More details can be seen <br>in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/collaborationupdate.pdf here].<br />
<br />
*Jie<br />
**Gave an update on his study using simulation to understand the drifts in yields. He looked at several <br>momentum settings in the 2.2 GeV, 2.5T setting that had variation in the yields. He varied the beam <br>position along the horizontal and vertical directions using both a point beam and rastered beam. He <br>generated a table summarizing the results using a Monte Carlo method, cross checking with averaged <br>acceptance. His results were similar to his previous test using only the Bosted model; some results <br>agree with what was seen in the data, some have the opposite sign. He will write up his method and <br>results in a technote. He is planning to graduate in summer of 2016. More details can be seen in his <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_10_09_simulation/2015_10_14_collaboration_meeting.pdf here].<br />
<br />
*Chao<br />
**Gave an update on optics analysis. Comparisons of simulation with data revealed that the <br>reconstructed kinematics have some offset. A correction was added to the reconstructed kinematics <br>(vs beam position) and he is currently working on merging this correction into the database with a <br>finely tuned fitting procedure. The problem is that the horizontal beam position shifts the dp <br>reconstruction. He showed the results of applying the new optics matrix which corrects for this shift. <br> He will apply this method to all kinematic settings and study the uncertainty of the optics. Once this <br>is done he will write a NIM paper for g2p optics. He plans to graduate in February/March and would <br>like to include the cross section difference for one or two settings with tuned acceptance and model <br>inputs to obtain a physics result. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20151014/Chao_WeeklyMeeting_10142015.pdf here].<br />
<br />
*Ryan<br />
**Since the last collaboration meeting he has improved the model tuning procedure by using an <br>automated procedure instead of tuning the model by hand. He has tested this using carbon data <br>from the UVa database and will run it for nitrogen data once he has updated saGDH N2 cross <br>sections from Vince. He also updated the systematic error study for inelastic unpolarized radiative <br>corrections by separating the integration/iteration error from the interpolation error. He has the <br>polarized radiative correction code running, and has completed a systematic uncertainty study on <br>the inelastic radiative corrections. He is also working on evaluating physics quantities using models, <br>specifically the hyperfine splitting calculation. He plans to graduate in summer/fall of 2016 and would <br>like to include full radiative corrections on g2p polarized cross sections in his thesis. More details can<br> be seen in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_101315.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*Important to do cross checks of results between students (ex. asymmetries)<br />
*Must be careful to include details of any physics results (whether radiative corrections are included,<br>dilution factor, model input instead of data, etc.)<br />
<br />
==9/30/2015==<br />
<br />
Present: JP, Kalyan, Jixie, Min <br><br />
By Phone: Pengjia, Toby, Ryan, Vince, Jie, Chao, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Toby<br />
**Showed an update on his acceptance/dilution study. He continued with the study of the cuts on the <br>reconstructed &theta; vs &phi; distribution at the target. He scanned several different &theta; vs &phi; cuts to see how <br>the acceptance effects the scattering angle and resulting yields. It turns out the small angle region is <br>influenced by the acceptance a lot but the center region gives a good agreement to the model. He <br>also loosed the center cut to &theta; ~ ± 40 mrad and &phi; ~ ± 10 mrad, the data still agreed with the model. <br>He then recalculated the dilution factor for 2.254 GeV longitudinal setting. More details on his <br>acceptance cuts and method can be found in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/diltalk_093015.pdf here].<br />
<br />
<br />
==9/23/2015==<br />
<br />
Present: JP, Kalyan, Min, Melissa <br><br />
By Phone: Pengjia, Toby, Ryan, Vince, Jie, Chao, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Pengjia<br />
**Showed the structure of his code to create a radiated model of the MAID and Bosted <br>models, based on Ryan's radiative correction work. He showed the breakdown of the <br>different components to the radiated model (internal, external and elastic tail). He used<br> the radiated model to calculate an asymmetry and cross section differences, which he <br> compared with data. Finally, he combined asymmetries calculated from data with the <br>Bosted model cross section to calculate a value for g1 and g2, which he compared <br>with values of g1/g2 determined using the MAID model. More details can be seen in <br>his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/09222015/asym_g12.pdf here].<br />
<br />
*Min<br />
**Gave an update on acceptance studies. Last time, she found that by adjusting the<br>apertures in the simulation she could match the data/simulation results for dp (for one <br>momentum setting). She tested this method for other momentum settings and found <br>that it did not work as well. She also showed a comparison of the yield spectrum for<br>helium runs in the 1.7 GeV setting; the shape of the two distributions are quite <br>different, which might suggest that the model deviates significantly form the data. In<br>the simulated results she saw several "bumps" in the yield, which correspond to the<br>location of resonances. She will update these results when the optics corrections are <br>complete. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/09232015.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*We would like to schedule another collaboration meeting in the near future. The <br>meeting is tentatively scheduled for Wednesday October 14th during our usual meeting <br>time (10am-12pm).<br />
*The purpose of the meeting is to:<br />
**Discuss student thesis topics (particularly any updates from the last <br>collaboration meeting)<br />
**Establish a procedure for presentation/release of collaboration plots/results<br />
*Each student should prepare a few slides (~5 minutes) to show analysis progress<br />
<br />
<br />
==9/16/2015==<br />
<br />
Present: Min, JP, Jixie, Melissa <br><br />
By Phone: Vince, Jie, Chao, Pengjia, Alex, Ryan, Toby, Ellie <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Jie<br />
**Gave an update on his simulation study using MUDIFI. Last time he showed that he uses a<br>least square fit to go from endplane to endplane. For the g2p simulation, it's used to go from<br>(x,y,&theta;,&phi;,dp) in the target plane to (x,y,&theta;,&phi;,dp) in the focal plane. SNAKE produces (x,y,&theta;,&phi;,dp)<br>data in both planes and a polynomial function can be used to determine the relationship<br>between the two planes. First the maximum power for each variable is determined, symmetries<br>are included (if applicable), then the priority of each function must be determined. A Gram-<br>Schmidt transformation is used to do the minimization, and the final step is to decide whether<br>to accept the function f<sub>i</sub>. JP/Vince asked how the priority for each function is chosen, since the<br>choice could introduce some ordering dependence. Since we don't have enough data to<br>constrain, JP suggested introducing some physics. He also suggested getting rid of dp in the<br>focal plane (since it is really just dp in the target plane) so that there is one less dimension to<br>fit. More details can be seen in Jie's slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_09_15_simulation/2015_09_15_Simulation_update.pdf here].<br />
<br />
*Ryan<br />
**Gave an update on evaluating physics quantities using models. His goal was to do a<br>comparison of the hyperfine splitting calculation in C. Carlson's 2006/2008 paper using MAID<br>and Hall B models. Previously he showed a comparison using the Hall B model, where he saw<br>good agreement between his calculation and Carlson's result. For this time he also did a<br>comparison using the MAID model. There is a large difference between the two models for the<br>value of the integrand of &Delta;<sub>2</sub>, over the full range of Q<sup>2</sup>. JP suggested comparing the value of g2<br>between the two models, instead of &Delta;<sub>2</sub>. More details can be seen in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_091615.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*Toby<br />
**Last time he showed a comparison between data and cross sections calculated using the<br>Bosted model (seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/acceptance_scatangle.pdf here]). The model was not continuous for one momentum setting. It <br>turns out the BPM was not recording for that setting, so he re-calculated the XS using<br>values for &theta; and &phi; from surrounding runs and found that the result was now consistent with<br>the neighboring momentum settings. He also played around with the acceptance cuts he<br>showed, and found a region using the "extreme cut" where the sawtooth pattern go away<br>and the yields become flat.<br />
<br />
<br />
==9/9/2015==<br />
<br />
Present: Min, JP, Jixie, Melissa <br><br />
By Phone: Vince, Jie, Chao, Ryan, Toby, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Jie<br />
**Gave an overview of his simulation study using SNAKE and MUDIFI. Using SNAKE, the<br>idea is to trace the particle trajectory in a series of free boxes, then an endplane can be<br>defined within the free boxes to determine the trajectory from endplane to endplane. In<br>g2psim this will be used to trace the trajectory between the sieve plane and the focal<br>plane. There are two important issues to consider, the magnetic field in the free boxes,<br>and the transportation method between the two endplanes. A Runge-Kutta method is <br>used for the transportation, and an adaptive method (which changes with field size and<br>gradient) is used to determine the step size. For the magnetic field, a 3D Tosca field<br>map is used for the septum, and an analytic model is used for the spectrometer magnets. <br> He also described the method for choosing the transportation function to determine the <br>25 matrix terms for each kinematic variable (up to 4th order). JP asked how to determine <br>which order is more important, and cautioned to be careful not to over fit the data. He and<br>Jie will discuss this more offline. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_09_09_simulation_update/2015_09_09_Simulation%20update.pdf here].<br />
<br />
*Chao<br />
**Gave an optics status update. The current problem is that changes in the horizontal beam<br>position changes the dp reconstruction. This was fixed by applying a linear correction in<br>BPM-x and BPM-y to &theta;, &phi; and dp. Applying this correction made the data/simulation <br>agree, but it is still necessary to understand the correction. Using dp scan data with beam<br>position scan data still leaves an offset in &theta; and &phi;. He also tried two other methods to do<br>the calibration. Method 1 uses the central hole to determine a constant offset, uses the<br>horizontal beam position scan data to determine all the matrix elements related to y, and<br>uses dp scan runs to fit the additional matrix elements. Method 2 uses beam position<br>scan data to determine the matrix elements that are not related to x<sub>fp</sub>. Neither of these<br>methods works very well, even when the fitting order of the matrix elements are adjusted.<br>He will continue to check more fitting procedures. More details can be found in his slides <br>[http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150909/Chao_WeeklyMeeting_09092015.pdf here].<br />
<br />
*Pengjia<br />
**Gave an update on comparing asymmetries from data/models for the 2.2 GeV, 5T <br>longitudinal setting. He first radiated the Bosted model XS; he showed the break down of<br>the different radiative corrections including the elastic tail (internal and external) and the<br>radiative effects from inelastic scattering. He showed a comparison with Ryan's results<br>which had good agreement, though there is some deviation when he used different proton<br>form factors (provided by Moshe). In order to compare the asymmetry result with data, he<br>needs to do the radiative corrections for the polarized MAID model, which he will continue<br>to work on. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/09092015/asym_20150909.pdf here].<br />
<br />
<br />
==9/2/2015==<br />
<br />
Present: JP, Min, Kalyan, Melissa <br><br />
By Phone: Vince, Alex, Jie, Chao, Ryan, Toby, Ellie, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Gave an update on determining the correction to asymmetries for pion contamination. <br>Previously, she used the 2.2 GeV, 5T longitudinal setting as an example, for this time <br>she used the transverse configuration, as it has the largest pion contamination. She <br>modified her method for differentiating between electrons and pions; previously she <br>identified pions as events that do not trigger the Cherenkov, this time she used a cut <br>below the single photo electron peak to select pions. JP suggested using stricter cuts <br>for selecting pions when determining the pion asymmetry, to make sure it is a clean <br>sample. Although this setting has a large pion contamination, the number of pion<br> events that remain after lead glass cuts are applied is low, so the overall correction <br>is very small. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Pion/PionAsym_08_31.pdf here].<br />
<br />
*Min<br />
**Gave an update on acceptance tuning. She looked at results from the 1.7 GeV setting <br>and found that the height of the peaks is different between data and simulation for <br>different holes in the sieve slit. Looking at the &theta; vs &phi; distribution, she noticed on the<br>positive &theta; side there were fewer holes in simulation than in data, and on the negative <br> &theta; side there were more holes in simulation compared to data. She tried adjusting the<br>aperture cuts by changing the physical location of the Q1, Q2 and septum planes to <br>uncover events that were previously blocked. After the adjustment, the data/simulation <br>results agreed much better. She showed a similar procedure for a dilution run and was<br>able to see better agreement between data/simulation after the aperture adjustments <br>were made. JP/Vince suggested being cautious when adjusting the aperture cuts, as<br> the apertures should be well defined already. They suggested adjusting things that are<br> less well known first, such as the septum field. More details can be seen in her slides<br>[http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/09022015.pdf here].<br />
<br />
*Ryan<br />
**Working on generating physics quantities using models to eventually compare with data.<br>So far, he has incorporated the MAID2007 and Hall B models. He calculated the <br>hyperfine splitting quantities &Delta;1 and &Delta;2 using the Hall B EG1 model and compared them<br> to the results in C. Carlson's 2006 paper. His results agreed very well, he only saw a<br> small deviation for &Delta;2 in the lowest Q<sup>2</sup> range. To check that nothing strange was going <br> on in the low Q<sup>2</sup> range, he calculated &Delta;2 for various small ranges around zero, to ensure<br>that the integration method is well behaved. The Carlson paper also includes calculations <br>using the Simula model, he would like to do a check of this method as well, but is unsure <br>where to find the Simula model. Since he was able to reproduce the hyperfine splitting <br>result, he is confident in his calculation method; it should be straightforward to calculate <br>other spin structure function integrals. More details on his method can be found in his <br>slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_09215.pdf here].<br />
<br />
*Toby<br />
**Showed an update on his acceptance/scattering angle study. He applied cuts of varying<br>strictness on the reconstructed &theta; vs &phi; distribution at the target. He then calculated the <br>real scattering angle before/after scattering for each cut. Using these scattering angles <br> as inputs for the Bosted model he was able to calculate the XS and compare it to data.<br>He showed the comparison between data/Bosted model for each acceptance cut. He <br>hoped that the more extreme acceptance cuts on the data would flatten the yield <br>distribution, but it actually just enhanced the sawtooth pattern. JP questioned why the <br>Bosted prediction for one momentum bin (the green one) was so much lower than the<br> neighboring ones. Toby said the only input that goes into the model is the scattering angle,<br> so it must be considerably different for this momentum setting. He also commented that<br>the model prediction is scaled to match the data, so the scaling enhances the jump in<br>the model. More details on his acceptance cuts and method can be found in his slides<br>[http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/acceptance_scatangle.pdf here].<br />
<br />
<br />
==8/26/2015==<br />
<br />
Present: Jixie, Alex, Min, Kalyan, JP, Chao, Melissa <br><br />
By Phone: Vince, Jie, Ryan, Toby, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Chao<br />
**Gave an update on optics studies. Previously, he showed a comparison between optics data <br>and simulation where he cut on individual sieve holes. For this week, he included a cut on y <br>and dp that he didn't include previously. In the plot of &theta; vs y, JP pointed out that there were <br>additional tails on some sieve holes, Chao says these tails go away when the &phi; cut is <br>included. He showed a 2D plot of &theta; vs &phi;, along with the 1D projection of these variables. JP<br>commented that the data is more smeared out than the simulation, so it is difficult to compare <br>data with simulation results. It's possible that some of the smearing comes from events that <br>punch through the sieve slit and are not being cut out (the simulation currently assumes these <br>events are stopped by the sieve). Looking at the center hole, the data/simulation agree <br>reasonably well, but the agreement gets worse for holes on the edge of the sieve slit. Chao<br>will continue to look into this. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150826/Chao_WeeklyMeeting_08262015.pdf here].<br />
**He also mentioned that ~1 month ago he reported a problem with the [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150708/Chao_WeeklyMeeting_07082015.pdf BPM simulation].<br>He found it was actually a problem with the simulation itself, which has now been updated <br> to correct the problem.<br />
<br />
<br />
'''General Discussion:'''<br />
*Pengjia has submitted his BPM NIM paper.<br />
<br />
<br />
==8/19/2015==<br />
<br />
Present: Chao, Jie, Min, Jixie, Kalyan, Melissa <br><br />
By Phone: Vince, Ryan, Toby, Karl, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Showed a method for determining the correction to asymmetries for pion contamination. The <br>measured asymmetry can be written in terms of the electron and pion asymmetries, multiplied <br>by the fraction of events of that particle. To differentiate between electrons and pions, a cut is<br>made on events that trigger the Cherenkov detector (electrons) and events that do not trigger<br>the Cherenkov (pions). Kalyan commented that this method of selecting pions may be too blind,<br> and suggested making a 2D cut on E/p vs Cherenkov instead. To determine the fraction of<br>electrons/pions, "good event" cuts are applied (loose acceptance cuts, single track events and<br>pion rejector cuts) and the number of electrons/pions that survive the cuts are counted. Although<br>the pion asymmetry is much larger than the electron asymmetry, the number of residual pions<br>is very small, so the overall correction is small. For this example the 2.2 GeV, 5T longitudinal<br>setting was used, but the correction may be larger for the 5T transverse settings, which she <br>will do next. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Pion/PionAsym_08_19.pdf here].<br />
<br />
*Min <br />
**Gave an update on acceptance studies. She used the 1.7 GeV, 2.5T setting (with 3rd septum <br>configuration) to test the acceptance cuts using the yield ratio of data to simulation. She <br>showed a plot of target &theta; vs &phi; for both data and simulation, and applied a graphical cut to get<br>rid of events on the edges. Looking at the resulting 1D plots shows reasonable agreement<br>between &theta; and &phi;. Vince pointed out that there seems to be some additional structure in the<br>dp distribution, and suggested expanding the &delta; cut out to &pm; 4% to see if there is more <br>hidden structure. Min said she has seen this in other settings as well and will look into it. She<br>also tried adjusting the cuts on &theta;, &phi; and &delta; and looked at how the ratio of yields from data/<br>simulation changed; the ratio starts to drop off as the cuts get wider. Next she will work on<br>calculating the yields using W bins. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/08192015.pdf here].<br />
<br />
<br />
==8/12/2015==<br />
<br />
Present: Jie, Chao, Kalyan, Min, Jixie, Melissa <br><br />
By Phone: Pengjia, Ryan, Toby, Karl, Ellie, Alex <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Chao<br />
**Gave an update on optics studies. Previously, Min has shown comparisons of data/simulation<br> where she looked at different columns of sieve holes. Chao continued this study by cutting on <br>individual sieve holes. Looking at the center sieve hole, the &phi; distribution looks reasonable, but <br>the &theta; distribution has some issues. Specifically, the data is wider on the left side (negative &theta;) <br>than the simulation. He showed results for several sieve holes, including one that was in the <br>row as the center hole, but in the farthest column on the left side of the sieve slit. In this case <br>the &theta; distribution had similar width for both data and simulation, but the height of the simulation<br> distribution was larger. This may suggest that something is wrong with the acceptance in the <br>simulation. The problem with &theta; seems to be systematic; for most of the sieve holes there are <br>more events on the left side of the data than in the simulation. Kalyan asked whether the <br>thickness of the sieve slit was taken into account, Chao says it was included in the simulation <br>and optimizer. Jixie suggested comparing the dp distributions for each sieve hole. More details <br>can be seen in Chao's slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150812/Chao_WeeklyMeeting_08122015.pdf here].<br />
<br />
<br />
==7/29/2015==<br />
<br />
Present: Chao, Min, JP, Melissa <br><br />
By Phone: Alex, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Min<br />
**Gave an update on acceptance studies. Previously, Chao showed a correction for the beam<br>position in g2psim. Min checked this correction by looking at optics runs. On the data she <br>applied a cut on dp (to select elastic events) and on the focal plane (to get rid of junk <br> events). On the simulation, only an aperture cut was applied. She compared the data and<br>simulation results for &theta; and &phi; both before and after drifting from the sieve slit to the target.<br>The effect of the target field on &theta; is not very large, though there is a shift down in angle.<br>However, the shape of the &theta; distribution is different between data and simulation. The<br>effect of the target field on &phi; is significant; it's not clear why this is the case. To try to<br>determine the reason for the discrepancies, she applied a cut along each column of sieve<br>slit holes in &phi; and compared the data and simulation results for &theta;,&phi; and dp. Column 2<br>seems to have the best agreement (for dp), columns 1 and 2 have a shift while columns<br>3-6 have a difference in width. Chao suggested also cutting along each row of sieve slit<br>holes to better study the effect of the drift on &phi;. Min will work on identifying the differences<br>between data and simulation, specifically whether the boundaries are different between<br>the two. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07272015/07292015.pdf here].<br />
<br />
<br />
==7/22/2015==<br />
<br />
Present: JP, Min, Jixie, Melissa <br><br />
By Phone: Alex, Ryan, Toby, Ellie, Karl, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Showed various checks for packing fraction runs that have large discrepancies, including <br>beam position, beam energy, spectrometer central momentum setting, septum current, and<br>the location of anneals. For both the 2.2 and 1.1 GeV settings, there are significant shifts in <br>the x and y beam position (2mm or more). She showed the average and standard deviation <br> of epics readings for the LHRS septum current for each run. For several runs, there are small <br>number of epics readings that drift from the average current. It's not clear if this is the <br>current is actually changing or if it is a readout problem. She will look into the yield vs time<br>to try to determine this. JP suggested making a raster cut on the center of the beam to get<br> rid of any potential scraping. Pengjia says there is a way to cut on raster size, but there will<br> be an additional BPM uncertainty. Melissa will discuss this more offline with Pengjia. More<br>details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_07_22.pdf here].<br />
<br />
*Pengjia<br />
**Gave an update on calculating asymmetries/cross sections using the MAID model. This time, <br>he used the Bosted model to get the unpolarized cross sections for the proton. Using unradiated <br>cross section models, he still saw a factor of 6 difference when compared with data. Ryan also <br>calculated asymmetries using unradiated models, and the results were consistent with Pengjia's, <br>so it seems the radiative effects contribute significantly to the factor of 6 difference. More <br>details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07222015/MAID_update_20150722.pdf here].<br />
<br />
<br />
==7/15/2015==<br />
<br />
Present: JP, Min, Chao, Jixie, Melissa <br><br />
By Phone: Ryan, Toby, Ellie, Karl, Vince, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Chao<br />
**Doing a check of simulation/data results for the 2.2 GeV, longitudinal setting in order <br>to check that the optics calibration matrix will work for all momentum settings (not <br>just elastic). He showed a comparison for several different momentum settings.<br> Vince suggested simulating more events, since the statistics start to drop off for <br>lower momentum settings. In general, the data is broader then the result from<br>simulation. In the &theta; distribution, the "tails" seen in the data are not symmetric. JP<br> suggested carefully selecting cuts to remove any background from the data to <br>ensure a good comparison with simulation. More details can be seen in his <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150715/Chao_WeeklyMeeting_07152015.pdf here].<br />
<br />
*Pengjia<br />
**More discussion on Pengjia's [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07082015/MAID_update_20150708.pdf slides] from last week. Pengjia has seen a factor of <br>six difference between his asymmetry calculated from data compared to the <br>asymmetry determined using the MAID model. Ryan did not see this factor of six <br>in his study, but in addition to using radiated XS models, he is using a combination <br>of the Bosted and MAID models (Pengjia is using just the MAID model). Karl <br>commented that the XS from MAID is not very good for our kinematics. Pengjia <br>also showed an estimated NH3 XS. JP commented that it was surprising that the <br>delta peak wasn't visible. Pengjia will look into this for next time.<br />
<br />
<br />
==7/8/2015==<br />
<br />
Present: JP, Min, Chao, Melissa <br><br />
By Phone: Toby, Vince <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Pengjia<br />
**Working on comparing asymmetries determined from MAID to those calculated from <br>data; last time he showed a factor of 6 difference between the two results. This <br>time, he showed two different methods for calculating the differential XS from the <br>virtual photon XS. The first method calculates the differential XS directly from <br>the virtual photon XS, and the second method calculates the differential XS using <br>F<sub>1</sub>, F<sub>2</sub>, g<sub>1</sub> and g<sub>2</sub>. He also showed two different methods for calculating the <br>asymmetry from the virtual photon XS; one method uses A<sub>1</sub> and A<sub>2</sub>, while the other <br>is calculated from the virtual photon XS. There was a discrepancy between the two <br>methods, but he found that there was actually a mistake in one of the equations. <br>While the results from the two methods agree with each other, they are still a factor <br>of 6 larger than the results from data. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07082015/MAID_update_20150708.pdf here].<br />
<br />
*Toby<br />
**Showed an update of his scattering angle study for model reconstruction. He is <br>using BPM and optics data to determine the scattering angle. He showed an example <br>of the calculated scattering angle; JP questioned whether the range was really from <br>0-16 deg. Toby pointed out that there really aren't many events at the boundaries, <br>the distribution is peaked between 4.5-9 deg. He then uses this scattering angle as<br>input for the Bosted model. At low &nu; the simulation results match reasonably well<br>with the data, but the discrepancy starts to become larger as &nu; increases. He took <br>a closer look at the reconstructed scattering angle for each central momentum, and <br>found that a second peak is visible for smaller values of p0. If this second peak was <br>real, the simulation should recreate the data, so this could suggest a problem with <br>the reconstruction. However, Chao pointed out that, for this energy setting, the optics <br>calibration is not complete (currently using the longitudinal optics matrix), so the <br>reconstructed &theta; and &phi; may not be correct yet. For next time, Toby will test this <br>analysis using the 1.7 GeV setting, which has calibrated optics. More details can <br> be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/scatangle_talk.pdf here].<br />
<br />
*Melissa<br />
**Gave a summary of packing fraction analysis. For some settings, the variation in the <br>yields (and P<sub>f</sub>) is due to a fluctuation in the beam position. This will hopefully be<br>resolved by Jie's beam position/acceptance study. For the 2.2 GeV, 2.5T transverse setting<br> there is also an issue of a shift in &nu; between runs. For the 1.1 GeV, 2.5T transverse <br>setting, the yields vary depending on the beam current used for each run. JP suggested <br>a few things to check as the possible cause for these discrepancies including drift in the <br>BCM calibration, anneals of the target material, drift in field (HRS or septum), etc. She <br>has posted a technote draft [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Technotes/PF_technote_draft.pdf here], feedback would be appreciated. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_07_08.pdf here].<br />
<br />
*Min<br />
**Gave an update on her acceptance study. Last time, she showed that the simulation results <br>are more narrow than the data. For this time, she tried cutting on just the center hole, <br>and found that the dp distribution from data better matched the simulation. JP suggested <br>cutting on each of the different holes individually to determine which hole causes the dp <br>distribution to be wider. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07082015/07062015.pdf here].<br />
<br />
*Chao<br />
**Gave an update on optics analysis, currently checking whether simulation results match <br>with data, starting with optics data. First he checked whether the geometry was correct, <br>some deviation was found in the recent optics meeting. The position of the BPMs is hard-<br>coded into the simulation, and the drifting algorithm is used to drift the electrons <br>backward to the BPMs to simulate the readout of BPM A and B. He compared the &theta; <br>distribution before drifting in the target field using a fixed and non-fixed BPM location. <br>The results using a fixed BPM match well with the data. He is currently working on <br>checking this for all momentum settings, and will follow up with Pengjia about the BPM <br>problem. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150708/Chao_WeeklyMeeting_07082015.pdf here].<br />
<br />
<br />
==7/1/2015==<br />
<br />
Present: Chao, Vince, Jie, JP, Min, Melissa <br><br />
By Phone: Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Min<br />
**Gave an update on acceptance studies. She showed a summary table of each energy <br>setting and septum configuration. There hasn't been any problems in the 2.2 GeV, 5T <br>longitudinal and 1.7 GeV, 2.5T transverse settings, but some settings (2.2 GeV, 2.5T <br> transverse, 1.2 GeV, 2.5T transverse and 2.2 GeV, 5T transverse) have a discrepancy <br>in the focal plane between data and simulation. She compared the data divided by the <br>Mott XS to the simulation results without XS, and found that the simulation results <br>of &theta; and &phi; are narrower then the data. JP commented that, while including the Mott<br>XS might change the shape of the distribution, it shouldn't change the boundary. She <br>work on figuring out the cause for this discrepancy before calculating the acceptance. <br>More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07012015/07012015.pdf here].<br />
<br />
*Pengjia<br />
**Comparing asymmetries determined from the MAID model to those calculated from data.<br>Last time he showed a factor of 6 difference between the two results. He determined the <br>scattering angle and Q<sup>2</sup> by fitting the data and compared them to the quantities calculated <br>from MAID. He also showed the results of calculating the quantities g<sub>1</sub>, g<sub>2</sub>, F<sub>1</sub>, F<sub>2</sub>, A<sub>L</sub>, A<sub>T</sub>,<br> dXS<sub>L</sub>, dXS<sub>T</sub>, XS<sub>tot</sub> andXS<sub>mott</sub> using MAID. He hasn't included radiative corrections in his <br>calculations, but this probably won't account for the factor of 6. More details can be seen <br>in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07012015/MAID_20150701.pdf here].<br />
<br />
<br />
----<br />
<br />
==Jan-June 2015==<br />
[[Minutes_Jan2015_to_June2015]]<br />
----<br />
<br />
==July-Dec 2014==<br />
[[Minutes_July2014_to_Dec2014]]<br />
----<br />
<br />
==Jan-June 2014==<br />
[[Minutes_Jan2014_to_June2014]]<br />
----<br />
<br />
==June-Dec 2013==<br />
[[Minutes_June2013_to_Dec2013]]<br />
----<br />
<br />
==Jan-May 2013==<br />
[[Minutes_Jan2013_to_May2013]]<br />
----<br />
<br />
==April-Dec 2012==<br />
[[Minutes_Apr2012_to_Dec2012]]<br />
----<br />
<br />
==Jan-March 2012==<br />
[[Minutes_Jan2012_to_Mar2012]]<br />
----<br />
==July-Dec 2011==<br />
[[Minutes_July2011_to_Dec_2011]]<br />
----<br />
==Jan-June 2011==<br />
[[Minutes_Jan2011_to_June_2011]]<br />
----</div>Melissachttps://hallaweb.jlab.org/wiki/index.php?title=G2p_Weekly_Analysis&diff=26354G2p Weekly Analysis2015-11-25T14:24:46Z<p>Melissac: /* AGENDAS */</p>
<hr />
<div>Analysis meetings are held every Wednesday at 9:00 in F228. ([https://hallaweb.jlab.org/wiki/index.php/G2p_Analysis_Minutes Minutes])<br />
<br />
The conference phone number is 866-740-1260 (US) or 303-248-0285 (International). Access Code: 1466792<br />
<br />
Please edit the agenda to link to your talk prior to the start of the meeting. For help doing this, [https://hallaweb.jlab.org/wiki/index.php/Getting_Started_with_the_g2pWiki click here] <br />
<br />
Group members can post files at /u/group/halla/www/hallaweb/html/experiment/g2p/collaborators, <br><br />
which will then be accessible on the web from http://hallaweb.jlab.org/experiment/g2p/collaborators/<br />
<br />
=AGENDAS=<br />
<br />
'''Wednesday, November 25 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
|[http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/g1_g2/g1g2_11_25.pdf Very Preliminary g1,g2] <br />
|Melissa<br />
|}<br />
<br />
<br />
'''Wednesday, November 18 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
|[http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/11182015/raster_cut_library.pdf Raster cut lib] <br />
|Pengjia<br />
|-<br />
|[http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/updatedDB_acc.pdf Acceptance with updated optics DB] <br />
|Toby<br />
|}<br />
<br />
<br />
'''Wednesday, November 10 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
|[http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/g1_g2/g1g2_11_10.pdf Very Preliminary g1/g2] <br />
|Melissa<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20151111/Chao_WeeklyMeeting_11112015.pdf Optics Update] <br />
| Chao<br />
|}<br />
<br />
<br />
'''Wednesday, November 4 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_11415.pdf g2p Elastic Tail and Angle Reconstruction] <br />
|Ryan<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/yields_update_2015_11_04.pdf Yields Study] <br />
| Jie<br />
|}<br />
<br />
<br />
'''Wednesday, October 28 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Asym/Asym_10_28.pdf Systematic Uncertainties] <br />
| Melissa<br />
|}<br />
<br />
<br />
'''Wednesday, October 14 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/slifer/2015/slifer_g2pcollab_101415.pdf Overview] <br />
| Karl<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/graduate_2015.pdf graduate] <br />
| Pengjia<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/talks/MCummings_CollabMeeting_20151013.pdf update] <br />
| Melissa<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/collaborationupdate.pdf dilution update/outlook] <br />
| Toby<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_10_09_simulation/2015_10_14_collaboration_meeting.pdf Update] <br />
| Jie<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/collab/10142015_collab_Min.pdf Update] <br />
| Min<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20151014/Chao_WeeklyMeeting_10142015.pdf Update] <br />
| Chao<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_101315.pdf Update] <br />
| Ryan<br />
|}<br />
<br />
<br />
'''Wednesday, September 30 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/diltalk_093015.pdf dilution update] <br />
| Toby<br />
|}<br />
<br />
<br />
'''Wednesday, September 23 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/09222015/asym_g12.pdf asymmetry] <br />
| Pengjia<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/09232015.pdf Acceptance Spectrum] <br />
| Min<br />
|}<br />
<br />
<br />
'''Wednesday, September 16 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_09_15_simulation/2015_09_15_Simulation_update.pdf simulation update] <br />
| jie<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_091615.pdf Model Calc. of Physics Quantities] <br />
| Ryan<br />
|}<br />
<br />
<br />
'''Wednesday, September 9 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_09_09_simulation_update/2015_09_09_Simulation%20update.pdf simulation update] <br />
| jie<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150909/Chao_WeeklyMeeting_09092015.pdf Optics Update] <br />
| Chao<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/09092015/asym_20150909.pdf asymmetry] <br />
| Pengjia<br />
|}<br />
<br />
<br />
'''Wednesday, September 2 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Pion/PionAsym_08_31.pdf Pion Asymmetries] <br />
| Melissa<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_09215.pdf Model Calc. of Physics Quantities] <br />
| Ryan<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/acceptance_scatangle.pdf Scattering Angle study contd.] <br />
| Toby<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/09022015.pdf Acceptance Tuning] <br />
| Min<br />
|}<br />
<br />
<br />
'''Wednesday, August 26 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150826/Chao_WeeklyMeeting_08262015.pdf Optics Update] <br />
| Chao<br />
|}<br />
<br />
<br />
'''Wednesday, August 19 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Pion/PionAsym_08_19.pdf Pion Asymmetries] <br />
| Melissa<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/08192015.pdf Acceptance Update] <br />
| Min<br />
|}<br />
<br />
<br />
'''Wednesday, August 12 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150812/Chao_WeeklyMeeting_08122015.pdf Optics Update] <br />
| Chao<br />
|}<br />
<br />
<br />
'''Wednesday, July 29 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07272015/07292015.pdf Acceptance - Optics run] <br />
| Min<br />
|}<br />
<br />
<br />
'''Wednesday, July 22 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_07_22.pdf Epics Checks for Pf Analysis] <br />
| Melissa<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07222015/MAID_update_20150722.pdf MAID update] <br />
| Pengjia<br />
|}<br />
<br />
<br />
'''Wednesday, July 15 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150715/Chao_WeeklyMeeting_07152015.pdf Optics Update] <br />
| Chao<br />
|}<br />
<br />
<br />
'''Wednesday, July 8 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07082015/MAID_update_20150708.pdf MAID update] <br />
| Pengjia<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/scatangle_talk.pdf model reconstruction - scattering angle study] <br />
| Toby<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_07_08.pdf Summary of Pf Analysis ] <br />
| Melissa<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07082015/07062015.pdf Dp Comparison ] <br />
| Min<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150708/Chao_WeeklyMeeting_07082015.pdf Optics Update] <br />
| Chao<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_07_05_plots/2015_07_06_Simulation_update.pdf Simulation Update] <br />
| Jie<br />
|}<br />
<br />
<br />
'''Wednesday, July 1 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07012015/07012015.pdf Acceptance Update] <br />
| Min<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07012015/MAID_20150701.pdf MAID asymmetry] <br />
| Pengjia<br />
|}<br />
<br />
<br />
'''Wednesday, June 24 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Technotes/PF_technote_draft.pdf PF Technote Draft] <br />
| Melissa<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/asymplots.pdf Asymmetry plots] <br />
| Toby<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_06_24_simulation/2015_06_25_Simulation_update.pdf simulation update] <br />
| Jie<br />
<br />
|}<br />
<br />
<br />
'''Wednesday, June 17 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_061715.pdf Pol Rad Corrections] <br />
| Ryan<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/anglecorrection.pdf Angle Correction to simulation] <br />
| Toby<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/06172015/06172015.pdf Acceptance Study - Dilution] <br />
| Min<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/Chao_WeeklyMeeting_06172015.pdf Optics Update] <br />
| Chao<br />
|}<br />
<br />
<br />
'''Wednesday, June 10 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_06_09_simulation/2015_06_10_Simulation_update.pdf Simulation update] <br />
| Jie<br />
|}<br />
<br />
<br />
'''Wednesday, May 27 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/05272015/maid_asym_20150527.pdf Asymmetries from MAID] <br />
| Pengjia<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/05272015/05272015.pdf Acceptance Update 3rd septum] <br />
| Min<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/05272015/Chao_WeeklyMeeting_05272015.pdf Optics Update] <br />
| Chao<br />
|}<br />
<br />
<br />
'''Wednesday, May 20 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/05202015/maid_asym.pdf Asymmetries from MAID] <br />
| Pengjia<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_05_20_snakefield/2015_05_20_hrsfield_update.pdf q1 and septum field] <br />
| Jie<br />
<br />
|}<br />
<br />
<br />
'''Wednesday, May 13 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_05_13_simu_rad_technotes/radiation_simulation_technotes.pdf energy-loss technotes] <br />
| Jie<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/dilutionnote.pdf dilution note] <br />
| Toby<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_05_13.pdf 1.1 GeV Elastic Yields] <br />
| Melissa<br />
|}<br />
<br />
<br />
'''Wednesday, May 6 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150506/Chao_WeeklyMeeting_05062015.pdf Optics Update] <br />
| Chao<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/05062015/05062015.pdf Acceptance Update] <br />
| Min<br />
|}<br />
<br />
<br />
'''Wednesday, April 29 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/04282015/Asymmetries%20for%20different%20raster%20cut.pdf Asymmetries for different raster cut] <br />
| Pengjia<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_04_29.pdf Pf Update] <br />
| Melissa<br />
|}<br />
<br />
<br />
'''Wednesday, April 22 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/technotes/bcm_technote.pdf BCM technote draft] <br />
| Pengjia<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/qualitychecktalk.pdf Quality check summary] <br />
| Toby<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150422/Chao_WeeklyMeeting_04222015.pdf Optics Update] <br />
| Chao<br />
|}<br />
<br />
<br />
'''Wednesday, April 15 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_04_15_acc/2015_04_15_Simulation_update.pdf SIMULATION Update] <br />
| Jie<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_04_15.pdf Pf Update] <br />
| Melissa<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_041515.pdf Rad Corrections] <br />
| Ryan<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/diltalk_041515.pdf Dilution Update] <br />
| Toby<br />
|}<br />
<br />
<br />
'''Wednesday, April 8 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150408/Chao_WeeklyMeeting_04082015.pdf Optics Update] <br />
| Chao<br />
|}<br />
<br />
<br />
'''Wednesday, April 1 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_04_01.pdf PF Update] <br />
| Melissa<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_040115.pdf Model Tune] <br />
| Ryan<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/04012015/04012015.pdf Acceptance Update] <br />
| Min<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_03_31_bpmpos/2015_03_31_Simulation_update.pdf Simulation Update] <br />
| Jie<br />
|}<br />
<br />
<br />
'''Wednesday, March 25 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_03_23_rad_effects/2015_03_25_Simulation_updae.pdf Simulation_update] <br />
| Jie<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/pf_dil_talk.pdf Dilution update] <br />
| Toby<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150325/Chao_WeeklyMeeting_03252015.pdf Optics Update] <br />
| Chao<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/03252015/asym_lr.pdf asymmetry] <br />
| Pengjia<br />
|}<br />
<br />
<br />
'''Wednesday, March 18 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_03_18.pdf Packing Fraction] <br />
| Melissa<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_031715.pdf Model Tune] <br />
| Ryan<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/03182015/03182015.pdf Acceptance Update] <br />
| Min<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/03112015/ Rastercut update] <br />
| Pengjia<br />
|}<br />
<br />
<br />
'''Wednesday, March 11 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_03_06_xs_ratio/2015_03_11_Simulation_updae.pdf simulation update] <br />
| Jie<br />
|}<br />
<br />
<br />
'''Wednesday, March 4 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/diltalk_030415.pdf dilution analysis] <br />
| Toby<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_030415.pdf Model Tune] <br />
| Ryan<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_03_04.pdf Packing Fraction] <br />
| Melissa<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/03042015/03042015.pdf Acceptance Update] <br />
| Min<br />
|}<br />
<br />
<br />
'''Wednesday, February 25 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_02_24_yields/Simulation_update_2015_02_24.pdf yields study] <br />
| Jie<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/technotes/Chao_TechNote_TargetField.pdf TN: Target Field Mapping TN Draft] <br />
| Chao<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/02252015/Position_Cut_20150225.pdf position cut for yields study] <br />
| Pengjia<br />
|}<br />
<br />
<br />
'''Wednesday, February 18 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/02182015/librastercut.pdf rastercut library(not available)] <br />
| Pengjia<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/02182015/02182015.pdf Acceptance Update] <br />
| Min<br />
|}<br />
<br />
<br />
'''Wednesday, February 11 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/dilution021015.pdf Dilution update] <br />
| Toby<br />
|}<br />
<br />
<br />
'''Wednesday, February 4 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Yields/Yields_02_03.pdf Run Quality Check - RHRS] <br />
| Melissa<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150204/Chao_WeeklyMeeting_02042015.pdf RHRS Optics Update] <br />
| Chao<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_02_04_radiative/2015_02_04_Simulation_updae.pdf Simulation update] <br />
| Jie<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/02042015/02042015.pdf Acceptance Update] <br />
| Min<br />
|}<br />
<br />
<br />
'''Wednesday, January 28 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_012815.pdf 1.157 GeV Run Quality Check] <br />
| Ryan<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/01282015/yield_drift_20150128.pdf run quality check] <br />
| Pengjia<br />
|}<br />
<br />
<br />
'''Wednesday, January 21 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Yields/Yields_01_21.pdf Data Quality Check for 2.2GeV, 2.5T] <br />
| Melissa<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150121/Chao_WeeklyMeeting_01212015.pdf RHRS Optics Update] <br />
| Chao<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/01212015/01212015.pdf Acceptance Update] <br />
| Min<br />
|}<br />
<br />
<br />
'''Wednesday, January 14 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/scaler_yield_drift_talk.pdf Yield Drift Study - Scalers] <br />
| Toby<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_011415.pdf 1.157 GeV Run Quality Check] <br />
| Ryan<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_01_12_dp/Simulation_update_2015_01_12.pdf dp] <br />
| Jie<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/01152015/data_quality_20150115.pdf 1.711 GeV run quality check] <br />
| Pengjia<br />
|}<br />
<br />
<br />
'''Wednesday, January 7 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/talks/MCummingsCollabMeeting_Jan.pdf Analysis Updates] <br />
| Melissa<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150107/Chao_WeeklyMeeting_01072015.pdf Optics Update] <br />
| Chao<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/CollabMeeting_12015.pdf Analysis Update] <br />
| Ryan<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/01072015/01072015.pdf Acceptance Update] <br />
| Min<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_01_06_pbosted/2015_01_06_Simulation_update.pdf simulation Update] <br />
| Jie<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/01.07.15.pdf dilution/quality check update] <br />
| Toby<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/01072015/false_asym_20150107.pdf false asymmetry] <br />
| Pengjia<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/slifer/2015/slifer_g2pcollab_010715.pdf Review]<br />
| Karl<br />
|}<br />
<br />
<br />
<br />
==2014==<br />
[[Slides_2014]]<br />
<br />
==2013==<br />
[[Slides_2013]]<br />
<br />
==2012==<br />
[[Slides_2012]]<br />
<br />
==2011==<br />
[[Slides_2011]]</div>Melissachttps://hallaweb.jlab.org/wiki/index.php?title=G2p_Analysis_Minutes&diff=26338G2p Analysis Minutes2015-11-19T15:07:48Z<p>Melissac: /* 11/11/2015 */</p>
<hr />
<div>Minutes of the weekly analysis meetings<br />
----<br />
[https://hallaweb.jlab.org/wiki/index.php/G2p_Weekly_Analysis Agenda]<br />
<br />
==11/18/2015==<br />
<br />
<br />
Present: Min, JP, Melissa <br><br />
By Phone: Vince, Jie, Toby, Ryan, Karl, Ellie, Chao <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Toby<br />
**Gave an update on using the newest optics reconstruction matrix. He showed an example of one<br>run, located way past the delta resonance, so the dp distribution should be fairly flat. He tried <br>applying the phi cuts he has shown previously to remove acceptance and scattering angle effects,<br> but making a cut on phi revealed a strange structure in the dp spectrum. He showed the phi vs. dp <br>reconstruction both at the septum plane (i.e. without target effects) and after being reconstructed <br>back to the target. The strange structure exists in both distributions, so it is probably not a target <br>field effect. He is currently working with Chao to resolve this; Chao is doing a comparison of the <br>old and new databases to determine which element is causing this effect. More details can be seen <br>in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/updatedDB_acc.pdf here].<br />
**He has updated the target polarization uncertainties in the mysql. He will send out an email to the <br>collaboration with more details about this.<br />
<br />
*Pengjia<br />
**Showed the results of a study to check the effect of applying raster cuts on the yield. He showed <br>several examples of groups of runs where the yield was drifting. In some cases, the raster cuts <br>got rid of the drift in the yields, or at least made the drift significantly smaller. For one setting, the <br>raster cut did not resolve the change in yields, so there is likely something else causing the drift. <br>JP suggested doing some sanity check to confirm that the method works, such as starting with <br>a setting that has consistent yields and applying the raster cuts to see the effect. More details <br>can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/11182015/raster_cut_library.pdf here].<br />
<br />
<br />
==11/11/2015==<br />
<br />
Present: JP, Melissa <br><br />
By Phone: Vince, Toby, Ryan, Chao, Min, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Showed "very preliminary" results for g1/g2. She is using a dilution factor determined from <br>the Bosted model, and using the average value of the packing fraction for each material. For the <br>radiative corrections, she is using a model prediction for the asymmetry where the polarized piece <br>comes from the MAID model and the unpolarized cross section is the Bosted model. The difference <br>between the model prediction ''without'' radiative effects and the model prediction ''with'' radiative effects <br>is used as an additive correction to the asymmetry. There was some concern over the large effect <br>of the R.C. at high W. Ryan commented that the final R.C will be large, so they will need to be done<br>very carefully. A cross check with EG1 data will be helpful. In order to match the kinematics of the<br>longitudinal and transverse settings, she scaled the asymmetry by the ratio of the unpolarized cross<br>section at the two different kinematic settings. JP commented that this is not valid, and suggested <br>using model input for the asymmetries, instead of trying to match the kinematics between the data<br>taken in the longitudinal and transverse settings. Next she will work on updating systematics for the <br>asymmetries and structure functions. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/g1_g2/g1g2_11_10.pdf here].<br />
<br />
*Chao<br />
**Gave an update on optics analysis. Comparisons of the data with simulation revealed that there <br>were offsets in the reconstructed kinematics. This correction could be fixed using a finely-tuned<br>fitting procedure. The longitudinal setting has already been fixed, today he showed the results <br>for the 1.7 GeV, transverse setting. He showed the results of doing the calibration; most of the <br>holes near the center have a difference of less than 0.5 MeV between data and simulation. He is <br>currently working on finishing the other transverse settings. More details can be found in his <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20151111/Chao_WeeklyMeeting_11112015.pdf here].<br />
<br />
==11/4/2015==<br />
<br />
Present: Min, Jixie, Melissa <br><br />
By Phone: Chao, Vince, Toby, Ryan, Alex, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Ryan<br />
**Gave an overview of g2p elastic tail and angle reconstruction. The elastic tail is highly sensitive<br>to the scattering angle, so his goal is to develop a method to include these variations in the elastic <br>tail subtraction. He started by looking at the simplest case, helium dilution runs. Using his method, <br>he looked at the elastic tail across a series of different momentum settings, andfound that the tail <br>was not continuous, which he assumed was due to variations in the scattering angle. He did a pseudo-<br>simulation using the Bosted model and varying the scattering angle to confirm the "jump" seen in the <br>elastic tail. However, when he looked at the normalized yields for this same data, he did not see the <br>same discontinuity. This suggests there might be a problem with the scattering angle reconstruction. <br>Chao mentioned that the reconstruction code has been updated (at least for the longitudinal setting) <br>the last replay; he will provide this code to Toby so he can do another replay. Details of the method <br>and cuts used can be seen in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_11415.pdf here].<br />
<br />
*Jie<br />
**Gave an update on his simulation study to understand the beam dependence on the yields. He used the <br>beam position and raster size as input to g2psim, and included radiative and acceptance effects. In <br>general, he found there is a much larger dependence on the beam position using a rastered beam <br>compared to a point beam. He summarized his results for various different momentum settings and found <br>that, in some cases, his results matched what we saw in the data, but not in all cases. Vince suggested <br>testing how much the beam position would need to be changed (for a given momentum setting) to match <br>the simulation with the data. The details of his study can be found in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/yields_update_2015_11_04.pdf here], he is also compiling <br>a technote on this analysis.<br />
<br />
==10/28/2015==<br />
<br />
Present: JP, Min, Kalyan, Melissa <br><br />
By Phone: Alexandre, Vince, Jie, Ryan, Toby, Ellie, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Gave an overview of contributions to the systematic uncertainty for the asymmetry. There are <br>several contributions which are very small (<0.1%) including the charge asymmetry, livetime <br>asymmetry and pion contamination. The target polarization uncertainty was surprisingly small.<br>The values currently listed in the mysql DB for this quantity appear to be incorrect; Toby will<br>update these values. For the contribution from the dilution factor and radiative corrections, she<br> assigned 5% as a placeholder until a better estimate could be made. Karl/Ryan commented <br>that 5% uncertainty on the radiative corrections may be too small, 10-15% would be a better<br>estimate at this point. The tables shown for the longitudinal and transverse settings represent<br>an overestimate of the uncertainty; in the long-term this could be looked at more carefully to<br>decrease the overall systematic uncertainty. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Asym/Asym_10_28.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*There has been a request from the Hall A CC to have an update on g2p at the winter collaboration <br>meeting. Ellie and Jie are both interested, they will check the dates of the meetings to see if they <br>are available.<br />
<br />
==10/14/2015==<br />
<br />
Present: JP, Min, Jixie, Kalyan, Melissa <br><br />
By Phone: Alexandre, Vince, Jie, Todd, Haiyan, Pengjia, Karl, Toby, Ryan, Xiaochao, Nilanga, Chao <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Karl<br />
**Went over the goals of the collaboration meeting:<br />
***Discuss physics topics for students graduating soon<br />
***Identify major remaining physics topics<br />
***Establish a policy for the release of plots<br />
**Suggested a policy for collaboration release of physics results, including specific requirements <br>for moving from "very preliminary" to "preliminary" to "final" results. Details can be seen in his <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/slifer/2015/slifer_g2pcollab_101415.pdf here], and they will be circulated to the g2p mailing list with some small modifications.<br />
<br />
*Pengjia<br />
**Will be defending next Wednesday (Oct. 21st). He showed a "very preliminary" physics <br> asymmetry for the 2.2 GeV 5T setting (both longitudinal and transverse) with a comparison to <br> a radiated model prediction. He used this result to extract a preliminary value for g1 and g2,<br>using the Bosted model as input for the cross section. This result does not include radiative<br>corrections. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/graduate_2015.pdf here].<br />
<br />
*Min<br />
**Showed an overview of status of acceptance study; the overall goal is to match the simulation<br>results to the data, so that the simulation can be used to calculate the acceptance. She<br>described the various attempts to correct the simulation results to match the data. Adjusting the<br> apertures based on optics data works well, but the other two methods (adjusting the apertures <br>based on dilution data and adjusting the acceptance cuts after removing the Mott XS from the <br>data) only work well around the target run. In addition, the simulated yield has a different shape <br>than the data, so the simulation must be adjusted to match this. She will go through this process <br>again once Chao is finished with the optics correction. She is planning to graduate next January, <br>and would like to include a cross section difference for one kinematic setting in her thesis. More <br>details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/collab/10142015_collab_Min.pdf here].<br />
<br />
*Melissa<br />
**Gave an overview of packing fraction analysis. Of the 5 total settings there are 3 that are reasonably <br>stable with some small drifts in yields, and 2 settings that have larger problems. During the 2.2 GeV, <br>2.5T setting the raster size was changed, which could possibly be corrected by applying a cut on<br>the center of the raster. The 1.1 GeV setting has large variations in the elastic yields; some of these <br>runs were taken at low currents (8-20nA), so the beam position information is not reliable. She also <br>showed the results of a pion asymmetry study. Although the pion asymmetry is very large, the <br>residual pion contamination after PID cuts are applied is very small, so the correction is not large. <br>She has scheduled her defense for December 4th, and would like to include a preliminary result <br>for g1,g2 in her thesis. To include a fully corrected result she will need preliminary radiative <br>corrections and dilution results, which she will work with Ryan and Toby to get. More details can <br>be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/talks/MCummings_CollabMeeting_20151013.pdf here].<br />
<br />
*Toby<br />
**Showed a preliminary dilution value that he had shown previously, and described several issues <br>with the result. These issues include that the model assumes a constant scattering angle, and does <br>not include some acceptance effects that are seen in the data. He has been working on correcting <br>these issues by incorporating a scattering angle from data into the model and applying acceptance <br>cuts to the data to remove acceptance effects. He showed the result of applying the acceptance cut <br>across all kinematics for the 5T longitudinal setting; including the acceptance cut gets rid of some of <br>the strange structure seen in the yields, such as the sawtooth pattern seen at high nu. The downside <br>of this method is that the acceptance cut causes a large loss in statistics. He is currently working on <br>trying to re-incorporate some of the lost statistics from the acceptance cut. More details can be seen <br>in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/collaborationupdate.pdf here].<br />
<br />
*Jie<br />
**Gave an update on his study using simulation to understand the drifts in yields. He looked at several <br>momentum settings in the 2.2 GeV, 2.5T setting that had variation in the yields. He varied the beam <br>position along the horizontal and vertical directions using both a point beam and rastered beam. He <br>generated a table summarizing the results using a Monte Carlo method, cross checking with averaged <br>acceptance. His results were similar to his previous test using only the Bosted model; some results <br>agree with what was seen in the data, some have the opposite sign. He will write up his method and <br>results in a technote. He is planning to graduate in summer of 2016. More details can be seen in his <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_10_09_simulation/2015_10_14_collaboration_meeting.pdf here].<br />
<br />
*Chao<br />
**Gave an update on optics analysis. Comparisons of simulation with data revealed that the <br>reconstructed kinematics have some offset. A correction was added to the reconstructed kinematics <br>(vs beam position) and he is currently working on merging this correction into the database with a <br>finely tuned fitting procedure. The problem is that the horizontal beam position shifts the dp <br>reconstruction. He showed the results of applying the new optics matrix which corrects for this shift. <br> He will apply this method to all kinematic settings and study the uncertainty of the optics. Once this <br>is done he will write a NIM paper for g2p optics. He plans to graduate in February/March and would <br>like to include the cross section difference for one or two settings with tuned acceptance and model <br>inputs to obtain a physics result. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20151014/Chao_WeeklyMeeting_10142015.pdf here].<br />
<br />
*Ryan<br />
**Since the last collaboration meeting he has improved the model tuning procedure by using an <br>automated procedure instead of tuning the model by hand. He has tested this using carbon data <br>from the UVa database and will run it for nitrogen data once he has updated saGDH N2 cross <br>sections from Vince. He also updated the systematic error study for inelastic unpolarized radiative <br>corrections by separating the integration/iteration error from the interpolation error. He has the <br>polarized radiative correction code running, and has completed a systematic uncertainty study on <br>the inelastic radiative corrections. He is also working on evaluating physics quantities using models, <br>specifically the hyperfine splitting calculation. He plans to graduate in summer/fall of 2016 and would <br>like to include full radiative corrections on g2p polarized cross sections in his thesis. More details can<br> be seen in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_101315.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*Important to do cross checks of results between students (ex. asymmetries)<br />
*Must be careful to include details of any physics results (whether radiative corrections are included,<br>dilution factor, model input instead of data, etc.)<br />
<br />
==9/30/2015==<br />
<br />
Present: JP, Kalyan, Jixie, Min <br><br />
By Phone: Pengjia, Toby, Ryan, Vince, Jie, Chao, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Toby<br />
**Showed an update on his acceptance/dilution study. He continued with the study of the cuts on the <br>reconstructed &theta; vs &phi; distribution at the target. He scanned several different &theta; vs &phi; cuts to see how <br>the acceptance effects the scattering angle and resulting yields. It turns out the small angle region is <br>influenced by the acceptance a lot but the center region gives a good agreement to the model. He <br>also loosed the center cut to &theta; ~ ± 40 mrad and &phi; ~ ± 10 mrad, the data still agreed with the model. <br>He then recalculated the dilution factor for 2.254 GeV longitudinal setting. More details on his <br>acceptance cuts and method can be found in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/diltalk_093015.pdf here].<br />
<br />
<br />
==9/23/2015==<br />
<br />
Present: JP, Kalyan, Min, Melissa <br><br />
By Phone: Pengjia, Toby, Ryan, Vince, Jie, Chao, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Pengjia<br />
**Showed the structure of his code to create a radiated model of the MAID and Bosted <br>models, based on Ryan's radiative correction work. He showed the breakdown of the <br>different components to the radiated model (internal, external and elastic tail). He used<br> the radiated model to calculate an asymmetry and cross section differences, which he <br> compared with data. Finally, he combined asymmetries calculated from data with the <br>Bosted model cross section to calculate a value for g1 and g2, which he compared <br>with values of g1/g2 determined using the MAID model. More details can be seen in <br>his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/09222015/asym_g12.pdf here].<br />
<br />
*Min<br />
**Gave an update on acceptance studies. Last time, she found that by adjusting the<br>apertures in the simulation she could match the data/simulation results for dp (for one <br>momentum setting). She tested this method for other momentum settings and found <br>that it did not work as well. She also showed a comparison of the yield spectrum for<br>helium runs in the 1.7 GeV setting; the shape of the two distributions are quite <br>different, which might suggest that the model deviates significantly form the data. In<br>the simulated results she saw several "bumps" in the yield, which correspond to the<br>location of resonances. She will update these results when the optics corrections are <br>complete. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/09232015.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*We would like to schedule another collaboration meeting in the near future. The <br>meeting is tentatively scheduled for Wednesday October 14th during our usual meeting <br>time (10am-12pm).<br />
*The purpose of the meeting is to:<br />
**Discuss student thesis topics (particularly any updates from the last <br>collaboration meeting)<br />
**Establish a procedure for presentation/release of collaboration plots/results<br />
*Each student should prepare a few slides (~5 minutes) to show analysis progress<br />
<br />
<br />
==9/16/2015==<br />
<br />
Present: Min, JP, Jixie, Melissa <br><br />
By Phone: Vince, Jie, Chao, Pengjia, Alex, Ryan, Toby, Ellie <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Jie<br />
**Gave an update on his simulation study using MUDIFI. Last time he showed that he uses a<br>least square fit to go from endplane to endplane. For the g2p simulation, it's used to go from<br>(x,y,&theta;,&phi;,dp) in the target plane to (x,y,&theta;,&phi;,dp) in the focal plane. SNAKE produces (x,y,&theta;,&phi;,dp)<br>data in both planes and a polynomial function can be used to determine the relationship<br>between the two planes. First the maximum power for each variable is determined, symmetries<br>are included (if applicable), then the priority of each function must be determined. A Gram-<br>Schmidt transformation is used to do the minimization, and the final step is to decide whether<br>to accept the function f<sub>i</sub>. JP/Vince asked how the priority for each function is chosen, since the<br>choice could introduce some ordering dependence. Since we don't have enough data to<br>constrain, JP suggested introducing some physics. He also suggested getting rid of dp in the<br>focal plane (since it is really just dp in the target plane) so that there is one less dimension to<br>fit. More details can be seen in Jie's slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_09_15_simulation/2015_09_15_Simulation_update.pdf here].<br />
<br />
*Ryan<br />
**Gave an update on evaluating physics quantities using models. His goal was to do a<br>comparison of the hyperfine splitting calculation in C. Carlson's 2006/2008 paper using MAID<br>and Hall B models. Previously he showed a comparison using the Hall B model, where he saw<br>good agreement between his calculation and Carlson's result. For this time he also did a<br>comparison using the MAID model. There is a large difference between the two models for the<br>value of the integrand of &Delta;<sub>2</sub>, over the full range of Q<sup>2</sup>. JP suggested comparing the value of g2<br>between the two models, instead of &Delta;<sub>2</sub>. More details can be seen in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_091615.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*Toby<br />
**Last time he showed a comparison between data and cross sections calculated using the<br>Bosted model (seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/acceptance_scatangle.pdf here]). The model was not continuous for one momentum setting. It <br>turns out the BPM was not recording for that setting, so he re-calculated the XS using<br>values for &theta; and &phi; from surrounding runs and found that the result was now consistent with<br>the neighboring momentum settings. He also played around with the acceptance cuts he<br>showed, and found a region using the "extreme cut" where the sawtooth pattern go away<br>and the yields become flat.<br />
<br />
<br />
==9/9/2015==<br />
<br />
Present: Min, JP, Jixie, Melissa <br><br />
By Phone: Vince, Jie, Chao, Ryan, Toby, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Jie<br />
**Gave an overview of his simulation study using SNAKE and MUDIFI. Using SNAKE, the<br>idea is to trace the particle trajectory in a series of free boxes, then an endplane can be<br>defined within the free boxes to determine the trajectory from endplane to endplane. In<br>g2psim this will be used to trace the trajectory between the sieve plane and the focal<br>plane. There are two important issues to consider, the magnetic field in the free boxes,<br>and the transportation method between the two endplanes. A Runge-Kutta method is <br>used for the transportation, and an adaptive method (which changes with field size and<br>gradient) is used to determine the step size. For the magnetic field, a 3D Tosca field<br>map is used for the septum, and an analytic model is used for the spectrometer magnets. <br> He also described the method for choosing the transportation function to determine the <br>25 matrix terms for each kinematic variable (up to 4th order). JP asked how to determine <br>which order is more important, and cautioned to be careful not to over fit the data. He and<br>Jie will discuss this more offline. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_09_09_simulation_update/2015_09_09_Simulation%20update.pdf here].<br />
<br />
*Chao<br />
**Gave an optics status update. The current problem is that changes in the horizontal beam<br>position changes the dp reconstruction. This was fixed by applying a linear correction in<br>BPM-x and BPM-y to &theta;, &phi; and dp. Applying this correction made the data/simulation <br>agree, but it is still necessary to understand the correction. Using dp scan data with beam<br>position scan data still leaves an offset in &theta; and &phi;. He also tried two other methods to do<br>the calibration. Method 1 uses the central hole to determine a constant offset, uses the<br>horizontal beam position scan data to determine all the matrix elements related to y, and<br>uses dp scan runs to fit the additional matrix elements. Method 2 uses beam position<br>scan data to determine the matrix elements that are not related to x<sub>fp</sub>. Neither of these<br>methods works very well, even when the fitting order of the matrix elements are adjusted.<br>He will continue to check more fitting procedures. More details can be found in his slides <br>[http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150909/Chao_WeeklyMeeting_09092015.pdf here].<br />
<br />
*Pengjia<br />
**Gave an update on comparing asymmetries from data/models for the 2.2 GeV, 5T <br>longitudinal setting. He first radiated the Bosted model XS; he showed the break down of<br>the different radiative corrections including the elastic tail (internal and external) and the<br>radiative effects from inelastic scattering. He showed a comparison with Ryan's results<br>which had good agreement, though there is some deviation when he used different proton<br>form factors (provided by Moshe). In order to compare the asymmetry result with data, he<br>needs to do the radiative corrections for the polarized MAID model, which he will continue<br>to work on. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/09092015/asym_20150909.pdf here].<br />
<br />
<br />
==9/2/2015==<br />
<br />
Present: JP, Min, Kalyan, Melissa <br><br />
By Phone: Vince, Alex, Jie, Chao, Ryan, Toby, Ellie, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Gave an update on determining the correction to asymmetries for pion contamination. <br>Previously, she used the 2.2 GeV, 5T longitudinal setting as an example, for this time <br>she used the transverse configuration, as it has the largest pion contamination. She <br>modified her method for differentiating between electrons and pions; previously she <br>identified pions as events that do not trigger the Cherenkov, this time she used a cut <br>below the single photo electron peak to select pions. JP suggested using stricter cuts <br>for selecting pions when determining the pion asymmetry, to make sure it is a clean <br>sample. Although this setting has a large pion contamination, the number of pion<br> events that remain after lead glass cuts are applied is low, so the overall correction <br>is very small. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Pion/PionAsym_08_31.pdf here].<br />
<br />
*Min<br />
**Gave an update on acceptance tuning. She looked at results from the 1.7 GeV setting <br>and found that the height of the peaks is different between data and simulation for <br>different holes in the sieve slit. Looking at the &theta; vs &phi; distribution, she noticed on the<br>positive &theta; side there were fewer holes in simulation than in data, and on the negative <br> &theta; side there were more holes in simulation compared to data. She tried adjusting the<br>aperture cuts by changing the physical location of the Q1, Q2 and septum planes to <br>uncover events that were previously blocked. After the adjustment, the data/simulation <br>results agreed much better. She showed a similar procedure for a dilution run and was<br>able to see better agreement between data/simulation after the aperture adjustments <br>were made. JP/Vince suggested being cautious when adjusting the aperture cuts, as<br> the apertures should be well defined already. They suggested adjusting things that are<br> less well known first, such as the septum field. More details can be seen in her slides<br>[http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/09022015.pdf here].<br />
<br />
*Ryan<br />
**Working on generating physics quantities using models to eventually compare with data.<br>So far, he has incorporated the MAID2007 and Hall B models. He calculated the <br>hyperfine splitting quantities &Delta;1 and &Delta;2 using the Hall B EG1 model and compared them<br> to the results in C. Carlson's 2006 paper. His results agreed very well, he only saw a<br> small deviation for &Delta;2 in the lowest Q<sup>2</sup> range. To check that nothing strange was going <br> on in the low Q<sup>2</sup> range, he calculated &Delta;2 for various small ranges around zero, to ensure<br>that the integration method is well behaved. The Carlson paper also includes calculations <br>using the Simula model, he would like to do a check of this method as well, but is unsure <br>where to find the Simula model. Since he was able to reproduce the hyperfine splitting <br>result, he is confident in his calculation method; it should be straightforward to calculate <br>other spin structure function integrals. More details on his method can be found in his <br>slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_09215.pdf here].<br />
<br />
*Toby<br />
**Showed an update on his acceptance/scattering angle study. He applied cuts of varying<br>strictness on the reconstructed &theta; vs &phi; distribution at the target. He then calculated the <br>real scattering angle before/after scattering for each cut. Using these scattering angles <br> as inputs for the Bosted model he was able to calculate the XS and compare it to data.<br>He showed the comparison between data/Bosted model for each acceptance cut. He <br>hoped that the more extreme acceptance cuts on the data would flatten the yield <br>distribution, but it actually just enhanced the sawtooth pattern. JP questioned why the <br>Bosted prediction for one momentum bin (the green one) was so much lower than the<br> neighboring ones. Toby said the only input that goes into the model is the scattering angle,<br> so it must be considerably different for this momentum setting. He also commented that<br>the model prediction is scaled to match the data, so the scaling enhances the jump in<br>the model. More details on his acceptance cuts and method can be found in his slides<br>[http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/acceptance_scatangle.pdf here].<br />
<br />
<br />
==8/26/2015==<br />
<br />
Present: Jixie, Alex, Min, Kalyan, JP, Chao, Melissa <br><br />
By Phone: Vince, Jie, Ryan, Toby, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Chao<br />
**Gave an update on optics studies. Previously, he showed a comparison between optics data <br>and simulation where he cut on individual sieve holes. For this week, he included a cut on y <br>and dp that he didn't include previously. In the plot of &theta; vs y, JP pointed out that there were <br>additional tails on some sieve holes, Chao says these tails go away when the &phi; cut is <br>included. He showed a 2D plot of &theta; vs &phi;, along with the 1D projection of these variables. JP<br>commented that the data is more smeared out than the simulation, so it is difficult to compare <br>data with simulation results. It's possible that some of the smearing comes from events that <br>punch through the sieve slit and are not being cut out (the simulation currently assumes these <br>events are stopped by the sieve). Looking at the center hole, the data/simulation agree <br>reasonably well, but the agreement gets worse for holes on the edge of the sieve slit. Chao<br>will continue to look into this. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150826/Chao_WeeklyMeeting_08262015.pdf here].<br />
**He also mentioned that ~1 month ago he reported a problem with the [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150708/Chao_WeeklyMeeting_07082015.pdf BPM simulation].<br>He found it was actually a problem with the simulation itself, which has now been updated <br> to correct the problem.<br />
<br />
<br />
'''General Discussion:'''<br />
*Pengjia has submitted his BPM NIM paper.<br />
<br />
<br />
==8/19/2015==<br />
<br />
Present: Chao, Jie, Min, Jixie, Kalyan, Melissa <br><br />
By Phone: Vince, Ryan, Toby, Karl, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Showed a method for determining the correction to asymmetries for pion contamination. The <br>measured asymmetry can be written in terms of the electron and pion asymmetries, multiplied <br>by the fraction of events of that particle. To differentiate between electrons and pions, a cut is<br>made on events that trigger the Cherenkov detector (electrons) and events that do not trigger<br>the Cherenkov (pions). Kalyan commented that this method of selecting pions may be too blind,<br> and suggested making a 2D cut on E/p vs Cherenkov instead. To determine the fraction of<br>electrons/pions, "good event" cuts are applied (loose acceptance cuts, single track events and<br>pion rejector cuts) and the number of electrons/pions that survive the cuts are counted. Although<br>the pion asymmetry is much larger than the electron asymmetry, the number of residual pions<br>is very small, so the overall correction is small. For this example the 2.2 GeV, 5T longitudinal<br>setting was used, but the correction may be larger for the 5T transverse settings, which she <br>will do next. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Pion/PionAsym_08_19.pdf here].<br />
<br />
*Min <br />
**Gave an update on acceptance studies. She used the 1.7 GeV, 2.5T setting (with 3rd septum <br>configuration) to test the acceptance cuts using the yield ratio of data to simulation. She <br>showed a plot of target &theta; vs &phi; for both data and simulation, and applied a graphical cut to get<br>rid of events on the edges. Looking at the resulting 1D plots shows reasonable agreement<br>between &theta; and &phi;. Vince pointed out that there seems to be some additional structure in the<br>dp distribution, and suggested expanding the &delta; cut out to &pm; 4% to see if there is more <br>hidden structure. Min said she has seen this in other settings as well and will look into it. She<br>also tried adjusting the cuts on &theta;, &phi; and &delta; and looked at how the ratio of yields from data/<br>simulation changed; the ratio starts to drop off as the cuts get wider. Next she will work on<br>calculating the yields using W bins. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/08192015.pdf here].<br />
<br />
<br />
==8/12/2015==<br />
<br />
Present: Jie, Chao, Kalyan, Min, Jixie, Melissa <br><br />
By Phone: Pengjia, Ryan, Toby, Karl, Ellie, Alex <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Chao<br />
**Gave an update on optics studies. Previously, Min has shown comparisons of data/simulation<br> where she looked at different columns of sieve holes. Chao continued this study by cutting on <br>individual sieve holes. Looking at the center sieve hole, the &phi; distribution looks reasonable, but <br>the &theta; distribution has some issues. Specifically, the data is wider on the left side (negative &theta;) <br>than the simulation. He showed results for several sieve holes, including one that was in the <br>row as the center hole, but in the farthest column on the left side of the sieve slit. In this case <br>the &theta; distribution had similar width for both data and simulation, but the height of the simulation<br> distribution was larger. This may suggest that something is wrong with the acceptance in the <br>simulation. The problem with &theta; seems to be systematic; for most of the sieve holes there are <br>more events on the left side of the data than in the simulation. Kalyan asked whether the <br>thickness of the sieve slit was taken into account, Chao says it was included in the simulation <br>and optimizer. Jixie suggested comparing the dp distributions for each sieve hole. More details <br>can be seen in Chao's slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150812/Chao_WeeklyMeeting_08122015.pdf here].<br />
<br />
<br />
==7/29/2015==<br />
<br />
Present: Chao, Min, JP, Melissa <br><br />
By Phone: Alex, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Min<br />
**Gave an update on acceptance studies. Previously, Chao showed a correction for the beam<br>position in g2psim. Min checked this correction by looking at optics runs. On the data she <br>applied a cut on dp (to select elastic events) and on the focal plane (to get rid of junk <br> events). On the simulation, only an aperture cut was applied. She compared the data and<br>simulation results for &theta; and &phi; both before and after drifting from the sieve slit to the target.<br>The effect of the target field on &theta; is not very large, though there is a shift down in angle.<br>However, the shape of the &theta; distribution is different between data and simulation. The<br>effect of the target field on &phi; is significant; it's not clear why this is the case. To try to<br>determine the reason for the discrepancies, she applied a cut along each column of sieve<br>slit holes in &phi; and compared the data and simulation results for &theta;,&phi; and dp. Column 2<br>seems to have the best agreement (for dp), columns 1 and 2 have a shift while columns<br>3-6 have a difference in width. Chao suggested also cutting along each row of sieve slit<br>holes to better study the effect of the drift on &phi;. Min will work on identifying the differences<br>between data and simulation, specifically whether the boundaries are different between<br>the two. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07272015/07292015.pdf here].<br />
<br />
<br />
==7/22/2015==<br />
<br />
Present: JP, Min, Jixie, Melissa <br><br />
By Phone: Alex, Ryan, Toby, Ellie, Karl, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Showed various checks for packing fraction runs that have large discrepancies, including <br>beam position, beam energy, spectrometer central momentum setting, septum current, and<br>the location of anneals. For both the 2.2 and 1.1 GeV settings, there are significant shifts in <br>the x and y beam position (2mm or more). She showed the average and standard deviation <br> of epics readings for the LHRS septum current for each run. For several runs, there are small <br>number of epics readings that drift from the average current. It's not clear if this is the <br>current is actually changing or if it is a readout problem. She will look into the yield vs time<br>to try to determine this. JP suggested making a raster cut on the center of the beam to get<br> rid of any potential scraping. Pengjia says there is a way to cut on raster size, but there will<br> be an additional BPM uncertainty. Melissa will discuss this more offline with Pengjia. More<br>details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_07_22.pdf here].<br />
<br />
*Pengjia<br />
**Gave an update on calculating asymmetries/cross sections using the MAID model. This time, <br>he used the Bosted model to get the unpolarized cross sections for the proton. Using unradiated <br>cross section models, he still saw a factor of 6 difference when compared with data. Ryan also <br>calculated asymmetries using unradiated models, and the results were consistent with Pengjia's, <br>so it seems the radiative effects contribute significantly to the factor of 6 difference. More <br>details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07222015/MAID_update_20150722.pdf here].<br />
<br />
<br />
==7/15/2015==<br />
<br />
Present: JP, Min, Chao, Jixie, Melissa <br><br />
By Phone: Ryan, Toby, Ellie, Karl, Vince, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Chao<br />
**Doing a check of simulation/data results for the 2.2 GeV, longitudinal setting in order <br>to check that the optics calibration matrix will work for all momentum settings (not <br>just elastic). He showed a comparison for several different momentum settings.<br> Vince suggested simulating more events, since the statistics start to drop off for <br>lower momentum settings. In general, the data is broader then the result from<br>simulation. In the &theta; distribution, the "tails" seen in the data are not symmetric. JP<br> suggested carefully selecting cuts to remove any background from the data to <br>ensure a good comparison with simulation. More details can be seen in his <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150715/Chao_WeeklyMeeting_07152015.pdf here].<br />
<br />
*Pengjia<br />
**More discussion on Pengjia's [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07082015/MAID_update_20150708.pdf slides] from last week. Pengjia has seen a factor of <br>six difference between his asymmetry calculated from data compared to the <br>asymmetry determined using the MAID model. Ryan did not see this factor of six <br>in his study, but in addition to using radiated XS models, he is using a combination <br>of the Bosted and MAID models (Pengjia is using just the MAID model). Karl <br>commented that the XS from MAID is not very good for our kinematics. Pengjia <br>also showed an estimated NH3 XS. JP commented that it was surprising that the <br>delta peak wasn't visible. Pengjia will look into this for next time.<br />
<br />
<br />
==7/8/2015==<br />
<br />
Present: JP, Min, Chao, Melissa <br><br />
By Phone: Toby, Vince <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Pengjia<br />
**Working on comparing asymmetries determined from MAID to those calculated from <br>data; last time he showed a factor of 6 difference between the two results. This <br>time, he showed two different methods for calculating the differential XS from the <br>virtual photon XS. The first method calculates the differential XS directly from <br>the virtual photon XS, and the second method calculates the differential XS using <br>F<sub>1</sub>, F<sub>2</sub>, g<sub>1</sub> and g<sub>2</sub>. He also showed two different methods for calculating the <br>asymmetry from the virtual photon XS; one method uses A<sub>1</sub> and A<sub>2</sub>, while the other <br>is calculated from the virtual photon XS. There was a discrepancy between the two <br>methods, but he found that there was actually a mistake in one of the equations. <br>While the results from the two methods agree with each other, they are still a factor <br>of 6 larger than the results from data. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07082015/MAID_update_20150708.pdf here].<br />
<br />
*Toby<br />
**Showed an update of his scattering angle study for model reconstruction. He is <br>using BPM and optics data to determine the scattering angle. He showed an example <br>of the calculated scattering angle; JP questioned whether the range was really from <br>0-16 deg. Toby pointed out that there really aren't many events at the boundaries, <br>the distribution is peaked between 4.5-9 deg. He then uses this scattering angle as<br>input for the Bosted model. At low &nu; the simulation results match reasonably well<br>with the data, but the discrepancy starts to become larger as &nu; increases. He took <br>a closer look at the reconstructed scattering angle for each central momentum, and <br>found that a second peak is visible for smaller values of p0. If this second peak was <br>real, the simulation should recreate the data, so this could suggest a problem with <br>the reconstruction. However, Chao pointed out that, for this energy setting, the optics <br>calibration is not complete (currently using the longitudinal optics matrix), so the <br>reconstructed &theta; and &phi; may not be correct yet. For next time, Toby will test this <br>analysis using the 1.7 GeV setting, which has calibrated optics. More details can <br> be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/scatangle_talk.pdf here].<br />
<br />
*Melissa<br />
**Gave a summary of packing fraction analysis. For some settings, the variation in the <br>yields (and P<sub>f</sub>) is due to a fluctuation in the beam position. This will hopefully be<br>resolved by Jie's beam position/acceptance study. For the 2.2 GeV, 2.5T transverse setting<br> there is also an issue of a shift in &nu; between runs. For the 1.1 GeV, 2.5T transverse <br>setting, the yields vary depending on the beam current used for each run. JP suggested <br>a few things to check as the possible cause for these discrepancies including drift in the <br>BCM calibration, anneals of the target material, drift in field (HRS or septum), etc. She <br>has posted a technote draft [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Technotes/PF_technote_draft.pdf here], feedback would be appreciated. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_07_08.pdf here].<br />
<br />
*Min<br />
**Gave an update on her acceptance study. Last time, she showed that the simulation results <br>are more narrow than the data. For this time, she tried cutting on just the center hole, <br>and found that the dp distribution from data better matched the simulation. JP suggested <br>cutting on each of the different holes individually to determine which hole causes the dp <br>distribution to be wider. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07082015/07062015.pdf here].<br />
<br />
*Chao<br />
**Gave an update on optics analysis, currently checking whether simulation results match <br>with data, starting with optics data. First he checked whether the geometry was correct, <br>some deviation was found in the recent optics meeting. The position of the BPMs is hard-<br>coded into the simulation, and the drifting algorithm is used to drift the electrons <br>backward to the BPMs to simulate the readout of BPM A and B. He compared the &theta; <br>distribution before drifting in the target field using a fixed and non-fixed BPM location. <br>The results using a fixed BPM match well with the data. He is currently working on <br>checking this for all momentum settings, and will follow up with Pengjia about the BPM <br>problem. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150708/Chao_WeeklyMeeting_07082015.pdf here].<br />
<br />
<br />
==7/1/2015==<br />
<br />
Present: Chao, Vince, Jie, JP, Min, Melissa <br><br />
By Phone: Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Min<br />
**Gave an update on acceptance studies. She showed a summary table of each energy <br>setting and septum configuration. There hasn't been any problems in the 2.2 GeV, 5T <br>longitudinal and 1.7 GeV, 2.5T transverse settings, but some settings (2.2 GeV, 2.5T <br> transverse, 1.2 GeV, 2.5T transverse and 2.2 GeV, 5T transverse) have a discrepancy <br>in the focal plane between data and simulation. She compared the data divided by the <br>Mott XS to the simulation results without XS, and found that the simulation results <br>of &theta; and &phi; are narrower then the data. JP commented that, while including the Mott<br>XS might change the shape of the distribution, it shouldn't change the boundary. She <br>work on figuring out the cause for this discrepancy before calculating the acceptance. <br>More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07012015/07012015.pdf here].<br />
<br />
*Pengjia<br />
**Comparing asymmetries determined from the MAID model to those calculated from data.<br>Last time he showed a factor of 6 difference between the two results. He determined the <br>scattering angle and Q<sup>2</sup> by fitting the data and compared them to the quantities calculated <br>from MAID. He also showed the results of calculating the quantities g<sub>1</sub>, g<sub>2</sub>, F<sub>1</sub>, F<sub>2</sub>, A<sub>L</sub>, A<sub>T</sub>,<br> dXS<sub>L</sub>, dXS<sub>T</sub>, XS<sub>tot</sub> andXS<sub>mott</sub> using MAID. He hasn't included radiative corrections in his <br>calculations, but this probably won't account for the factor of 6. More details can be seen <br>in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07012015/MAID_20150701.pdf here].<br />
<br />
<br />
----<br />
<br />
==Jan-June 2015==<br />
[[Minutes_Jan2015_to_June2015]]<br />
----<br />
<br />
==July-Dec 2014==<br />
[[Minutes_July2014_to_Dec2014]]<br />
----<br />
<br />
==Jan-June 2014==<br />
[[Minutes_Jan2014_to_June2014]]<br />
----<br />
<br />
==June-Dec 2013==<br />
[[Minutes_June2013_to_Dec2013]]<br />
----<br />
<br />
==Jan-May 2013==<br />
[[Minutes_Jan2013_to_May2013]]<br />
----<br />
<br />
==April-Dec 2012==<br />
[[Minutes_Apr2012_to_Dec2012]]<br />
----<br />
<br />
==Jan-March 2012==<br />
[[Minutes_Jan2012_to_Mar2012]]<br />
----<br />
==July-Dec 2011==<br />
[[Minutes_July2011_to_Dec_2011]]<br />
----<br />
==Jan-June 2011==<br />
[[Minutes_Jan2011_to_June_2011]]<br />
----</div>Melissachttps://hallaweb.jlab.org/wiki/index.php?title=G2p_Analysis_Minutes&diff=26334G2p Analysis Minutes2015-11-18T15:02:15Z<p>Melissac: /* 11/11/2015 */</p>
<hr />
<div>Minutes of the weekly analysis meetings<br />
----<br />
[https://hallaweb.jlab.org/wiki/index.php/G2p_Weekly_Analysis Agenda]<br />
<br />
==11/11/2015==<br />
<br />
Present: JP, Melissa <br><br />
By Phone: Vince, Toby, Ryan, Chao, Min, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Showed "very preliminary" results for g1/g2. She is using a dilution factor determined from <br>the Bosted model, and using the average value of the packing fraction for each material. For the <br>radiative corrections, she is using a model prediction for the asymmetry where the polarized piece <br>comes from the MAID model and the unpolarized cross section is the Bosted model. The difference <br>between the model prediction ''without'' radiative effects and the model prediction ''with'' radiative effects <br>is used as an additive correction to the asymmetry. There was some concern over the large effect <br>of the R.C. at high W. Ryan commented that the final R.C will be large, so they will need to be done<br>very carefully. A cross check with EG1 data will be helpful. In order to match the kinematics of the<br>longitudinal and transverse settings, she scaled the asymmetry by the ratio of the unpolarized cross<br>section at the two different kinematic settings. JP commented that this is not valid, and suggested <br>using model input for the asymmetries, instead of trying to match the kinematics between the data<br>taken in the longitudinal and transverse settings. Next she will work on updating systematics for the <br>asymmetries and structure functions. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/g1_g2/g1g2_11_10.pdf here].<br />
<br />
*Chao<br />
**Gave an update on optics analysis. Comparisons of the data with simulation revealed that there <br>were offsets in the reconstructed kinematics. This correction could be fixed using a finely-tuned<br>fitting procedure. The longitudinal setting has already been fixed, today he showed the results <br>for the 1.7 GeV, transverse setting. He showed the results of doing the calibration; most of the <br>holes near the center have a difference of less than 0.5 MeV between data and simulation. He is <br>currently working on finishing the other transverse settings. More details can be found in his <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20151111/Chao_WeeklyMeeting_11112015.pdf here].<br />
<br />
==11/4/2015==<br />
<br />
Present: Min, Jixie, Melissa <br><br />
By Phone: Chao, Vince, Toby, Ryan, Alex, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Ryan<br />
**Gave an overview of g2p elastic tail and angle reconstruction. The elastic tail is highly sensitive<br>to the scattering angle, so his goal is to develop a method to include these variations in the elastic <br>tail subtraction. He started by looking at the simplest case, helium dilution runs. Using his method, <br>he looked at the elastic tail across a series of different momentum settings, andfound that the tail <br>was not continuous, which he assumed was due to variations in the scattering angle. He did a pseudo-<br>simulation using the Bosted model and varying the scattering angle to confirm the "jump" seen in the <br>elastic tail. However, when he looked at the normalized yields for this same data, he did not see the <br>same discontinuity. This suggests there might be a problem with the scattering angle reconstruction. <br>Chao mentioned that the reconstruction code has been updated (at least for the longitudinal setting) <br>the last replay; he will provide this code to Toby so he can do another replay. Details of the method <br>and cuts used can be seen in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_11415.pdf here].<br />
<br />
*Jie<br />
**Gave an update on his simulation study to understand the beam dependence on the yields. He used the <br>beam position and raster size as input to g2psim, and included radiative and acceptance effects. In <br>general, he found there is a much larger dependence on the beam position using a rastered beam <br>compared to a point beam. He summarized his results for various different momentum settings and found <br>that, in some cases, his results matched what we saw in the data, but not in all cases. Vince suggested <br>testing how much the beam position would need to be changed (for a given momentum setting) to match <br>the simulation with the data. The details of his study can be found in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/yields_update_2015_11_04.pdf here], he is also compiling <br>a technote on this analysis.<br />
<br />
==10/28/2015==<br />
<br />
Present: JP, Min, Kalyan, Melissa <br><br />
By Phone: Alexandre, Vince, Jie, Ryan, Toby, Ellie, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Gave an overview of contributions to the systematic uncertainty for the asymmetry. There are <br>several contributions which are very small (<0.1%) including the charge asymmetry, livetime <br>asymmetry and pion contamination. The target polarization uncertainty was surprisingly small.<br>The values currently listed in the mysql DB for this quantity appear to be incorrect; Toby will<br>update these values. For the contribution from the dilution factor and radiative corrections, she<br> assigned 5% as a placeholder until a better estimate could be made. Karl/Ryan commented <br>that 5% uncertainty on the radiative corrections may be too small, 10-15% would be a better<br>estimate at this point. The tables shown for the longitudinal and transverse settings represent<br>an overestimate of the uncertainty; in the long-term this could be looked at more carefully to<br>decrease the overall systematic uncertainty. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Asym/Asym_10_28.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*There has been a request from the Hall A CC to have an update on g2p at the winter collaboration <br>meeting. Ellie and Jie are both interested, they will check the dates of the meetings to see if they <br>are available.<br />
<br />
==10/14/2015==<br />
<br />
Present: JP, Min, Jixie, Kalyan, Melissa <br><br />
By Phone: Alexandre, Vince, Jie, Todd, Haiyan, Pengjia, Karl, Toby, Ryan, Xiaochao, Nilanga, Chao <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Karl<br />
**Went over the goals of the collaboration meeting:<br />
***Discuss physics topics for students graduating soon<br />
***Identify major remaining physics topics<br />
***Establish a policy for the release of plots<br />
**Suggested a policy for collaboration release of physics results, including specific requirements <br>for moving from "very preliminary" to "preliminary" to "final" results. Details can be seen in his <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/slifer/2015/slifer_g2pcollab_101415.pdf here], and they will be circulated to the g2p mailing list with some small modifications.<br />
<br />
*Pengjia<br />
**Will be defending next Wednesday (Oct. 21st). He showed a "very preliminary" physics <br> asymmetry for the 2.2 GeV 5T setting (both longitudinal and transverse) with a comparison to <br> a radiated model prediction. He used this result to extract a preliminary value for g1 and g2,<br>using the Bosted model as input for the cross section. This result does not include radiative<br>corrections. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/graduate_2015.pdf here].<br />
<br />
*Min<br />
**Showed an overview of status of acceptance study; the overall goal is to match the simulation<br>results to the data, so that the simulation can be used to calculate the acceptance. She<br>described the various attempts to correct the simulation results to match the data. Adjusting the<br> apertures based on optics data works well, but the other two methods (adjusting the apertures <br>based on dilution data and adjusting the acceptance cuts after removing the Mott XS from the <br>data) only work well around the target run. In addition, the simulated yield has a different shape <br>than the data, so the simulation must be adjusted to match this. She will go through this process <br>again once Chao is finished with the optics correction. She is planning to graduate next January, <br>and would like to include a cross section difference for one kinematic setting in her thesis. More <br>details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/collab/10142015_collab_Min.pdf here].<br />
<br />
*Melissa<br />
**Gave an overview of packing fraction analysis. Of the 5 total settings there are 3 that are reasonably <br>stable with some small drifts in yields, and 2 settings that have larger problems. During the 2.2 GeV, <br>2.5T setting the raster size was changed, which could possibly be corrected by applying a cut on<br>the center of the raster. The 1.1 GeV setting has large variations in the elastic yields; some of these <br>runs were taken at low currents (8-20nA), so the beam position information is not reliable. She also <br>showed the results of a pion asymmetry study. Although the pion asymmetry is very large, the <br>residual pion contamination after PID cuts are applied is very small, so the correction is not large. <br>She has scheduled her defense for December 4th, and would like to include a preliminary result <br>for g1,g2 in her thesis. To include a fully corrected result she will need preliminary radiative <br>corrections and dilution results, which she will work with Ryan and Toby to get. More details can <br>be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/talks/MCummings_CollabMeeting_20151013.pdf here].<br />
<br />
*Toby<br />
**Showed a preliminary dilution value that he had shown previously, and described several issues <br>with the result. These issues include that the model assumes a constant scattering angle, and does <br>not include some acceptance effects that are seen in the data. He has been working on correcting <br>these issues by incorporating a scattering angle from data into the model and applying acceptance <br>cuts to the data to remove acceptance effects. He showed the result of applying the acceptance cut <br>across all kinematics for the 5T longitudinal setting; including the acceptance cut gets rid of some of <br>the strange structure seen in the yields, such as the sawtooth pattern seen at high nu. The downside <br>of this method is that the acceptance cut causes a large loss in statistics. He is currently working on <br>trying to re-incorporate some of the lost statistics from the acceptance cut. More details can be seen <br>in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/collaborationupdate.pdf here].<br />
<br />
*Jie<br />
**Gave an update on his study using simulation to understand the drifts in yields. He looked at several <br>momentum settings in the 2.2 GeV, 2.5T setting that had variation in the yields. He varied the beam <br>position along the horizontal and vertical directions using both a point beam and rastered beam. He <br>generated a table summarizing the results using a Monte Carlo method, cross checking with averaged <br>acceptance. His results were similar to his previous test using only the Bosted model; some results <br>agree with what was seen in the data, some have the opposite sign. He will write up his method and <br>results in a technote. He is planning to graduate in summer of 2016. More details can be seen in his <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_10_09_simulation/2015_10_14_collaboration_meeting.pdf here].<br />
<br />
*Chao<br />
**Gave an update on optics analysis. Comparisons of simulation with data revealed that the <br>reconstructed kinematics have some offset. A correction was added to the reconstructed kinematics <br>(vs beam position) and he is currently working on merging this correction into the database with a <br>finely tuned fitting procedure. The problem is that the horizontal beam position shifts the dp <br>reconstruction. He showed the results of applying the new optics matrix which corrects for this shift. <br> He will apply this method to all kinematic settings and study the uncertainty of the optics. Once this <br>is done he will write a NIM paper for g2p optics. He plans to graduate in February/March and would <br>like to include the cross section difference for one or two settings with tuned acceptance and model <br>inputs to obtain a physics result. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20151014/Chao_WeeklyMeeting_10142015.pdf here].<br />
<br />
*Ryan<br />
**Since the last collaboration meeting he has improved the model tuning procedure by using an <br>automated procedure instead of tuning the model by hand. He has tested this using carbon data <br>from the UVa database and will run it for nitrogen data once he has updated saGDH N2 cross <br>sections from Vince. He also updated the systematic error study for inelastic unpolarized radiative <br>corrections by separating the integration/iteration error from the interpolation error. He has the <br>polarized radiative correction code running, and has completed a systematic uncertainty study on <br>the inelastic radiative corrections. He is also working on evaluating physics quantities using models, <br>specifically the hyperfine splitting calculation. He plans to graduate in summer/fall of 2016 and would <br>like to include full radiative corrections on g2p polarized cross sections in his thesis. More details can<br> be seen in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_101315.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*Important to do cross checks of results between students (ex. asymmetries)<br />
*Must be careful to include details of any physics results (whether radiative corrections are included,<br>dilution factor, model input instead of data, etc.)<br />
<br />
==9/30/2015==<br />
<br />
Present: JP, Kalyan, Jixie, Min <br><br />
By Phone: Pengjia, Toby, Ryan, Vince, Jie, Chao, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Toby<br />
**Showed an update on his acceptance/dilution study. He continued with the study of the cuts on the <br>reconstructed &theta; vs &phi; distribution at the target. He scanned several different &theta; vs &phi; cuts to see how <br>the acceptance effects the scattering angle and resulting yields. It turns out the small angle region is <br>influenced by the acceptance a lot but the center region gives a good agreement to the model. He <br>also loosed the center cut to &theta; ~ ± 40 mrad and &phi; ~ ± 10 mrad, the data still agreed with the model. <br>He then recalculated the dilution factor for 2.254 GeV longitudinal setting. More details on his <br>acceptance cuts and method can be found in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/diltalk_093015.pdf here].<br />
<br />
<br />
==9/23/2015==<br />
<br />
Present: JP, Kalyan, Min, Melissa <br><br />
By Phone: Pengjia, Toby, Ryan, Vince, Jie, Chao, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Pengjia<br />
**Showed the structure of his code to create a radiated model of the MAID and Bosted <br>models, based on Ryan's radiative correction work. He showed the breakdown of the <br>different components to the radiated model (internal, external and elastic tail). He used<br> the radiated model to calculate an asymmetry and cross section differences, which he <br> compared with data. Finally, he combined asymmetries calculated from data with the <br>Bosted model cross section to calculate a value for g1 and g2, which he compared <br>with values of g1/g2 determined using the MAID model. More details can be seen in <br>his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/09222015/asym_g12.pdf here].<br />
<br />
*Min<br />
**Gave an update on acceptance studies. Last time, she found that by adjusting the<br>apertures in the simulation she could match the data/simulation results for dp (for one <br>momentum setting). She tested this method for other momentum settings and found <br>that it did not work as well. She also showed a comparison of the yield spectrum for<br>helium runs in the 1.7 GeV setting; the shape of the two distributions are quite <br>different, which might suggest that the model deviates significantly form the data. In<br>the simulated results she saw several "bumps" in the yield, which correspond to the<br>location of resonances. She will update these results when the optics corrections are <br>complete. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/09232015.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*We would like to schedule another collaboration meeting in the near future. The <br>meeting is tentatively scheduled for Wednesday October 14th during our usual meeting <br>time (10am-12pm).<br />
*The purpose of the meeting is to:<br />
**Discuss student thesis topics (particularly any updates from the last <br>collaboration meeting)<br />
**Establish a procedure for presentation/release of collaboration plots/results<br />
*Each student should prepare a few slides (~5 minutes) to show analysis progress<br />
<br />
<br />
==9/16/2015==<br />
<br />
Present: Min, JP, Jixie, Melissa <br><br />
By Phone: Vince, Jie, Chao, Pengjia, Alex, Ryan, Toby, Ellie <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Jie<br />
**Gave an update on his simulation study using MUDIFI. Last time he showed that he uses a<br>least square fit to go from endplane to endplane. For the g2p simulation, it's used to go from<br>(x,y,&theta;,&phi;,dp) in the target plane to (x,y,&theta;,&phi;,dp) in the focal plane. SNAKE produces (x,y,&theta;,&phi;,dp)<br>data in both planes and a polynomial function can be used to determine the relationship<br>between the two planes. First the maximum power for each variable is determined, symmetries<br>are included (if applicable), then the priority of each function must be determined. A Gram-<br>Schmidt transformation is used to do the minimization, and the final step is to decide whether<br>to accept the function f<sub>i</sub>. JP/Vince asked how the priority for each function is chosen, since the<br>choice could introduce some ordering dependence. Since we don't have enough data to<br>constrain, JP suggested introducing some physics. He also suggested getting rid of dp in the<br>focal plane (since it is really just dp in the target plane) so that there is one less dimension to<br>fit. More details can be seen in Jie's slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_09_15_simulation/2015_09_15_Simulation_update.pdf here].<br />
<br />
*Ryan<br />
**Gave an update on evaluating physics quantities using models. His goal was to do a<br>comparison of the hyperfine splitting calculation in C. Carlson's 2006/2008 paper using MAID<br>and Hall B models. Previously he showed a comparison using the Hall B model, where he saw<br>good agreement between his calculation and Carlson's result. For this time he also did a<br>comparison using the MAID model. There is a large difference between the two models for the<br>value of the integrand of &Delta;<sub>2</sub>, over the full range of Q<sup>2</sup>. JP suggested comparing the value of g2<br>between the two models, instead of &Delta;<sub>2</sub>. More details can be seen in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_091615.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*Toby<br />
**Last time he showed a comparison between data and cross sections calculated using the<br>Bosted model (seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/acceptance_scatangle.pdf here]). The model was not continuous for one momentum setting. It <br>turns out the BPM was not recording for that setting, so he re-calculated the XS using<br>values for &theta; and &phi; from surrounding runs and found that the result was now consistent with<br>the neighboring momentum settings. He also played around with the acceptance cuts he<br>showed, and found a region using the "extreme cut" where the sawtooth pattern go away<br>and the yields become flat.<br />
<br />
<br />
==9/9/2015==<br />
<br />
Present: Min, JP, Jixie, Melissa <br><br />
By Phone: Vince, Jie, Chao, Ryan, Toby, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Jie<br />
**Gave an overview of his simulation study using SNAKE and MUDIFI. Using SNAKE, the<br>idea is to trace the particle trajectory in a series of free boxes, then an endplane can be<br>defined within the free boxes to determine the trajectory from endplane to endplane. In<br>g2psim this will be used to trace the trajectory between the sieve plane and the focal<br>plane. There are two important issues to consider, the magnetic field in the free boxes,<br>and the transportation method between the two endplanes. A Runge-Kutta method is <br>used for the transportation, and an adaptive method (which changes with field size and<br>gradient) is used to determine the step size. For the magnetic field, a 3D Tosca field<br>map is used for the septum, and an analytic model is used for the spectrometer magnets. <br> He also described the method for choosing the transportation function to determine the <br>25 matrix terms for each kinematic variable (up to 4th order). JP asked how to determine <br>which order is more important, and cautioned to be careful not to over fit the data. He and<br>Jie will discuss this more offline. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_09_09_simulation_update/2015_09_09_Simulation%20update.pdf here].<br />
<br />
*Chao<br />
**Gave an optics status update. The current problem is that changes in the horizontal beam<br>position changes the dp reconstruction. This was fixed by applying a linear correction in<br>BPM-x and BPM-y to &theta;, &phi; and dp. Applying this correction made the data/simulation <br>agree, but it is still necessary to understand the correction. Using dp scan data with beam<br>position scan data still leaves an offset in &theta; and &phi;. He also tried two other methods to do<br>the calibration. Method 1 uses the central hole to determine a constant offset, uses the<br>horizontal beam position scan data to determine all the matrix elements related to y, and<br>uses dp scan runs to fit the additional matrix elements. Method 2 uses beam position<br>scan data to determine the matrix elements that are not related to x<sub>fp</sub>. Neither of these<br>methods works very well, even when the fitting order of the matrix elements are adjusted.<br>He will continue to check more fitting procedures. More details can be found in his slides <br>[http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150909/Chao_WeeklyMeeting_09092015.pdf here].<br />
<br />
*Pengjia<br />
**Gave an update on comparing asymmetries from data/models for the 2.2 GeV, 5T <br>longitudinal setting. He first radiated the Bosted model XS; he showed the break down of<br>the different radiative corrections including the elastic tail (internal and external) and the<br>radiative effects from inelastic scattering. He showed a comparison with Ryan's results<br>which had good agreement, though there is some deviation when he used different proton<br>form factors (provided by Moshe). In order to compare the asymmetry result with data, he<br>needs to do the radiative corrections for the polarized MAID model, which he will continue<br>to work on. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/09092015/asym_20150909.pdf here].<br />
<br />
<br />
==9/2/2015==<br />
<br />
Present: JP, Min, Kalyan, Melissa <br><br />
By Phone: Vince, Alex, Jie, Chao, Ryan, Toby, Ellie, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Gave an update on determining the correction to asymmetries for pion contamination. <br>Previously, she used the 2.2 GeV, 5T longitudinal setting as an example, for this time <br>she used the transverse configuration, as it has the largest pion contamination. She <br>modified her method for differentiating between electrons and pions; previously she <br>identified pions as events that do not trigger the Cherenkov, this time she used a cut <br>below the single photo electron peak to select pions. JP suggested using stricter cuts <br>for selecting pions when determining the pion asymmetry, to make sure it is a clean <br>sample. Although this setting has a large pion contamination, the number of pion<br> events that remain after lead glass cuts are applied is low, so the overall correction <br>is very small. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Pion/PionAsym_08_31.pdf here].<br />
<br />
*Min<br />
**Gave an update on acceptance tuning. She looked at results from the 1.7 GeV setting <br>and found that the height of the peaks is different between data and simulation for <br>different holes in the sieve slit. Looking at the &theta; vs &phi; distribution, she noticed on the<br>positive &theta; side there were fewer holes in simulation than in data, and on the negative <br> &theta; side there were more holes in simulation compared to data. She tried adjusting the<br>aperture cuts by changing the physical location of the Q1, Q2 and septum planes to <br>uncover events that were previously blocked. After the adjustment, the data/simulation <br>results agreed much better. She showed a similar procedure for a dilution run and was<br>able to see better agreement between data/simulation after the aperture adjustments <br>were made. JP/Vince suggested being cautious when adjusting the aperture cuts, as<br> the apertures should be well defined already. They suggested adjusting things that are<br> less well known first, such as the septum field. More details can be seen in her slides<br>[http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/09022015.pdf here].<br />
<br />
*Ryan<br />
**Working on generating physics quantities using models to eventually compare with data.<br>So far, he has incorporated the MAID2007 and Hall B models. He calculated the <br>hyperfine splitting quantities &Delta;1 and &Delta;2 using the Hall B EG1 model and compared them<br> to the results in C. Carlson's 2006 paper. His results agreed very well, he only saw a<br> small deviation for &Delta;2 in the lowest Q<sup>2</sup> range. To check that nothing strange was going <br> on in the low Q<sup>2</sup> range, he calculated &Delta;2 for various small ranges around zero, to ensure<br>that the integration method is well behaved. The Carlson paper also includes calculations <br>using the Simula model, he would like to do a check of this method as well, but is unsure <br>where to find the Simula model. Since he was able to reproduce the hyperfine splitting <br>result, he is confident in his calculation method; it should be straightforward to calculate <br>other spin structure function integrals. More details on his method can be found in his <br>slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_09215.pdf here].<br />
<br />
*Toby<br />
**Showed an update on his acceptance/scattering angle study. He applied cuts of varying<br>strictness on the reconstructed &theta; vs &phi; distribution at the target. He then calculated the <br>real scattering angle before/after scattering for each cut. Using these scattering angles <br> as inputs for the Bosted model he was able to calculate the XS and compare it to data.<br>He showed the comparison between data/Bosted model for each acceptance cut. He <br>hoped that the more extreme acceptance cuts on the data would flatten the yield <br>distribution, but it actually just enhanced the sawtooth pattern. JP questioned why the <br>Bosted prediction for one momentum bin (the green one) was so much lower than the<br> neighboring ones. Toby said the only input that goes into the model is the scattering angle,<br> so it must be considerably different for this momentum setting. He also commented that<br>the model prediction is scaled to match the data, so the scaling enhances the jump in<br>the model. More details on his acceptance cuts and method can be found in his slides<br>[http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/acceptance_scatangle.pdf here].<br />
<br />
<br />
==8/26/2015==<br />
<br />
Present: Jixie, Alex, Min, Kalyan, JP, Chao, Melissa <br><br />
By Phone: Vince, Jie, Ryan, Toby, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Chao<br />
**Gave an update on optics studies. Previously, he showed a comparison between optics data <br>and simulation where he cut on individual sieve holes. For this week, he included a cut on y <br>and dp that he didn't include previously. In the plot of &theta; vs y, JP pointed out that there were <br>additional tails on some sieve holes, Chao says these tails go away when the &phi; cut is <br>included. He showed a 2D plot of &theta; vs &phi;, along with the 1D projection of these variables. JP<br>commented that the data is more smeared out than the simulation, so it is difficult to compare <br>data with simulation results. It's possible that some of the smearing comes from events that <br>punch through the sieve slit and are not being cut out (the simulation currently assumes these <br>events are stopped by the sieve). Looking at the center hole, the data/simulation agree <br>reasonably well, but the agreement gets worse for holes on the edge of the sieve slit. Chao<br>will continue to look into this. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150826/Chao_WeeklyMeeting_08262015.pdf here].<br />
**He also mentioned that ~1 month ago he reported a problem with the [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150708/Chao_WeeklyMeeting_07082015.pdf BPM simulation].<br>He found it was actually a problem with the simulation itself, which has now been updated <br> to correct the problem.<br />
<br />
<br />
'''General Discussion:'''<br />
*Pengjia has submitted his BPM NIM paper.<br />
<br />
<br />
==8/19/2015==<br />
<br />
Present: Chao, Jie, Min, Jixie, Kalyan, Melissa <br><br />
By Phone: Vince, Ryan, Toby, Karl, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Showed a method for determining the correction to asymmetries for pion contamination. The <br>measured asymmetry can be written in terms of the electron and pion asymmetries, multiplied <br>by the fraction of events of that particle. To differentiate between electrons and pions, a cut is<br>made on events that trigger the Cherenkov detector (electrons) and events that do not trigger<br>the Cherenkov (pions). Kalyan commented that this method of selecting pions may be too blind,<br> and suggested making a 2D cut on E/p vs Cherenkov instead. To determine the fraction of<br>electrons/pions, "good event" cuts are applied (loose acceptance cuts, single track events and<br>pion rejector cuts) and the number of electrons/pions that survive the cuts are counted. Although<br>the pion asymmetry is much larger than the electron asymmetry, the number of residual pions<br>is very small, so the overall correction is small. For this example the 2.2 GeV, 5T longitudinal<br>setting was used, but the correction may be larger for the 5T transverse settings, which she <br>will do next. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Pion/PionAsym_08_19.pdf here].<br />
<br />
*Min <br />
**Gave an update on acceptance studies. She used the 1.7 GeV, 2.5T setting (with 3rd septum <br>configuration) to test the acceptance cuts using the yield ratio of data to simulation. She <br>showed a plot of target &theta; vs &phi; for both data and simulation, and applied a graphical cut to get<br>rid of events on the edges. Looking at the resulting 1D plots shows reasonable agreement<br>between &theta; and &phi;. Vince pointed out that there seems to be some additional structure in the<br>dp distribution, and suggested expanding the &delta; cut out to &pm; 4% to see if there is more <br>hidden structure. Min said she has seen this in other settings as well and will look into it. She<br>also tried adjusting the cuts on &theta;, &phi; and &delta; and looked at how the ratio of yields from data/<br>simulation changed; the ratio starts to drop off as the cuts get wider. Next she will work on<br>calculating the yields using W bins. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/08192015.pdf here].<br />
<br />
<br />
==8/12/2015==<br />
<br />
Present: Jie, Chao, Kalyan, Min, Jixie, Melissa <br><br />
By Phone: Pengjia, Ryan, Toby, Karl, Ellie, Alex <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Chao<br />
**Gave an update on optics studies. Previously, Min has shown comparisons of data/simulation<br> where she looked at different columns of sieve holes. Chao continued this study by cutting on <br>individual sieve holes. Looking at the center sieve hole, the &phi; distribution looks reasonable, but <br>the &theta; distribution has some issues. Specifically, the data is wider on the left side (negative &theta;) <br>than the simulation. He showed results for several sieve holes, including one that was in the <br>row as the center hole, but in the farthest column on the left side of the sieve slit. In this case <br>the &theta; distribution had similar width for both data and simulation, but the height of the simulation<br> distribution was larger. This may suggest that something is wrong with the acceptance in the <br>simulation. The problem with &theta; seems to be systematic; for most of the sieve holes there are <br>more events on the left side of the data than in the simulation. Kalyan asked whether the <br>thickness of the sieve slit was taken into account, Chao says it was included in the simulation <br>and optimizer. Jixie suggested comparing the dp distributions for each sieve hole. More details <br>can be seen in Chao's slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150812/Chao_WeeklyMeeting_08122015.pdf here].<br />
<br />
<br />
==7/29/2015==<br />
<br />
Present: Chao, Min, JP, Melissa <br><br />
By Phone: Alex, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Min<br />
**Gave an update on acceptance studies. Previously, Chao showed a correction for the beam<br>position in g2psim. Min checked this correction by looking at optics runs. On the data she <br>applied a cut on dp (to select elastic events) and on the focal plane (to get rid of junk <br> events). On the simulation, only an aperture cut was applied. She compared the data and<br>simulation results for &theta; and &phi; both before and after drifting from the sieve slit to the target.<br>The effect of the target field on &theta; is not very large, though there is a shift down in angle.<br>However, the shape of the &theta; distribution is different between data and simulation. The<br>effect of the target field on &phi; is significant; it's not clear why this is the case. To try to<br>determine the reason for the discrepancies, she applied a cut along each column of sieve<br>slit holes in &phi; and compared the data and simulation results for &theta;,&phi; and dp. Column 2<br>seems to have the best agreement (for dp), columns 1 and 2 have a shift while columns<br>3-6 have a difference in width. Chao suggested also cutting along each row of sieve slit<br>holes to better study the effect of the drift on &phi;. Min will work on identifying the differences<br>between data and simulation, specifically whether the boundaries are different between<br>the two. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07272015/07292015.pdf here].<br />
<br />
<br />
==7/22/2015==<br />
<br />
Present: JP, Min, Jixie, Melissa <br><br />
By Phone: Alex, Ryan, Toby, Ellie, Karl, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Showed various checks for packing fraction runs that have large discrepancies, including <br>beam position, beam energy, spectrometer central momentum setting, septum current, and<br>the location of anneals. For both the 2.2 and 1.1 GeV settings, there are significant shifts in <br>the x and y beam position (2mm or more). She showed the average and standard deviation <br> of epics readings for the LHRS septum current for each run. For several runs, there are small <br>number of epics readings that drift from the average current. It's not clear if this is the <br>current is actually changing or if it is a readout problem. She will look into the yield vs time<br>to try to determine this. JP suggested making a raster cut on the center of the beam to get<br> rid of any potential scraping. Pengjia says there is a way to cut on raster size, but there will<br> be an additional BPM uncertainty. Melissa will discuss this more offline with Pengjia. More<br>details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_07_22.pdf here].<br />
<br />
*Pengjia<br />
**Gave an update on calculating asymmetries/cross sections using the MAID model. This time, <br>he used the Bosted model to get the unpolarized cross sections for the proton. Using unradiated <br>cross section models, he still saw a factor of 6 difference when compared with data. Ryan also <br>calculated asymmetries using unradiated models, and the results were consistent with Pengjia's, <br>so it seems the radiative effects contribute significantly to the factor of 6 difference. More <br>details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07222015/MAID_update_20150722.pdf here].<br />
<br />
<br />
==7/15/2015==<br />
<br />
Present: JP, Min, Chao, Jixie, Melissa <br><br />
By Phone: Ryan, Toby, Ellie, Karl, Vince, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Chao<br />
**Doing a check of simulation/data results for the 2.2 GeV, longitudinal setting in order <br>to check that the optics calibration matrix will work for all momentum settings (not <br>just elastic). He showed a comparison for several different momentum settings.<br> Vince suggested simulating more events, since the statistics start to drop off for <br>lower momentum settings. In general, the data is broader then the result from<br>simulation. In the &theta; distribution, the "tails" seen in the data are not symmetric. JP<br> suggested carefully selecting cuts to remove any background from the data to <br>ensure a good comparison with simulation. More details can be seen in his <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150715/Chao_WeeklyMeeting_07152015.pdf here].<br />
<br />
*Pengjia<br />
**More discussion on Pengjia's [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07082015/MAID_update_20150708.pdf slides] from last week. Pengjia has seen a factor of <br>six difference between his asymmetry calculated from data compared to the <br>asymmetry determined using the MAID model. Ryan did not see this factor of six <br>in his study, but in addition to using radiated XS models, he is using a combination <br>of the Bosted and MAID models (Pengjia is using just the MAID model). Karl <br>commented that the XS from MAID is not very good for our kinematics. Pengjia <br>also showed an estimated NH3 XS. JP commented that it was surprising that the <br>delta peak wasn't visible. Pengjia will look into this for next time.<br />
<br />
<br />
==7/8/2015==<br />
<br />
Present: JP, Min, Chao, Melissa <br><br />
By Phone: Toby, Vince <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Pengjia<br />
**Working on comparing asymmetries determined from MAID to those calculated from <br>data; last time he showed a factor of 6 difference between the two results. This <br>time, he showed two different methods for calculating the differential XS from the <br>virtual photon XS. The first method calculates the differential XS directly from <br>the virtual photon XS, and the second method calculates the differential XS using <br>F<sub>1</sub>, F<sub>2</sub>, g<sub>1</sub> and g<sub>2</sub>. He also showed two different methods for calculating the <br>asymmetry from the virtual photon XS; one method uses A<sub>1</sub> and A<sub>2</sub>, while the other <br>is calculated from the virtual photon XS. There was a discrepancy between the two <br>methods, but he found that there was actually a mistake in one of the equations. <br>While the results from the two methods agree with each other, they are still a factor <br>of 6 larger than the results from data. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07082015/MAID_update_20150708.pdf here].<br />
<br />
*Toby<br />
**Showed an update of his scattering angle study for model reconstruction. He is <br>using BPM and optics data to determine the scattering angle. He showed an example <br>of the calculated scattering angle; JP questioned whether the range was really from <br>0-16 deg. Toby pointed out that there really aren't many events at the boundaries, <br>the distribution is peaked between 4.5-9 deg. He then uses this scattering angle as<br>input for the Bosted model. At low &nu; the simulation results match reasonably well<br>with the data, but the discrepancy starts to become larger as &nu; increases. He took <br>a closer look at the reconstructed scattering angle for each central momentum, and <br>found that a second peak is visible for smaller values of p0. If this second peak was <br>real, the simulation should recreate the data, so this could suggest a problem with <br>the reconstruction. However, Chao pointed out that, for this energy setting, the optics <br>calibration is not complete (currently using the longitudinal optics matrix), so the <br>reconstructed &theta; and &phi; may not be correct yet. For next time, Toby will test this <br>analysis using the 1.7 GeV setting, which has calibrated optics. More details can <br> be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/scatangle_talk.pdf here].<br />
<br />
*Melissa<br />
**Gave a summary of packing fraction analysis. For some settings, the variation in the <br>yields (and P<sub>f</sub>) is due to a fluctuation in the beam position. This will hopefully be<br>resolved by Jie's beam position/acceptance study. For the 2.2 GeV, 2.5T transverse setting<br> there is also an issue of a shift in &nu; between runs. For the 1.1 GeV, 2.5T transverse <br>setting, the yields vary depending on the beam current used for each run. JP suggested <br>a few things to check as the possible cause for these discrepancies including drift in the <br>BCM calibration, anneals of the target material, drift in field (HRS or septum), etc. She <br>has posted a technote draft [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Technotes/PF_technote_draft.pdf here], feedback would be appreciated. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_07_08.pdf here].<br />
<br />
*Min<br />
**Gave an update on her acceptance study. Last time, she showed that the simulation results <br>are more narrow than the data. For this time, she tried cutting on just the center hole, <br>and found that the dp distribution from data better matched the simulation. JP suggested <br>cutting on each of the different holes individually to determine which hole causes the dp <br>distribution to be wider. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07082015/07062015.pdf here].<br />
<br />
*Chao<br />
**Gave an update on optics analysis, currently checking whether simulation results match <br>with data, starting with optics data. First he checked whether the geometry was correct, <br>some deviation was found in the recent optics meeting. The position of the BPMs is hard-<br>coded into the simulation, and the drifting algorithm is used to drift the electrons <br>backward to the BPMs to simulate the readout of BPM A and B. He compared the &theta; <br>distribution before drifting in the target field using a fixed and non-fixed BPM location. <br>The results using a fixed BPM match well with the data. He is currently working on <br>checking this for all momentum settings, and will follow up with Pengjia about the BPM <br>problem. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150708/Chao_WeeklyMeeting_07082015.pdf here].<br />
<br />
<br />
==7/1/2015==<br />
<br />
Present: Chao, Vince, Jie, JP, Min, Melissa <br><br />
By Phone: Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Min<br />
**Gave an update on acceptance studies. She showed a summary table of each energy <br>setting and septum configuration. There hasn't been any problems in the 2.2 GeV, 5T <br>longitudinal and 1.7 GeV, 2.5T transverse settings, but some settings (2.2 GeV, 2.5T <br> transverse, 1.2 GeV, 2.5T transverse and 2.2 GeV, 5T transverse) have a discrepancy <br>in the focal plane between data and simulation. She compared the data divided by the <br>Mott XS to the simulation results without XS, and found that the simulation results <br>of &theta; and &phi; are narrower then the data. JP commented that, while including the Mott<br>XS might change the shape of the distribution, it shouldn't change the boundary. She <br>work on figuring out the cause for this discrepancy before calculating the acceptance. <br>More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07012015/07012015.pdf here].<br />
<br />
*Pengjia<br />
**Comparing asymmetries determined from the MAID model to those calculated from data.<br>Last time he showed a factor of 6 difference between the two results. He determined the <br>scattering angle and Q<sup>2</sup> by fitting the data and compared them to the quantities calculated <br>from MAID. He also showed the results of calculating the quantities g<sub>1</sub>, g<sub>2</sub>, F<sub>1</sub>, F<sub>2</sub>, A<sub>L</sub>, A<sub>T</sub>,<br> dXS<sub>L</sub>, dXS<sub>T</sub>, XS<sub>tot</sub> andXS<sub>mott</sub> using MAID. He hasn't included radiative corrections in his <br>calculations, but this probably won't account for the factor of 6. More details can be seen <br>in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07012015/MAID_20150701.pdf here].<br />
<br />
<br />
----<br />
<br />
==Jan-June 2015==<br />
[[Minutes_Jan2015_to_June2015]]<br />
----<br />
<br />
==July-Dec 2014==<br />
[[Minutes_July2014_to_Dec2014]]<br />
----<br />
<br />
==Jan-June 2014==<br />
[[Minutes_Jan2014_to_June2014]]<br />
----<br />
<br />
==June-Dec 2013==<br />
[[Minutes_June2013_to_Dec2013]]<br />
----<br />
<br />
==Jan-May 2013==<br />
[[Minutes_Jan2013_to_May2013]]<br />
----<br />
<br />
==April-Dec 2012==<br />
[[Minutes_Apr2012_to_Dec2012]]<br />
----<br />
<br />
==Jan-March 2012==<br />
[[Minutes_Jan2012_to_Mar2012]]<br />
----<br />
==July-Dec 2011==<br />
[[Minutes_July2011_to_Dec_2011]]<br />
----<br />
==Jan-June 2011==<br />
[[Minutes_Jan2011_to_June_2011]]<br />
----</div>Melissachttps://hallaweb.jlab.org/wiki/index.php?title=G2p_Analysis_Minutes&diff=26330G2p Analysis Minutes2015-11-18T14:50:24Z<p>Melissac: /* 11/4/2015 */</p>
<hr />
<div>Minutes of the weekly analysis meetings<br />
----<br />
[https://hallaweb.jlab.org/wiki/index.php/G2p_Weekly_Analysis Agenda]<br />
<br />
==11/11/2015==<br />
<br />
Present: JP, Melissa <br><br />
By Phone: Vince, Toby, Ryan, Chao, Min, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Showed "very preliminary" results for g1/g2. She is using a dilution factor determined from <br>the Bosted model, and using the average value of the packing fraction for each material. For the <br>radiative corrections, she is using a model prediction for the asymmetry where the polarized piece <br>comes from the MAID model and the unpolarized cross section is the Bosted model. The difference <br>between the model prediction ''without'' radiative effects and the model prediction ''with'' radiative effects <br>is used as an additive correction to the asymmetry. There was some concern over the large effect <br>of the R.C. at high W. Ryan commented that the final R.C will be large, so they will need to be done<br>very carefully. A cross check with EG1 data will be helpful. In order to match the kinematics of the<br>longitudinal and transverse settings, she scaled the asymmetry by the ratio of the unpolarized cross<br>section at the two different kinematic settings. JP commented that this is not valid, and suggested <br>using model input for the asymmetries, instead of trying to match the kinematics between the data<br>taken in the longitudinal and transverse settings. Next she will work on updating systematics for the <br>asymmetries and structure functions. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/g1_g2/g1g2_11_10.pdf here].<br />
<br />
*Chao<br />
**Gave an update on optics analysis. Comparisons of the data with simulation revealed that there <br>were offsets in the reconstructed kinematics. This correction could be fixed using a finely-tuned<br>fitting procedure. The longitudinal setting has already been fixed, today he showed the results <br>for the 1.7 GeV, transverse setting. He showed the results of doing the calibration; <br>most of the holes near the center have a difference of less than 0.5 MeV between data and <br>simulation. He is currently working on finishing the other transverse settings. More details can be found in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20151111/Chao_WeeklyMeeting_11112015.pdf here].<br />
<br />
<br />
==11/4/2015==<br />
<br />
Present: Min, Jixie, Melissa <br><br />
By Phone: Chao, Vince, Toby, Ryan, Alex, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Ryan<br />
**Gave an overview of g2p elastic tail and angle reconstruction. The elastic tail is highly sensitive<br>to the scattering angle, so his goal is to develop a method to include these variations in the elastic <br>tail subtraction. He started by looking at the simplest case, helium dilution runs. Using his method, <br>he looked at the elastic tail across a series of different momentum settings, andfound that the tail <br>was not continuous, which he assumed was due to variations in the scattering angle. He did a pseudo-<br>simulation using the Bosted model and varying the scattering angle to confirm the "jump" seen in the <br>elastic tail. However, when he looked at the normalized yields for this same data, he did not see the <br>same discontinuity. This suggests there might be a problem with the scattering angle reconstruction. <br>Chao mentioned that the reconstruction code has been updated (at least for the longitudinal setting) <br>the last replay; he will provide this code to Toby so he can do another replay. Details of the method <br>and cuts used can be seen in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_11415.pdf here].<br />
<br />
*Jie<br />
**Gave an update on his simulation study to understand the beam dependence on the yields. He used the <br>beam position and raster size as input to g2psim, and included radiative and acceptance effects. In <br>general, he found there is a much larger dependence on the beam position using a rastered beam <br>compared to a point beam. He summarized his results for various different momentum settings and found <br>that, in some cases, his results matched what we saw in the data, but not in all cases. Vince suggested <br>testing how much the beam position would need to be changed (for a given momentum setting) to match <br>the simulation with the data. The details of his study can be found in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/yields_update_2015_11_04.pdf here], he is also compiling <br>a technote on this analysis.<br />
<br />
==10/28/2015==<br />
<br />
Present: JP, Min, Kalyan, Melissa <br><br />
By Phone: Alexandre, Vince, Jie, Ryan, Toby, Ellie, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Gave an overview of contributions to the systematic uncertainty for the asymmetry. There are <br>several contributions which are very small (<0.1%) including the charge asymmetry, livetime <br>asymmetry and pion contamination. The target polarization uncertainty was surprisingly small.<br>The values currently listed in the mysql DB for this quantity appear to be incorrect; Toby will<br>update these values. For the contribution from the dilution factor and radiative corrections, she<br> assigned 5% as a placeholder until a better estimate could be made. Karl/Ryan commented <br>that 5% uncertainty on the radiative corrections may be too small, 10-15% would be a better<br>estimate at this point. The tables shown for the longitudinal and transverse settings represent<br>an overestimate of the uncertainty; in the long-term this could be looked at more carefully to<br>decrease the overall systematic uncertainty. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Asym/Asym_10_28.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*There has been a request from the Hall A CC to have an update on g2p at the winter collaboration <br>meeting. Ellie and Jie are both interested, they will check the dates of the meetings to see if they <br>are available.<br />
<br />
==10/14/2015==<br />
<br />
Present: JP, Min, Jixie, Kalyan, Melissa <br><br />
By Phone: Alexandre, Vince, Jie, Todd, Haiyan, Pengjia, Karl, Toby, Ryan, Xiaochao, Nilanga, Chao <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Karl<br />
**Went over the goals of the collaboration meeting:<br />
***Discuss physics topics for students graduating soon<br />
***Identify major remaining physics topics<br />
***Establish a policy for the release of plots<br />
**Suggested a policy for collaboration release of physics results, including specific requirements <br>for moving from "very preliminary" to "preliminary" to "final" results. Details can be seen in his <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/slifer/2015/slifer_g2pcollab_101415.pdf here], and they will be circulated to the g2p mailing list with some small modifications.<br />
<br />
*Pengjia<br />
**Will be defending next Wednesday (Oct. 21st). He showed a "very preliminary" physics <br> asymmetry for the 2.2 GeV 5T setting (both longitudinal and transverse) with a comparison to <br> a radiated model prediction. He used this result to extract a preliminary value for g1 and g2,<br>using the Bosted model as input for the cross section. This result does not include radiative<br>corrections. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/graduate_2015.pdf here].<br />
<br />
*Min<br />
**Showed an overview of status of acceptance study; the overall goal is to match the simulation<br>results to the data, so that the simulation can be used to calculate the acceptance. She<br>described the various attempts to correct the simulation results to match the data. Adjusting the<br> apertures based on optics data works well, but the other two methods (adjusting the apertures <br>based on dilution data and adjusting the acceptance cuts after removing the Mott XS from the <br>data) only work well around the target run. In addition, the simulated yield has a different shape <br>than the data, so the simulation must be adjusted to match this. She will go through this process <br>again once Chao is finished with the optics correction. She is planning to graduate next January, <br>and would like to include a cross section difference for one kinematic setting in her thesis. More <br>details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/collab/10142015_collab_Min.pdf here].<br />
<br />
*Melissa<br />
**Gave an overview of packing fraction analysis. Of the 5 total settings there are 3 that are reasonably <br>stable with some small drifts in yields, and 2 settings that have larger problems. During the 2.2 GeV, <br>2.5T setting the raster size was changed, which could possibly be corrected by applying a cut on<br>the center of the raster. The 1.1 GeV setting has large variations in the elastic yields; some of these <br>runs were taken at low currents (8-20nA), so the beam position information is not reliable. She also <br>showed the results of a pion asymmetry study. Although the pion asymmetry is very large, the <br>residual pion contamination after PID cuts are applied is very small, so the correction is not large. <br>She has scheduled her defense for December 4th, and would like to include a preliminary result <br>for g1,g2 in her thesis. To include a fully corrected result she will need preliminary radiative <br>corrections and dilution results, which she will work with Ryan and Toby to get. More details can <br>be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/talks/MCummings_CollabMeeting_20151013.pdf here].<br />
<br />
*Toby<br />
**Showed a preliminary dilution value that he had shown previously, and described several issues <br>with the result. These issues include that the model assumes a constant scattering angle, and does <br>not include some acceptance effects that are seen in the data. He has been working on correcting <br>these issues by incorporating a scattering angle from data into the model and applying acceptance <br>cuts to the data to remove acceptance effects. He showed the result of applying the acceptance cut <br>across all kinematics for the 5T longitudinal setting; including the acceptance cut gets rid of some of <br>the strange structure seen in the yields, such as the sawtooth pattern seen at high nu. The downside <br>of this method is that the acceptance cut causes a large loss in statistics. He is currently working on <br>trying to re-incorporate some of the lost statistics from the acceptance cut. More details can be seen <br>in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/collaborationupdate.pdf here].<br />
<br />
*Jie<br />
**Gave an update on his study using simulation to understand the drifts in yields. He looked at several <br>momentum settings in the 2.2 GeV, 2.5T setting that had variation in the yields. He varied the beam <br>position along the horizontal and vertical directions using both a point beam and rastered beam. He <br>generated a table summarizing the results using a Monte Carlo method, cross checking with averaged <br>acceptance. His results were similar to his previous test using only the Bosted model; some results <br>agree with what was seen in the data, some have the opposite sign. He will write up his method and <br>results in a technote. He is planning to graduate in summer of 2016. More details can be seen in his <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_10_09_simulation/2015_10_14_collaboration_meeting.pdf here].<br />
<br />
*Chao<br />
**Gave an update on optics analysis. Comparisons of simulation with data revealed that the <br>reconstructed kinematics have some offset. A correction was added to the reconstructed kinematics <br>(vs beam position) and he is currently working on merging this correction into the database with a <br>finely tuned fitting procedure. The problem is that the horizontal beam position shifts the dp <br>reconstruction. He showed the results of applying the new optics matrix which corrects for this shift. <br> He will apply this method to all kinematic settings and study the uncertainty of the optics. Once this <br>is done he will write a NIM paper for g2p optics. He plans to graduate in February/March and would <br>like to include the cross section difference for one or two settings with tuned acceptance and model <br>inputs to obtain a physics result. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20151014/Chao_WeeklyMeeting_10142015.pdf here].<br />
<br />
*Ryan<br />
**Since the last collaboration meeting he has improved the model tuning procedure by using an <br>automated procedure instead of tuning the model by hand. He has tested this using carbon data <br>from the UVa database and will run it for nitrogen data once he has updated saGDH N2 cross <br>sections from Vince. He also updated the systematic error study for inelastic unpolarized radiative <br>corrections by separating the integration/iteration error from the interpolation error. He has the <br>polarized radiative correction code running, and has completed a systematic uncertainty study on <br>the inelastic radiative corrections. He is also working on evaluating physics quantities using models, <br>specifically the hyperfine splitting calculation. He plans to graduate in summer/fall of 2016 and would <br>like to include full radiative corrections on g2p polarized cross sections in his thesis. More details can<br> be seen in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_101315.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*Important to do cross checks of results between students (ex. asymmetries)<br />
*Must be careful to include details of any physics results (whether radiative corrections are included,<br>dilution factor, model input instead of data, etc.)<br />
<br />
==9/30/2015==<br />
<br />
Present: JP, Kalyan, Jixie, Min <br><br />
By Phone: Pengjia, Toby, Ryan, Vince, Jie, Chao, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Toby<br />
**Showed an update on his acceptance/dilution study. He continued with the study of the cuts on the <br>reconstructed &theta; vs &phi; distribution at the target. He scanned several different &theta; vs &phi; cuts to see how <br>the acceptance effects the scattering angle and resulting yields. It turns out the small angle region is <br>influenced by the acceptance a lot but the center region gives a good agreement to the model. He <br>also loosed the center cut to &theta; ~ ± 40 mrad and &phi; ~ ± 10 mrad, the data still agreed with the model. <br>He then recalculated the dilution factor for 2.254 GeV longitudinal setting. More details on his <br>acceptance cuts and method can be found in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/diltalk_093015.pdf here].<br />
<br />
<br />
==9/23/2015==<br />
<br />
Present: JP, Kalyan, Min, Melissa <br><br />
By Phone: Pengjia, Toby, Ryan, Vince, Jie, Chao, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Pengjia<br />
**Showed the structure of his code to create a radiated model of the MAID and Bosted <br>models, based on Ryan's radiative correction work. He showed the breakdown of the <br>different components to the radiated model (internal, external and elastic tail). He used<br> the radiated model to calculate an asymmetry and cross section differences, which he <br> compared with data. Finally, he combined asymmetries calculated from data with the <br>Bosted model cross section to calculate a value for g1 and g2, which he compared <br>with values of g1/g2 determined using the MAID model. More details can be seen in <br>his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/09222015/asym_g12.pdf here].<br />
<br />
*Min<br />
**Gave an update on acceptance studies. Last time, she found that by adjusting the<br>apertures in the simulation she could match the data/simulation results for dp (for one <br>momentum setting). She tested this method for other momentum settings and found <br>that it did not work as well. She also showed a comparison of the yield spectrum for<br>helium runs in the 1.7 GeV setting; the shape of the two distributions are quite <br>different, which might suggest that the model deviates significantly form the data. In<br>the simulated results she saw several "bumps" in the yield, which correspond to the<br>location of resonances. She will update these results when the optics corrections are <br>complete. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/09232015.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*We would like to schedule another collaboration meeting in the near future. The <br>meeting is tentatively scheduled for Wednesday October 14th during our usual meeting <br>time (10am-12pm).<br />
*The purpose of the meeting is to:<br />
**Discuss student thesis topics (particularly any updates from the last <br>collaboration meeting)<br />
**Establish a procedure for presentation/release of collaboration plots/results<br />
*Each student should prepare a few slides (~5 minutes) to show analysis progress<br />
<br />
<br />
==9/16/2015==<br />
<br />
Present: Min, JP, Jixie, Melissa <br><br />
By Phone: Vince, Jie, Chao, Pengjia, Alex, Ryan, Toby, Ellie <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Jie<br />
**Gave an update on his simulation study using MUDIFI. Last time he showed that he uses a<br>least square fit to go from endplane to endplane. For the g2p simulation, it's used to go from<br>(x,y,&theta;,&phi;,dp) in the target plane to (x,y,&theta;,&phi;,dp) in the focal plane. SNAKE produces (x,y,&theta;,&phi;,dp)<br>data in both planes and a polynomial function can be used to determine the relationship<br>between the two planes. First the maximum power for each variable is determined, symmetries<br>are included (if applicable), then the priority of each function must be determined. A Gram-<br>Schmidt transformation is used to do the minimization, and the final step is to decide whether<br>to accept the function f<sub>i</sub>. JP/Vince asked how the priority for each function is chosen, since the<br>choice could introduce some ordering dependence. Since we don't have enough data to<br>constrain, JP suggested introducing some physics. He also suggested getting rid of dp in the<br>focal plane (since it is really just dp in the target plane) so that there is one less dimension to<br>fit. More details can be seen in Jie's slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_09_15_simulation/2015_09_15_Simulation_update.pdf here].<br />
<br />
*Ryan<br />
**Gave an update on evaluating physics quantities using models. His goal was to do a<br>comparison of the hyperfine splitting calculation in C. Carlson's 2006/2008 paper using MAID<br>and Hall B models. Previously he showed a comparison using the Hall B model, where he saw<br>good agreement between his calculation and Carlson's result. For this time he also did a<br>comparison using the MAID model. There is a large difference between the two models for the<br>value of the integrand of &Delta;<sub>2</sub>, over the full range of Q<sup>2</sup>. JP suggested comparing the value of g2<br>between the two models, instead of &Delta;<sub>2</sub>. More details can be seen in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_091615.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*Toby<br />
**Last time he showed a comparison between data and cross sections calculated using the<br>Bosted model (seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/acceptance_scatangle.pdf here]). The model was not continuous for one momentum setting. It <br>turns out the BPM was not recording for that setting, so he re-calculated the XS using<br>values for &theta; and &phi; from surrounding runs and found that the result was now consistent with<br>the neighboring momentum settings. He also played around with the acceptance cuts he<br>showed, and found a region using the "extreme cut" where the sawtooth pattern go away<br>and the yields become flat.<br />
<br />
<br />
==9/9/2015==<br />
<br />
Present: Min, JP, Jixie, Melissa <br><br />
By Phone: Vince, Jie, Chao, Ryan, Toby, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Jie<br />
**Gave an overview of his simulation study using SNAKE and MUDIFI. Using SNAKE, the<br>idea is to trace the particle trajectory in a series of free boxes, then an endplane can be<br>defined within the free boxes to determine the trajectory from endplane to endplane. In<br>g2psim this will be used to trace the trajectory between the sieve plane and the focal<br>plane. There are two important issues to consider, the magnetic field in the free boxes,<br>and the transportation method between the two endplanes. A Runge-Kutta method is <br>used for the transportation, and an adaptive method (which changes with field size and<br>gradient) is used to determine the step size. For the magnetic field, a 3D Tosca field<br>map is used for the septum, and an analytic model is used for the spectrometer magnets. <br> He also described the method for choosing the transportation function to determine the <br>25 matrix terms for each kinematic variable (up to 4th order). JP asked how to determine <br>which order is more important, and cautioned to be careful not to over fit the data. He and<br>Jie will discuss this more offline. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_09_09_simulation_update/2015_09_09_Simulation%20update.pdf here].<br />
<br />
*Chao<br />
**Gave an optics status update. The current problem is that changes in the horizontal beam<br>position changes the dp reconstruction. This was fixed by applying a linear correction in<br>BPM-x and BPM-y to &theta;, &phi; and dp. Applying this correction made the data/simulation <br>agree, but it is still necessary to understand the correction. Using dp scan data with beam<br>position scan data still leaves an offset in &theta; and &phi;. He also tried two other methods to do<br>the calibration. Method 1 uses the central hole to determine a constant offset, uses the<br>horizontal beam position scan data to determine all the matrix elements related to y, and<br>uses dp scan runs to fit the additional matrix elements. Method 2 uses beam position<br>scan data to determine the matrix elements that are not related to x<sub>fp</sub>. Neither of these<br>methods works very well, even when the fitting order of the matrix elements are adjusted.<br>He will continue to check more fitting procedures. More details can be found in his slides <br>[http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150909/Chao_WeeklyMeeting_09092015.pdf here].<br />
<br />
*Pengjia<br />
**Gave an update on comparing asymmetries from data/models for the 2.2 GeV, 5T <br>longitudinal setting. He first radiated the Bosted model XS; he showed the break down of<br>the different radiative corrections including the elastic tail (internal and external) and the<br>radiative effects from inelastic scattering. He showed a comparison with Ryan's results<br>which had good agreement, though there is some deviation when he used different proton<br>form factors (provided by Moshe). In order to compare the asymmetry result with data, he<br>needs to do the radiative corrections for the polarized MAID model, which he will continue<br>to work on. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/09092015/asym_20150909.pdf here].<br />
<br />
<br />
==9/2/2015==<br />
<br />
Present: JP, Min, Kalyan, Melissa <br><br />
By Phone: Vince, Alex, Jie, Chao, Ryan, Toby, Ellie, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Gave an update on determining the correction to asymmetries for pion contamination. <br>Previously, she used the 2.2 GeV, 5T longitudinal setting as an example, for this time <br>she used the transverse configuration, as it has the largest pion contamination. She <br>modified her method for differentiating between electrons and pions; previously she <br>identified pions as events that do not trigger the Cherenkov, this time she used a cut <br>below the single photo electron peak to select pions. JP suggested using stricter cuts <br>for selecting pions when determining the pion asymmetry, to make sure it is a clean <br>sample. Although this setting has a large pion contamination, the number of pion<br> events that remain after lead glass cuts are applied is low, so the overall correction <br>is very small. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Pion/PionAsym_08_31.pdf here].<br />
<br />
*Min<br />
**Gave an update on acceptance tuning. She looked at results from the 1.7 GeV setting <br>and found that the height of the peaks is different between data and simulation for <br>different holes in the sieve slit. Looking at the &theta; vs &phi; distribution, she noticed on the<br>positive &theta; side there were fewer holes in simulation than in data, and on the negative <br> &theta; side there were more holes in simulation compared to data. She tried adjusting the<br>aperture cuts by changing the physical location of the Q1, Q2 and septum planes to <br>uncover events that were previously blocked. After the adjustment, the data/simulation <br>results agreed much better. She showed a similar procedure for a dilution run and was<br>able to see better agreement between data/simulation after the aperture adjustments <br>were made. JP/Vince suggested being cautious when adjusting the aperture cuts, as<br> the apertures should be well defined already. They suggested adjusting things that are<br> less well known first, such as the septum field. More details can be seen in her slides<br>[http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/09022015.pdf here].<br />
<br />
*Ryan<br />
**Working on generating physics quantities using models to eventually compare with data.<br>So far, he has incorporated the MAID2007 and Hall B models. He calculated the <br>hyperfine splitting quantities &Delta;1 and &Delta;2 using the Hall B EG1 model and compared them<br> to the results in C. Carlson's 2006 paper. His results agreed very well, he only saw a<br> small deviation for &Delta;2 in the lowest Q<sup>2</sup> range. To check that nothing strange was going <br> on in the low Q<sup>2</sup> range, he calculated &Delta;2 for various small ranges around zero, to ensure<br>that the integration method is well behaved. The Carlson paper also includes calculations <br>using the Simula model, he would like to do a check of this method as well, but is unsure <br>where to find the Simula model. Since he was able to reproduce the hyperfine splitting <br>result, he is confident in his calculation method; it should be straightforward to calculate <br>other spin structure function integrals. More details on his method can be found in his <br>slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_09215.pdf here].<br />
<br />
*Toby<br />
**Showed an update on his acceptance/scattering angle study. He applied cuts of varying<br>strictness on the reconstructed &theta; vs &phi; distribution at the target. He then calculated the <br>real scattering angle before/after scattering for each cut. Using these scattering angles <br> as inputs for the Bosted model he was able to calculate the XS and compare it to data.<br>He showed the comparison between data/Bosted model for each acceptance cut. He <br>hoped that the more extreme acceptance cuts on the data would flatten the yield <br>distribution, but it actually just enhanced the sawtooth pattern. JP questioned why the <br>Bosted prediction for one momentum bin (the green one) was so much lower than the<br> neighboring ones. Toby said the only input that goes into the model is the scattering angle,<br> so it must be considerably different for this momentum setting. He also commented that<br>the model prediction is scaled to match the data, so the scaling enhances the jump in<br>the model. More details on his acceptance cuts and method can be found in his slides<br>[http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/acceptance_scatangle.pdf here].<br />
<br />
<br />
==8/26/2015==<br />
<br />
Present: Jixie, Alex, Min, Kalyan, JP, Chao, Melissa <br><br />
By Phone: Vince, Jie, Ryan, Toby, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Chao<br />
**Gave an update on optics studies. Previously, he showed a comparison between optics data <br>and simulation where he cut on individual sieve holes. For this week, he included a cut on y <br>and dp that he didn't include previously. In the plot of &theta; vs y, JP pointed out that there were <br>additional tails on some sieve holes, Chao says these tails go away when the &phi; cut is <br>included. He showed a 2D plot of &theta; vs &phi;, along with the 1D projection of these variables. JP<br>commented that the data is more smeared out than the simulation, so it is difficult to compare <br>data with simulation results. It's possible that some of the smearing comes from events that <br>punch through the sieve slit and are not being cut out (the simulation currently assumes these <br>events are stopped by the sieve). Looking at the center hole, the data/simulation agree <br>reasonably well, but the agreement gets worse for holes on the edge of the sieve slit. Chao<br>will continue to look into this. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150826/Chao_WeeklyMeeting_08262015.pdf here].<br />
**He also mentioned that ~1 month ago he reported a problem with the [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150708/Chao_WeeklyMeeting_07082015.pdf BPM simulation].<br>He found it was actually a problem with the simulation itself, which has now been updated <br> to correct the problem.<br />
<br />
<br />
'''General Discussion:'''<br />
*Pengjia has submitted his BPM NIM paper.<br />
<br />
<br />
==8/19/2015==<br />
<br />
Present: Chao, Jie, Min, Jixie, Kalyan, Melissa <br><br />
By Phone: Vince, Ryan, Toby, Karl, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Showed a method for determining the correction to asymmetries for pion contamination. The <br>measured asymmetry can be written in terms of the electron and pion asymmetries, multiplied <br>by the fraction of events of that particle. To differentiate between electrons and pions, a cut is<br>made on events that trigger the Cherenkov detector (electrons) and events that do not trigger<br>the Cherenkov (pions). Kalyan commented that this method of selecting pions may be too blind,<br> and suggested making a 2D cut on E/p vs Cherenkov instead. To determine the fraction of<br>electrons/pions, "good event" cuts are applied (loose acceptance cuts, single track events and<br>pion rejector cuts) and the number of electrons/pions that survive the cuts are counted. Although<br>the pion asymmetry is much larger than the electron asymmetry, the number of residual pions<br>is very small, so the overall correction is small. For this example the 2.2 GeV, 5T longitudinal<br>setting was used, but the correction may be larger for the 5T transverse settings, which she <br>will do next. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Pion/PionAsym_08_19.pdf here].<br />
<br />
*Min <br />
**Gave an update on acceptance studies. She used the 1.7 GeV, 2.5T setting (with 3rd septum <br>configuration) to test the acceptance cuts using the yield ratio of data to simulation. She <br>showed a plot of target &theta; vs &phi; for both data and simulation, and applied a graphical cut to get<br>rid of events on the edges. Looking at the resulting 1D plots shows reasonable agreement<br>between &theta; and &phi;. Vince pointed out that there seems to be some additional structure in the<br>dp distribution, and suggested expanding the &delta; cut out to &pm; 4% to see if there is more <br>hidden structure. Min said she has seen this in other settings as well and will look into it. She<br>also tried adjusting the cuts on &theta;, &phi; and &delta; and looked at how the ratio of yields from data/<br>simulation changed; the ratio starts to drop off as the cuts get wider. Next she will work on<br>calculating the yields using W bins. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/08192015.pdf here].<br />
<br />
<br />
==8/12/2015==<br />
<br />
Present: Jie, Chao, Kalyan, Min, Jixie, Melissa <br><br />
By Phone: Pengjia, Ryan, Toby, Karl, Ellie, Alex <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Chao<br />
**Gave an update on optics studies. Previously, Min has shown comparisons of data/simulation<br> where she looked at different columns of sieve holes. Chao continued this study by cutting on <br>individual sieve holes. Looking at the center sieve hole, the &phi; distribution looks reasonable, but <br>the &theta; distribution has some issues. Specifically, the data is wider on the left side (negative &theta;) <br>than the simulation. He showed results for several sieve holes, including one that was in the <br>row as the center hole, but in the farthest column on the left side of the sieve slit. In this case <br>the &theta; distribution had similar width for both data and simulation, but the height of the simulation<br> distribution was larger. This may suggest that something is wrong with the acceptance in the <br>simulation. The problem with &theta; seems to be systematic; for most of the sieve holes there are <br>more events on the left side of the data than in the simulation. Kalyan asked whether the <br>thickness of the sieve slit was taken into account, Chao says it was included in the simulation <br>and optimizer. Jixie suggested comparing the dp distributions for each sieve hole. More details <br>can be seen in Chao's slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150812/Chao_WeeklyMeeting_08122015.pdf here].<br />
<br />
<br />
==7/29/2015==<br />
<br />
Present: Chao, Min, JP, Melissa <br><br />
By Phone: Alex, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Min<br />
**Gave an update on acceptance studies. Previously, Chao showed a correction for the beam<br>position in g2psim. Min checked this correction by looking at optics runs. On the data she <br>applied a cut on dp (to select elastic events) and on the focal plane (to get rid of junk <br> events). On the simulation, only an aperture cut was applied. She compared the data and<br>simulation results for &theta; and &phi; both before and after drifting from the sieve slit to the target.<br>The effect of the target field on &theta; is not very large, though there is a shift down in angle.<br>However, the shape of the &theta; distribution is different between data and simulation. The<br>effect of the target field on &phi; is significant; it's not clear why this is the case. To try to<br>determine the reason for the discrepancies, she applied a cut along each column of sieve<br>slit holes in &phi; and compared the data and simulation results for &theta;,&phi; and dp. Column 2<br>seems to have the best agreement (for dp), columns 1 and 2 have a shift while columns<br>3-6 have a difference in width. Chao suggested also cutting along each row of sieve slit<br>holes to better study the effect of the drift on &phi;. Min will work on identifying the differences<br>between data and simulation, specifically whether the boundaries are different between<br>the two. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07272015/07292015.pdf here].<br />
<br />
<br />
==7/22/2015==<br />
<br />
Present: JP, Min, Jixie, Melissa <br><br />
By Phone: Alex, Ryan, Toby, Ellie, Karl, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Showed various checks for packing fraction runs that have large discrepancies, including <br>beam position, beam energy, spectrometer central momentum setting, septum current, and<br>the location of anneals. For both the 2.2 and 1.1 GeV settings, there are significant shifts in <br>the x and y beam position (2mm or more). She showed the average and standard deviation <br> of epics readings for the LHRS septum current for each run. For several runs, there are small <br>number of epics readings that drift from the average current. It's not clear if this is the <br>current is actually changing or if it is a readout problem. She will look into the yield vs time<br>to try to determine this. JP suggested making a raster cut on the center of the beam to get<br> rid of any potential scraping. Pengjia says there is a way to cut on raster size, but there will<br> be an additional BPM uncertainty. Melissa will discuss this more offline with Pengjia. More<br>details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_07_22.pdf here].<br />
<br />
*Pengjia<br />
**Gave an update on calculating asymmetries/cross sections using the MAID model. This time, <br>he used the Bosted model to get the unpolarized cross sections for the proton. Using unradiated <br>cross section models, he still saw a factor of 6 difference when compared with data. Ryan also <br>calculated asymmetries using unradiated models, and the results were consistent with Pengjia's, <br>so it seems the radiative effects contribute significantly to the factor of 6 difference. More <br>details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07222015/MAID_update_20150722.pdf here].<br />
<br />
<br />
==7/15/2015==<br />
<br />
Present: JP, Min, Chao, Jixie, Melissa <br><br />
By Phone: Ryan, Toby, Ellie, Karl, Vince, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Chao<br />
**Doing a check of simulation/data results for the 2.2 GeV, longitudinal setting in order <br>to check that the optics calibration matrix will work for all momentum settings (not <br>just elastic). He showed a comparison for several different momentum settings.<br> Vince suggested simulating more events, since the statistics start to drop off for <br>lower momentum settings. In general, the data is broader then the result from<br>simulation. In the &theta; distribution, the "tails" seen in the data are not symmetric. JP<br> suggested carefully selecting cuts to remove any background from the data to <br>ensure a good comparison with simulation. More details can be seen in his <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150715/Chao_WeeklyMeeting_07152015.pdf here].<br />
<br />
*Pengjia<br />
**More discussion on Pengjia's [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07082015/MAID_update_20150708.pdf slides] from last week. Pengjia has seen a factor of <br>six difference between his asymmetry calculated from data compared to the <br>asymmetry determined using the MAID model. Ryan did not see this factor of six <br>in his study, but in addition to using radiated XS models, he is using a combination <br>of the Bosted and MAID models (Pengjia is using just the MAID model). Karl <br>commented that the XS from MAID is not very good for our kinematics. Pengjia <br>also showed an estimated NH3 XS. JP commented that it was surprising that the <br>delta peak wasn't visible. Pengjia will look into this for next time.<br />
<br />
<br />
==7/8/2015==<br />
<br />
Present: JP, Min, Chao, Melissa <br><br />
By Phone: Toby, Vince <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Pengjia<br />
**Working on comparing asymmetries determined from MAID to those calculated from <br>data; last time he showed a factor of 6 difference between the two results. This <br>time, he showed two different methods for calculating the differential XS from the <br>virtual photon XS. The first method calculates the differential XS directly from <br>the virtual photon XS, and the second method calculates the differential XS using <br>F<sub>1</sub>, F<sub>2</sub>, g<sub>1</sub> and g<sub>2</sub>. He also showed two different methods for calculating the <br>asymmetry from the virtual photon XS; one method uses A<sub>1</sub> and A<sub>2</sub>, while the other <br>is calculated from the virtual photon XS. There was a discrepancy between the two <br>methods, but he found that there was actually a mistake in one of the equations. <br>While the results from the two methods agree with each other, they are still a factor <br>of 6 larger than the results from data. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07082015/MAID_update_20150708.pdf here].<br />
<br />
*Toby<br />
**Showed an update of his scattering angle study for model reconstruction. He is <br>using BPM and optics data to determine the scattering angle. He showed an example <br>of the calculated scattering angle; JP questioned whether the range was really from <br>0-16 deg. Toby pointed out that there really aren't many events at the boundaries, <br>the distribution is peaked between 4.5-9 deg. He then uses this scattering angle as<br>input for the Bosted model. At low &nu; the simulation results match reasonably well<br>with the data, but the discrepancy starts to become larger as &nu; increases. He took <br>a closer look at the reconstructed scattering angle for each central momentum, and <br>found that a second peak is visible for smaller values of p0. If this second peak was <br>real, the simulation should recreate the data, so this could suggest a problem with <br>the reconstruction. However, Chao pointed out that, for this energy setting, the optics <br>calibration is not complete (currently using the longitudinal optics matrix), so the <br>reconstructed &theta; and &phi; may not be correct yet. For next time, Toby will test this <br>analysis using the 1.7 GeV setting, which has calibrated optics. More details can <br> be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/scatangle_talk.pdf here].<br />
<br />
*Melissa<br />
**Gave a summary of packing fraction analysis. For some settings, the variation in the <br>yields (and P<sub>f</sub>) is due to a fluctuation in the beam position. This will hopefully be<br>resolved by Jie's beam position/acceptance study. For the 2.2 GeV, 2.5T transverse setting<br> there is also an issue of a shift in &nu; between runs. For the 1.1 GeV, 2.5T transverse <br>setting, the yields vary depending on the beam current used for each run. JP suggested <br>a few things to check as the possible cause for these discrepancies including drift in the <br>BCM calibration, anneals of the target material, drift in field (HRS or septum), etc. She <br>has posted a technote draft [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Technotes/PF_technote_draft.pdf here], feedback would be appreciated. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_07_08.pdf here].<br />
<br />
*Min<br />
**Gave an update on her acceptance study. Last time, she showed that the simulation results <br>are more narrow than the data. For this time, she tried cutting on just the center hole, <br>and found that the dp distribution from data better matched the simulation. JP suggested <br>cutting on each of the different holes individually to determine which hole causes the dp <br>distribution to be wider. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07082015/07062015.pdf here].<br />
<br />
*Chao<br />
**Gave an update on optics analysis, currently checking whether simulation results match <br>with data, starting with optics data. First he checked whether the geometry was correct, <br>some deviation was found in the recent optics meeting. The position of the BPMs is hard-<br>coded into the simulation, and the drifting algorithm is used to drift the electrons <br>backward to the BPMs to simulate the readout of BPM A and B. He compared the &theta; <br>distribution before drifting in the target field using a fixed and non-fixed BPM location. <br>The results using a fixed BPM match well with the data. He is currently working on <br>checking this for all momentum settings, and will follow up with Pengjia about the BPM <br>problem. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150708/Chao_WeeklyMeeting_07082015.pdf here].<br />
<br />
<br />
==7/1/2015==<br />
<br />
Present: Chao, Vince, Jie, JP, Min, Melissa <br><br />
By Phone: Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Min<br />
**Gave an update on acceptance studies. She showed a summary table of each energy <br>setting and septum configuration. There hasn't been any problems in the 2.2 GeV, 5T <br>longitudinal and 1.7 GeV, 2.5T transverse settings, but some settings (2.2 GeV, 2.5T <br> transverse, 1.2 GeV, 2.5T transverse and 2.2 GeV, 5T transverse) have a discrepancy <br>in the focal plane between data and simulation. She compared the data divided by the <br>Mott XS to the simulation results without XS, and found that the simulation results <br>of &theta; and &phi; are narrower then the data. JP commented that, while including the Mott<br>XS might change the shape of the distribution, it shouldn't change the boundary. She <br>work on figuring out the cause for this discrepancy before calculating the acceptance. <br>More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07012015/07012015.pdf here].<br />
<br />
*Pengjia<br />
**Comparing asymmetries determined from the MAID model to those calculated from data.<br>Last time he showed a factor of 6 difference between the two results. He determined the <br>scattering angle and Q<sup>2</sup> by fitting the data and compared them to the quantities calculated <br>from MAID. He also showed the results of calculating the quantities g<sub>1</sub>, g<sub>2</sub>, F<sub>1</sub>, F<sub>2</sub>, A<sub>L</sub>, A<sub>T</sub>,<br> dXS<sub>L</sub>, dXS<sub>T</sub>, XS<sub>tot</sub> andXS<sub>mott</sub> using MAID. He hasn't included radiative corrections in his <br>calculations, but this probably won't account for the factor of 6. More details can be seen <br>in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07012015/MAID_20150701.pdf here].<br />
<br />
<br />
----<br />
<br />
==Jan-June 2015==<br />
[[Minutes_Jan2015_to_June2015]]<br />
----<br />
<br />
==July-Dec 2014==<br />
[[Minutes_July2014_to_Dec2014]]<br />
----<br />
<br />
==Jan-June 2014==<br />
[[Minutes_Jan2014_to_June2014]]<br />
----<br />
<br />
==June-Dec 2013==<br />
[[Minutes_June2013_to_Dec2013]]<br />
----<br />
<br />
==Jan-May 2013==<br />
[[Minutes_Jan2013_to_May2013]]<br />
----<br />
<br />
==April-Dec 2012==<br />
[[Minutes_Apr2012_to_Dec2012]]<br />
----<br />
<br />
==Jan-March 2012==<br />
[[Minutes_Jan2012_to_Mar2012]]<br />
----<br />
==July-Dec 2011==<br />
[[Minutes_July2011_to_Dec_2011]]<br />
----<br />
==Jan-June 2011==<br />
[[Minutes_Jan2011_to_June_2011]]<br />
----</div>Melissachttps://hallaweb.jlab.org/wiki/index.php?title=G2p_Analysis_Minutes&diff=26329G2p Analysis Minutes2015-11-18T14:27:01Z<p>Melissac: /* 10/28/2015 */</p>
<hr />
<div>Minutes of the weekly analysis meetings<br />
----<br />
[https://hallaweb.jlab.org/wiki/index.php/G2p_Weekly_Analysis Agenda]<br />
<br />
==11/4/2015==<br />
<br />
Present: Min, Jixie, Melissa <br><br />
By Phone: Chao, Vince, Toby, Ryan, Alex, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Ryan<br />
**Gave an overview of g2p elastic tail and angle reconstruction. The elastic tail is highly sensitive<br>to the scattering angle, so his goal is to develop a method to include these variations in the elastic <br>tail subtraction. He started by looking at the simplest case, helium dilution runs. Using his method, <br>he looked at the elastic tail across a series of different momentum settings, andfound that the tail <br>was not continuous, which he assumed was due to variations in the scattering angle. He did a pseudo-<br>simulation using the Bosted model and varying the scattering angle to confirm the "jump" seen in the <br>elastic tail. However, when he looked at the normalized yields for this same data, he did not see the <br>same discontinuity. This suggests there might be a problem with the scattering angle reconstruction. <br>Chao mentioned that the reconstruction code has been updated (at least for the longitudinal setting) <br>the last replay; he will provide this code to Toby so he can do another replay. Details of the method <br>and cuts used can be seen in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_11415.pdf here].<br />
<br />
*Jie<br />
**Gave an update on his simulation study to understand the beam dependence on the yields. He used the <br>beam position and raster size as input to g2psim, and included radiative and acceptance effects. In <br>general, he found there is a much larger dependence on the beam position using a rastered beam <br>compared to a point beam. He summarized his results for various different momentum settings and found <br>that, in some cases, his results matched what we saw in the data, but not in all cases. Vince suggested <br>testing how much the beam position would need to be changed (for a given momentum setting) to match <br>the simulation with the data. The details of his study can be found in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/yields_update_2015_11_04.pdf here], he is also compiling <br>a technote on this analysis. <br />
<br />
<br />
==10/28/2015==<br />
<br />
Present: JP, Min, Kalyan, Melissa <br><br />
By Phone: Alexandre, Vince, Jie, Ryan, Toby, Ellie, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Gave an overview of contributions to the systematic uncertainty for the asymmetry. There are <br>several contributions which are very small (<0.1%) including the charge asymmetry, livetime <br>asymmetry and pion contamination. The target polarization uncertainty was surprisingly small.<br>The values currently listed in the mysql DB for this quantity appear to be incorrect; Toby will<br>update these values. For the contribution from the dilution factor and radiative corrections, she<br> assigned 5% as a placeholder until a better estimate could be made. Karl/Ryan commented <br>that 5% uncertainty on the radiative corrections may be too small, 10-15% would be a better<br>estimate at this point. The tables shown for the longitudinal and transverse settings represent<br>an overestimate of the uncertainty; in the long-term this could be looked at more carefully to<br>decrease the overall systematic uncertainty. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Asym/Asym_10_28.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*There has been a request from the Hall A CC to have an update on g2p at the winter collaboration <br>meeting. Ellie and Jie are both interested, they will check the dates of the meetings to see if they <br>are available.<br />
<br />
==10/14/2015==<br />
<br />
Present: JP, Min, Jixie, Kalyan, Melissa <br><br />
By Phone: Alexandre, Vince, Jie, Todd, Haiyan, Pengjia, Karl, Toby, Ryan, Xiaochao, Nilanga, Chao <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Karl<br />
**Went over the goals of the collaboration meeting:<br />
***Discuss physics topics for students graduating soon<br />
***Identify major remaining physics topics<br />
***Establish a policy for the release of plots<br />
**Suggested a policy for collaboration release of physics results, including specific requirements <br>for moving from "very preliminary" to "preliminary" to "final" results. Details can be seen in his <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/slifer/2015/slifer_g2pcollab_101415.pdf here], and they will be circulated to the g2p mailing list with some small modifications.<br />
<br />
*Pengjia<br />
**Will be defending next Wednesday (Oct. 21st). He showed a "very preliminary" physics <br> asymmetry for the 2.2 GeV 5T setting (both longitudinal and transverse) with a comparison to <br> a radiated model prediction. He used this result to extract a preliminary value for g1 and g2,<br>using the Bosted model as input for the cross section. This result does not include radiative<br>corrections. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/graduate_2015.pdf here].<br />
<br />
*Min<br />
**Showed an overview of status of acceptance study; the overall goal is to match the simulation<br>results to the data, so that the simulation can be used to calculate the acceptance. She<br>described the various attempts to correct the simulation results to match the data. Adjusting the<br> apertures based on optics data works well, but the other two methods (adjusting the apertures <br>based on dilution data and adjusting the acceptance cuts after removing the Mott XS from the <br>data) only work well around the target run. In addition, the simulated yield has a different shape <br>than the data, so the simulation must be adjusted to match this. She will go through this process <br>again once Chao is finished with the optics correction. She is planning to graduate next January, <br>and would like to include a cross section difference for one kinematic setting in her thesis. More <br>details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/collab/10142015_collab_Min.pdf here].<br />
<br />
*Melissa<br />
**Gave an overview of packing fraction analysis. Of the 5 total settings there are 3 that are reasonably <br>stable with some small drifts in yields, and 2 settings that have larger problems. During the 2.2 GeV, <br>2.5T setting the raster size was changed, which could possibly be corrected by applying a cut on<br>the center of the raster. The 1.1 GeV setting has large variations in the elastic yields; some of these <br>runs were taken at low currents (8-20nA), so the beam position information is not reliable. She also <br>showed the results of a pion asymmetry study. Although the pion asymmetry is very large, the <br>residual pion contamination after PID cuts are applied is very small, so the correction is not large. <br>She has scheduled her defense for December 4th, and would like to include a preliminary result <br>for g1,g2 in her thesis. To include a fully corrected result she will need preliminary radiative <br>corrections and dilution results, which she will work with Ryan and Toby to get. More details can <br>be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/talks/MCummings_CollabMeeting_20151013.pdf here].<br />
<br />
*Toby<br />
**Showed a preliminary dilution value that he had shown previously, and described several issues <br>with the result. These issues include that the model assumes a constant scattering angle, and does <br>not include some acceptance effects that are seen in the data. He has been working on correcting <br>these issues by incorporating a scattering angle from data into the model and applying acceptance <br>cuts to the data to remove acceptance effects. He showed the result of applying the acceptance cut <br>across all kinematics for the 5T longitudinal setting; including the acceptance cut gets rid of some of <br>the strange structure seen in the yields, such as the sawtooth pattern seen at high nu. The downside <br>of this method is that the acceptance cut causes a large loss in statistics. He is currently working on <br>trying to re-incorporate some of the lost statistics from the acceptance cut. More details can be seen <br>in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/collaborationupdate.pdf here].<br />
<br />
*Jie<br />
**Gave an update on his study using simulation to understand the drifts in yields. He looked at several <br>momentum settings in the 2.2 GeV, 2.5T setting that had variation in the yields. He varied the beam <br>position along the horizontal and vertical directions using both a point beam and rastered beam. He <br>generated a table summarizing the results using a Monte Carlo method, cross checking with averaged <br>acceptance. His results were similar to his previous test using only the Bosted model; some results <br>agree with what was seen in the data, some have the opposite sign. He will write up his method and <br>results in a technote. He is planning to graduate in summer of 2016. More details can be seen in his <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_10_09_simulation/2015_10_14_collaboration_meeting.pdf here].<br />
<br />
*Chao<br />
**Gave an update on optics analysis. Comparisons of simulation with data revealed that the <br>reconstructed kinematics have some offset. A correction was added to the reconstructed kinematics <br>(vs beam position) and he is currently working on merging this correction into the database with a <br>finely tuned fitting procedure. The problem is that the horizontal beam position shifts the dp <br>reconstruction. He showed the results of applying the new optics matrix which corrects for this shift. <br> He will apply this method to all kinematic settings and study the uncertainty of the optics. Once this <br>is done he will write a NIM paper for g2p optics. He plans to graduate in February/March and would <br>like to include the cross section difference for one or two settings with tuned acceptance and model <br>inputs to obtain a physics result. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20151014/Chao_WeeklyMeeting_10142015.pdf here].<br />
<br />
*Ryan<br />
**Since the last collaboration meeting he has improved the model tuning procedure by using an <br>automated procedure instead of tuning the model by hand. He has tested this using carbon data <br>from the UVa database and will run it for nitrogen data once he has updated saGDH N2 cross <br>sections from Vince. He also updated the systematic error study for inelastic unpolarized radiative <br>corrections by separating the integration/iteration error from the interpolation error. He has the <br>polarized radiative correction code running, and has completed a systematic uncertainty study on <br>the inelastic radiative corrections. He is also working on evaluating physics quantities using models, <br>specifically the hyperfine splitting calculation. He plans to graduate in summer/fall of 2016 and would <br>like to include full radiative corrections on g2p polarized cross sections in his thesis. More details can<br> be seen in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_101315.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*Important to do cross checks of results between students (ex. asymmetries)<br />
*Must be careful to include details of any physics results (whether radiative corrections are included,<br>dilution factor, model input instead of data, etc.)<br />
<br />
==9/30/2015==<br />
<br />
Present: JP, Kalyan, Jixie, Min <br><br />
By Phone: Pengjia, Toby, Ryan, Vince, Jie, Chao, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Toby<br />
**Showed an update on his acceptance/dilution study. He continued with the study of the cuts on the <br>reconstructed &theta; vs &phi; distribution at the target. He scanned several different &theta; vs &phi; cuts to see how <br>the acceptance effects the scattering angle and resulting yields. It turns out the small angle region is <br>influenced by the acceptance a lot but the center region gives a good agreement to the model. He <br>also loosed the center cut to &theta; ~ ± 40 mrad and &phi; ~ ± 10 mrad, the data still agreed with the model. <br>He then recalculated the dilution factor for 2.254 GeV longitudinal setting. More details on his <br>acceptance cuts and method can be found in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/diltalk_093015.pdf here].<br />
<br />
<br />
==9/23/2015==<br />
<br />
Present: JP, Kalyan, Min, Melissa <br><br />
By Phone: Pengjia, Toby, Ryan, Vince, Jie, Chao, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Pengjia<br />
**Showed the structure of his code to create a radiated model of the MAID and Bosted <br>models, based on Ryan's radiative correction work. He showed the breakdown of the <br>different components to the radiated model (internal, external and elastic tail). He used<br> the radiated model to calculate an asymmetry and cross section differences, which he <br> compared with data. Finally, he combined asymmetries calculated from data with the <br>Bosted model cross section to calculate a value for g1 and g2, which he compared <br>with values of g1/g2 determined using the MAID model. More details can be seen in <br>his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/09222015/asym_g12.pdf here].<br />
<br />
*Min<br />
**Gave an update on acceptance studies. Last time, she found that by adjusting the<br>apertures in the simulation she could match the data/simulation results for dp (for one <br>momentum setting). She tested this method for other momentum settings and found <br>that it did not work as well. She also showed a comparison of the yield spectrum for<br>helium runs in the 1.7 GeV setting; the shape of the two distributions are quite <br>different, which might suggest that the model deviates significantly form the data. In<br>the simulated results she saw several "bumps" in the yield, which correspond to the<br>location of resonances. She will update these results when the optics corrections are <br>complete. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/09232015.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*We would like to schedule another collaboration meeting in the near future. The <br>meeting is tentatively scheduled for Wednesday October 14th during our usual meeting <br>time (10am-12pm).<br />
*The purpose of the meeting is to:<br />
**Discuss student thesis topics (particularly any updates from the last <br>collaboration meeting)<br />
**Establish a procedure for presentation/release of collaboration plots/results<br />
*Each student should prepare a few slides (~5 minutes) to show analysis progress<br />
<br />
<br />
==9/16/2015==<br />
<br />
Present: Min, JP, Jixie, Melissa <br><br />
By Phone: Vince, Jie, Chao, Pengjia, Alex, Ryan, Toby, Ellie <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Jie<br />
**Gave an update on his simulation study using MUDIFI. Last time he showed that he uses a<br>least square fit to go from endplane to endplane. For the g2p simulation, it's used to go from<br>(x,y,&theta;,&phi;,dp) in the target plane to (x,y,&theta;,&phi;,dp) in the focal plane. SNAKE produces (x,y,&theta;,&phi;,dp)<br>data in both planes and a polynomial function can be used to determine the relationship<br>between the two planes. First the maximum power for each variable is determined, symmetries<br>are included (if applicable), then the priority of each function must be determined. A Gram-<br>Schmidt transformation is used to do the minimization, and the final step is to decide whether<br>to accept the function f<sub>i</sub>. JP/Vince asked how the priority for each function is chosen, since the<br>choice could introduce some ordering dependence. Since we don't have enough data to<br>constrain, JP suggested introducing some physics. He also suggested getting rid of dp in the<br>focal plane (since it is really just dp in the target plane) so that there is one less dimension to<br>fit. More details can be seen in Jie's slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_09_15_simulation/2015_09_15_Simulation_update.pdf here].<br />
<br />
*Ryan<br />
**Gave an update on evaluating physics quantities using models. His goal was to do a<br>comparison of the hyperfine splitting calculation in C. Carlson's 2006/2008 paper using MAID<br>and Hall B models. Previously he showed a comparison using the Hall B model, where he saw<br>good agreement between his calculation and Carlson's result. For this time he also did a<br>comparison using the MAID model. There is a large difference between the two models for the<br>value of the integrand of &Delta;<sub>2</sub>, over the full range of Q<sup>2</sup>. JP suggested comparing the value of g2<br>between the two models, instead of &Delta;<sub>2</sub>. More details can be seen in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_091615.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*Toby<br />
**Last time he showed a comparison between data and cross sections calculated using the<br>Bosted model (seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/acceptance_scatangle.pdf here]). The model was not continuous for one momentum setting. It <br>turns out the BPM was not recording for that setting, so he re-calculated the XS using<br>values for &theta; and &phi; from surrounding runs and found that the result was now consistent with<br>the neighboring momentum settings. He also played around with the acceptance cuts he<br>showed, and found a region using the "extreme cut" where the sawtooth pattern go away<br>and the yields become flat.<br />
<br />
<br />
==9/9/2015==<br />
<br />
Present: Min, JP, Jixie, Melissa <br><br />
By Phone: Vince, Jie, Chao, Ryan, Toby, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Jie<br />
**Gave an overview of his simulation study using SNAKE and MUDIFI. Using SNAKE, the<br>idea is to trace the particle trajectory in a series of free boxes, then an endplane can be<br>defined within the free boxes to determine the trajectory from endplane to endplane. In<br>g2psim this will be used to trace the trajectory between the sieve plane and the focal<br>plane. There are two important issues to consider, the magnetic field in the free boxes,<br>and the transportation method between the two endplanes. A Runge-Kutta method is <br>used for the transportation, and an adaptive method (which changes with field size and<br>gradient) is used to determine the step size. For the magnetic field, a 3D Tosca field<br>map is used for the septum, and an analytic model is used for the spectrometer magnets. <br> He also described the method for choosing the transportation function to determine the <br>25 matrix terms for each kinematic variable (up to 4th order). JP asked how to determine <br>which order is more important, and cautioned to be careful not to over fit the data. He and<br>Jie will discuss this more offline. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_09_09_simulation_update/2015_09_09_Simulation%20update.pdf here].<br />
<br />
*Chao<br />
**Gave an optics status update. The current problem is that changes in the horizontal beam<br>position changes the dp reconstruction. This was fixed by applying a linear correction in<br>BPM-x and BPM-y to &theta;, &phi; and dp. Applying this correction made the data/simulation <br>agree, but it is still necessary to understand the correction. Using dp scan data with beam<br>position scan data still leaves an offset in &theta; and &phi;. He also tried two other methods to do<br>the calibration. Method 1 uses the central hole to determine a constant offset, uses the<br>horizontal beam position scan data to determine all the matrix elements related to y, and<br>uses dp scan runs to fit the additional matrix elements. Method 2 uses beam position<br>scan data to determine the matrix elements that are not related to x<sub>fp</sub>. Neither of these<br>methods works very well, even when the fitting order of the matrix elements are adjusted.<br>He will continue to check more fitting procedures. More details can be found in his slides <br>[http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150909/Chao_WeeklyMeeting_09092015.pdf here].<br />
<br />
*Pengjia<br />
**Gave an update on comparing asymmetries from data/models for the 2.2 GeV, 5T <br>longitudinal setting. He first radiated the Bosted model XS; he showed the break down of<br>the different radiative corrections including the elastic tail (internal and external) and the<br>radiative effects from inelastic scattering. He showed a comparison with Ryan's results<br>which had good agreement, though there is some deviation when he used different proton<br>form factors (provided by Moshe). In order to compare the asymmetry result with data, he<br>needs to do the radiative corrections for the polarized MAID model, which he will continue<br>to work on. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/09092015/asym_20150909.pdf here].<br />
<br />
<br />
==9/2/2015==<br />
<br />
Present: JP, Min, Kalyan, Melissa <br><br />
By Phone: Vince, Alex, Jie, Chao, Ryan, Toby, Ellie, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Gave an update on determining the correction to asymmetries for pion contamination. <br>Previously, she used the 2.2 GeV, 5T longitudinal setting as an example, for this time <br>she used the transverse configuration, as it has the largest pion contamination. She <br>modified her method for differentiating between electrons and pions; previously she <br>identified pions as events that do not trigger the Cherenkov, this time she used a cut <br>below the single photo electron peak to select pions. JP suggested using stricter cuts <br>for selecting pions when determining the pion asymmetry, to make sure it is a clean <br>sample. Although this setting has a large pion contamination, the number of pion<br> events that remain after lead glass cuts are applied is low, so the overall correction <br>is very small. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Pion/PionAsym_08_31.pdf here].<br />
<br />
*Min<br />
**Gave an update on acceptance tuning. She looked at results from the 1.7 GeV setting <br>and found that the height of the peaks is different between data and simulation for <br>different holes in the sieve slit. Looking at the &theta; vs &phi; distribution, she noticed on the<br>positive &theta; side there were fewer holes in simulation than in data, and on the negative <br> &theta; side there were more holes in simulation compared to data. She tried adjusting the<br>aperture cuts by changing the physical location of the Q1, Q2 and septum planes to <br>uncover events that were previously blocked. After the adjustment, the data/simulation <br>results agreed much better. She showed a similar procedure for a dilution run and was<br>able to see better agreement between data/simulation after the aperture adjustments <br>were made. JP/Vince suggested being cautious when adjusting the aperture cuts, as<br> the apertures should be well defined already. They suggested adjusting things that are<br> less well known first, such as the septum field. More details can be seen in her slides<br>[http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/09022015.pdf here].<br />
<br />
*Ryan<br />
**Working on generating physics quantities using models to eventually compare with data.<br>So far, he has incorporated the MAID2007 and Hall B models. He calculated the <br>hyperfine splitting quantities &Delta;1 and &Delta;2 using the Hall B EG1 model and compared them<br> to the results in C. Carlson's 2006 paper. His results agreed very well, he only saw a<br> small deviation for &Delta;2 in the lowest Q<sup>2</sup> range. To check that nothing strange was going <br> on in the low Q<sup>2</sup> range, he calculated &Delta;2 for various small ranges around zero, to ensure<br>that the integration method is well behaved. The Carlson paper also includes calculations <br>using the Simula model, he would like to do a check of this method as well, but is unsure <br>where to find the Simula model. Since he was able to reproduce the hyperfine splitting <br>result, he is confident in his calculation method; it should be straightforward to calculate <br>other spin structure function integrals. More details on his method can be found in his <br>slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_09215.pdf here].<br />
<br />
*Toby<br />
**Showed an update on his acceptance/scattering angle study. He applied cuts of varying<br>strictness on the reconstructed &theta; vs &phi; distribution at the target. He then calculated the <br>real scattering angle before/after scattering for each cut. Using these scattering angles <br> as inputs for the Bosted model he was able to calculate the XS and compare it to data.<br>He showed the comparison between data/Bosted model for each acceptance cut. He <br>hoped that the more extreme acceptance cuts on the data would flatten the yield <br>distribution, but it actually just enhanced the sawtooth pattern. JP questioned why the <br>Bosted prediction for one momentum bin (the green one) was so much lower than the<br> neighboring ones. Toby said the only input that goes into the model is the scattering angle,<br> so it must be considerably different for this momentum setting. He also commented that<br>the model prediction is scaled to match the data, so the scaling enhances the jump in<br>the model. More details on his acceptance cuts and method can be found in his slides<br>[http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/acceptance_scatangle.pdf here].<br />
<br />
<br />
==8/26/2015==<br />
<br />
Present: Jixie, Alex, Min, Kalyan, JP, Chao, Melissa <br><br />
By Phone: Vince, Jie, Ryan, Toby, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Chao<br />
**Gave an update on optics studies. Previously, he showed a comparison between optics data <br>and simulation where he cut on individual sieve holes. For this week, he included a cut on y <br>and dp that he didn't include previously. In the plot of &theta; vs y, JP pointed out that there were <br>additional tails on some sieve holes, Chao says these tails go away when the &phi; cut is <br>included. He showed a 2D plot of &theta; vs &phi;, along with the 1D projection of these variables. JP<br>commented that the data is more smeared out than the simulation, so it is difficult to compare <br>data with simulation results. It's possible that some of the smearing comes from events that <br>punch through the sieve slit and are not being cut out (the simulation currently assumes these <br>events are stopped by the sieve). Looking at the center hole, the data/simulation agree <br>reasonably well, but the agreement gets worse for holes on the edge of the sieve slit. Chao<br>will continue to look into this. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150826/Chao_WeeklyMeeting_08262015.pdf here].<br />
**He also mentioned that ~1 month ago he reported a problem with the [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150708/Chao_WeeklyMeeting_07082015.pdf BPM simulation].<br>He found it was actually a problem with the simulation itself, which has now been updated <br> to correct the problem.<br />
<br />
<br />
'''General Discussion:'''<br />
*Pengjia has submitted his BPM NIM paper.<br />
<br />
<br />
==8/19/2015==<br />
<br />
Present: Chao, Jie, Min, Jixie, Kalyan, Melissa <br><br />
By Phone: Vince, Ryan, Toby, Karl, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Showed a method for determining the correction to asymmetries for pion contamination. The <br>measured asymmetry can be written in terms of the electron and pion asymmetries, multiplied <br>by the fraction of events of that particle. To differentiate between electrons and pions, a cut is<br>made on events that trigger the Cherenkov detector (electrons) and events that do not trigger<br>the Cherenkov (pions). Kalyan commented that this method of selecting pions may be too blind,<br> and suggested making a 2D cut on E/p vs Cherenkov instead. To determine the fraction of<br>electrons/pions, "good event" cuts are applied (loose acceptance cuts, single track events and<br>pion rejector cuts) and the number of electrons/pions that survive the cuts are counted. Although<br>the pion asymmetry is much larger than the electron asymmetry, the number of residual pions<br>is very small, so the overall correction is small. For this example the 2.2 GeV, 5T longitudinal<br>setting was used, but the correction may be larger for the 5T transverse settings, which she <br>will do next. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Pion/PionAsym_08_19.pdf here].<br />
<br />
*Min <br />
**Gave an update on acceptance studies. She used the 1.7 GeV, 2.5T setting (with 3rd septum <br>configuration) to test the acceptance cuts using the yield ratio of data to simulation. She <br>showed a plot of target &theta; vs &phi; for both data and simulation, and applied a graphical cut to get<br>rid of events on the edges. Looking at the resulting 1D plots shows reasonable agreement<br>between &theta; and &phi;. Vince pointed out that there seems to be some additional structure in the<br>dp distribution, and suggested expanding the &delta; cut out to &pm; 4% to see if there is more <br>hidden structure. Min said she has seen this in other settings as well and will look into it. She<br>also tried adjusting the cuts on &theta;, &phi; and &delta; and looked at how the ratio of yields from data/<br>simulation changed; the ratio starts to drop off as the cuts get wider. Next she will work on<br>calculating the yields using W bins. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/08192015.pdf here].<br />
<br />
<br />
==8/12/2015==<br />
<br />
Present: Jie, Chao, Kalyan, Min, Jixie, Melissa <br><br />
By Phone: Pengjia, Ryan, Toby, Karl, Ellie, Alex <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Chao<br />
**Gave an update on optics studies. Previously, Min has shown comparisons of data/simulation<br> where she looked at different columns of sieve holes. Chao continued this study by cutting on <br>individual sieve holes. Looking at the center sieve hole, the &phi; distribution looks reasonable, but <br>the &theta; distribution has some issues. Specifically, the data is wider on the left side (negative &theta;) <br>than the simulation. He showed results for several sieve holes, including one that was in the <br>row as the center hole, but in the farthest column on the left side of the sieve slit. In this case <br>the &theta; distribution had similar width for both data and simulation, but the height of the simulation<br> distribution was larger. This may suggest that something is wrong with the acceptance in the <br>simulation. The problem with &theta; seems to be systematic; for most of the sieve holes there are <br>more events on the left side of the data than in the simulation. Kalyan asked whether the <br>thickness of the sieve slit was taken into account, Chao says it was included in the simulation <br>and optimizer. Jixie suggested comparing the dp distributions for each sieve hole. More details <br>can be seen in Chao's slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150812/Chao_WeeklyMeeting_08122015.pdf here].<br />
<br />
<br />
==7/29/2015==<br />
<br />
Present: Chao, Min, JP, Melissa <br><br />
By Phone: Alex, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Min<br />
**Gave an update on acceptance studies. Previously, Chao showed a correction for the beam<br>position in g2psim. Min checked this correction by looking at optics runs. On the data she <br>applied a cut on dp (to select elastic events) and on the focal plane (to get rid of junk <br> events). On the simulation, only an aperture cut was applied. She compared the data and<br>simulation results for &theta; and &phi; both before and after drifting from the sieve slit to the target.<br>The effect of the target field on &theta; is not very large, though there is a shift down in angle.<br>However, the shape of the &theta; distribution is different between data and simulation. The<br>effect of the target field on &phi; is significant; it's not clear why this is the case. To try to<br>determine the reason for the discrepancies, she applied a cut along each column of sieve<br>slit holes in &phi; and compared the data and simulation results for &theta;,&phi; and dp. Column 2<br>seems to have the best agreement (for dp), columns 1 and 2 have a shift while columns<br>3-6 have a difference in width. Chao suggested also cutting along each row of sieve slit<br>holes to better study the effect of the drift on &phi;. Min will work on identifying the differences<br>between data and simulation, specifically whether the boundaries are different between<br>the two. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07272015/07292015.pdf here].<br />
<br />
<br />
==7/22/2015==<br />
<br />
Present: JP, Min, Jixie, Melissa <br><br />
By Phone: Alex, Ryan, Toby, Ellie, Karl, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Showed various checks for packing fraction runs that have large discrepancies, including <br>beam position, beam energy, spectrometer central momentum setting, septum current, and<br>the location of anneals. For both the 2.2 and 1.1 GeV settings, there are significant shifts in <br>the x and y beam position (2mm or more). She showed the average and standard deviation <br> of epics readings for the LHRS septum current for each run. For several runs, there are small <br>number of epics readings that drift from the average current. It's not clear if this is the <br>current is actually changing or if it is a readout problem. She will look into the yield vs time<br>to try to determine this. JP suggested making a raster cut on the center of the beam to get<br> rid of any potential scraping. Pengjia says there is a way to cut on raster size, but there will<br> be an additional BPM uncertainty. Melissa will discuss this more offline with Pengjia. More<br>details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_07_22.pdf here].<br />
<br />
*Pengjia<br />
**Gave an update on calculating asymmetries/cross sections using the MAID model. This time, <br>he used the Bosted model to get the unpolarized cross sections for the proton. Using unradiated <br>cross section models, he still saw a factor of 6 difference when compared with data. Ryan also <br>calculated asymmetries using unradiated models, and the results were consistent with Pengjia's, <br>so it seems the radiative effects contribute significantly to the factor of 6 difference. More <br>details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07222015/MAID_update_20150722.pdf here].<br />
<br />
<br />
==7/15/2015==<br />
<br />
Present: JP, Min, Chao, Jixie, Melissa <br><br />
By Phone: Ryan, Toby, Ellie, Karl, Vince, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Chao<br />
**Doing a check of simulation/data results for the 2.2 GeV, longitudinal setting in order <br>to check that the optics calibration matrix will work for all momentum settings (not <br>just elastic). He showed a comparison for several different momentum settings.<br> Vince suggested simulating more events, since the statistics start to drop off for <br>lower momentum settings. In general, the data is broader then the result from<br>simulation. In the &theta; distribution, the "tails" seen in the data are not symmetric. JP<br> suggested carefully selecting cuts to remove any background from the data to <br>ensure a good comparison with simulation. More details can be seen in his <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150715/Chao_WeeklyMeeting_07152015.pdf here].<br />
<br />
*Pengjia<br />
**More discussion on Pengjia's [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07082015/MAID_update_20150708.pdf slides] from last week. Pengjia has seen a factor of <br>six difference between his asymmetry calculated from data compared to the <br>asymmetry determined using the MAID model. Ryan did not see this factor of six <br>in his study, but in addition to using radiated XS models, he is using a combination <br>of the Bosted and MAID models (Pengjia is using just the MAID model). Karl <br>commented that the XS from MAID is not very good for our kinematics. Pengjia <br>also showed an estimated NH3 XS. JP commented that it was surprising that the <br>delta peak wasn't visible. Pengjia will look into this for next time.<br />
<br />
<br />
==7/8/2015==<br />
<br />
Present: JP, Min, Chao, Melissa <br><br />
By Phone: Toby, Vince <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Pengjia<br />
**Working on comparing asymmetries determined from MAID to those calculated from <br>data; last time he showed a factor of 6 difference between the two results. This <br>time, he showed two different methods for calculating the differential XS from the <br>virtual photon XS. The first method calculates the differential XS directly from <br>the virtual photon XS, and the second method calculates the differential XS using <br>F<sub>1</sub>, F<sub>2</sub>, g<sub>1</sub> and g<sub>2</sub>. He also showed two different methods for calculating the <br>asymmetry from the virtual photon XS; one method uses A<sub>1</sub> and A<sub>2</sub>, while the other <br>is calculated from the virtual photon XS. There was a discrepancy between the two <br>methods, but he found that there was actually a mistake in one of the equations. <br>While the results from the two methods agree with each other, they are still a factor <br>of 6 larger than the results from data. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07082015/MAID_update_20150708.pdf here].<br />
<br />
*Toby<br />
**Showed an update of his scattering angle study for model reconstruction. He is <br>using BPM and optics data to determine the scattering angle. He showed an example <br>of the calculated scattering angle; JP questioned whether the range was really from <br>0-16 deg. Toby pointed out that there really aren't many events at the boundaries, <br>the distribution is peaked between 4.5-9 deg. He then uses this scattering angle as<br>input for the Bosted model. At low &nu; the simulation results match reasonably well<br>with the data, but the discrepancy starts to become larger as &nu; increases. He took <br>a closer look at the reconstructed scattering angle for each central momentum, and <br>found that a second peak is visible for smaller values of p0. If this second peak was <br>real, the simulation should recreate the data, so this could suggest a problem with <br>the reconstruction. However, Chao pointed out that, for this energy setting, the optics <br>calibration is not complete (currently using the longitudinal optics matrix), so the <br>reconstructed &theta; and &phi; may not be correct yet. For next time, Toby will test this <br>analysis using the 1.7 GeV setting, which has calibrated optics. More details can <br> be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/scatangle_talk.pdf here].<br />
<br />
*Melissa<br />
**Gave a summary of packing fraction analysis. For some settings, the variation in the <br>yields (and P<sub>f</sub>) is due to a fluctuation in the beam position. This will hopefully be<br>resolved by Jie's beam position/acceptance study. For the 2.2 GeV, 2.5T transverse setting<br> there is also an issue of a shift in &nu; between runs. For the 1.1 GeV, 2.5T transverse <br>setting, the yields vary depending on the beam current used for each run. JP suggested <br>a few things to check as the possible cause for these discrepancies including drift in the <br>BCM calibration, anneals of the target material, drift in field (HRS or septum), etc. She <br>has posted a technote draft [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Technotes/PF_technote_draft.pdf here], feedback would be appreciated. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_07_08.pdf here].<br />
<br />
*Min<br />
**Gave an update on her acceptance study. Last time, she showed that the simulation results <br>are more narrow than the data. For this time, she tried cutting on just the center hole, <br>and found that the dp distribution from data better matched the simulation. JP suggested <br>cutting on each of the different holes individually to determine which hole causes the dp <br>distribution to be wider. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07082015/07062015.pdf here].<br />
<br />
*Chao<br />
**Gave an update on optics analysis, currently checking whether simulation results match <br>with data, starting with optics data. First he checked whether the geometry was correct, <br>some deviation was found in the recent optics meeting. The position of the BPMs is hard-<br>coded into the simulation, and the drifting algorithm is used to drift the electrons <br>backward to the BPMs to simulate the readout of BPM A and B. He compared the &theta; <br>distribution before drifting in the target field using a fixed and non-fixed BPM location. <br>The results using a fixed BPM match well with the data. He is currently working on <br>checking this for all momentum settings, and will follow up with Pengjia about the BPM <br>problem. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150708/Chao_WeeklyMeeting_07082015.pdf here].<br />
<br />
<br />
==7/1/2015==<br />
<br />
Present: Chao, Vince, Jie, JP, Min, Melissa <br><br />
By Phone: Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Min<br />
**Gave an update on acceptance studies. She showed a summary table of each energy <br>setting and septum configuration. There hasn't been any problems in the 2.2 GeV, 5T <br>longitudinal and 1.7 GeV, 2.5T transverse settings, but some settings (2.2 GeV, 2.5T <br> transverse, 1.2 GeV, 2.5T transverse and 2.2 GeV, 5T transverse) have a discrepancy <br>in the focal plane between data and simulation. She compared the data divided by the <br>Mott XS to the simulation results without XS, and found that the simulation results <br>of &theta; and &phi; are narrower then the data. JP commented that, while including the Mott<br>XS might change the shape of the distribution, it shouldn't change the boundary. She <br>work on figuring out the cause for this discrepancy before calculating the acceptance. <br>More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07012015/07012015.pdf here].<br />
<br />
*Pengjia<br />
**Comparing asymmetries determined from the MAID model to those calculated from data.<br>Last time he showed a factor of 6 difference between the two results. He determined the <br>scattering angle and Q<sup>2</sup> by fitting the data and compared them to the quantities calculated <br>from MAID. He also showed the results of calculating the quantities g<sub>1</sub>, g<sub>2</sub>, F<sub>1</sub>, F<sub>2</sub>, A<sub>L</sub>, A<sub>T</sub>,<br> dXS<sub>L</sub>, dXS<sub>T</sub>, XS<sub>tot</sub> andXS<sub>mott</sub> using MAID. He hasn't included radiative corrections in his <br>calculations, but this probably won't account for the factor of 6. More details can be seen <br>in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07012015/MAID_20150701.pdf here].<br />
<br />
<br />
----<br />
<br />
==Jan-June 2015==<br />
[[Minutes_Jan2015_to_June2015]]<br />
----<br />
<br />
==July-Dec 2014==<br />
[[Minutes_July2014_to_Dec2014]]<br />
----<br />
<br />
==Jan-June 2014==<br />
[[Minutes_Jan2014_to_June2014]]<br />
----<br />
<br />
==June-Dec 2013==<br />
[[Minutes_June2013_to_Dec2013]]<br />
----<br />
<br />
==Jan-May 2013==<br />
[[Minutes_Jan2013_to_May2013]]<br />
----<br />
<br />
==April-Dec 2012==<br />
[[Minutes_Apr2012_to_Dec2012]]<br />
----<br />
<br />
==Jan-March 2012==<br />
[[Minutes_Jan2012_to_Mar2012]]<br />
----<br />
==July-Dec 2011==<br />
[[Minutes_July2011_to_Dec_2011]]<br />
----<br />
==Jan-June 2011==<br />
[[Minutes_Jan2011_to_June_2011]]<br />
----</div>Melissachttps://hallaweb.jlab.org/wiki/index.php?title=G2p_Weekly_Analysis&diff=26273G2p Weekly Analysis2015-11-11T14:46:02Z<p>Melissac: /* AGENDAS */</p>
<hr />
<div>Analysis meetings are held every Wednesday at 9:00 in F228. ([https://hallaweb.jlab.org/wiki/index.php/G2p_Analysis_Minutes Minutes])<br />
<br />
The conference phone number is 866-740-1260 (US) or 303-248-0285 (International). Access Code: 1466792<br />
<br />
Please edit the agenda to link to your talk prior to the start of the meeting. For help doing this, [https://hallaweb.jlab.org/wiki/index.php/Getting_Started_with_the_g2pWiki click here] <br />
<br />
Group members can post files at /u/group/halla/www/hallaweb/html/experiment/g2p/collaborators, <br><br />
which will then be accessible on the web from http://hallaweb.jlab.org/experiment/g2p/collaborators/<br />
<br />
=AGENDAS=<br />
<br />
'''Wednesday, November 10 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
|[http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/g1_g2/g1g2_11_10.pdf Very Preliminary g1/g2] <br />
|Melissa<br />
|}<br />
<br />
'''Wednesday, November 4 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_11415.pdf g2p Elastic Tail and Angle Reconstruction] <br />
|Ryan<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/yields_update_2015_11_04.pdf Yields Study] <br />
| Jie<br />
|}<br />
<br />
<br />
'''Wednesday, October 28 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Asym/Asym_10_28.pdf Systematic Uncertainties] <br />
| Melissa<br />
|}<br />
<br />
<br />
'''Wednesday, October 14 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/slifer/2015/slifer_g2pcollab_101415.pdf Overview] <br />
| Karl<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/graduate_2015.pdf graduate] <br />
| Pengjia<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/talks/MCummings_CollabMeeting_20151013.pdf update] <br />
| Melissa<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/collaborationupdate.pdf dilution update/outlook] <br />
| Toby<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_10_09_simulation/2015_10_14_collaboration_meeting.pdf Update] <br />
| Jie<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/collab/10142015_collab_Min.pdf Update] <br />
| Min<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20151014/Chao_WeeklyMeeting_10142015.pdf Update] <br />
| Chao<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_101315.pdf Update] <br />
| Ryan<br />
|}<br />
<br />
<br />
'''Wednesday, September 30 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/diltalk_093015.pdf dilution update] <br />
| Toby<br />
|}<br />
<br />
<br />
'''Wednesday, September 23 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/09222015/asym_g12.pdf asymmetry] <br />
| Pengjia<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/09232015.pdf Acceptance Spectrum] <br />
| Min<br />
|}<br />
<br />
<br />
'''Wednesday, September 16 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_09_15_simulation/2015_09_15_Simulation_update.pdf simulation update] <br />
| jie<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_091615.pdf Model Calc. of Physics Quantities] <br />
| Ryan<br />
|}<br />
<br />
<br />
'''Wednesday, September 9 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_09_09_simulation_update/2015_09_09_Simulation%20update.pdf simulation update] <br />
| jie<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150909/Chao_WeeklyMeeting_09092015.pdf Optics Update] <br />
| Chao<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/09092015/asym_20150909.pdf asymmetry] <br />
| Pengjia<br />
|}<br />
<br />
<br />
'''Wednesday, September 2 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Pion/PionAsym_08_31.pdf Pion Asymmetries] <br />
| Melissa<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_09215.pdf Model Calc. of Physics Quantities] <br />
| Ryan<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/acceptance_scatangle.pdf Scattering Angle study contd.] <br />
| Toby<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/09022015.pdf Acceptance Tuning] <br />
| Min<br />
|}<br />
<br />
<br />
'''Wednesday, August 26 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150826/Chao_WeeklyMeeting_08262015.pdf Optics Update] <br />
| Chao<br />
|}<br />
<br />
<br />
'''Wednesday, August 19 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Pion/PionAsym_08_19.pdf Pion Asymmetries] <br />
| Melissa<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/08192015.pdf Acceptance Update] <br />
| Min<br />
|}<br />
<br />
<br />
'''Wednesday, August 12 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150812/Chao_WeeklyMeeting_08122015.pdf Optics Update] <br />
| Chao<br />
|}<br />
<br />
<br />
'''Wednesday, July 29 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07272015/07292015.pdf Acceptance - Optics run] <br />
| Min<br />
|}<br />
<br />
<br />
'''Wednesday, July 22 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_07_22.pdf Epics Checks for Pf Analysis] <br />
| Melissa<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07222015/MAID_update_20150722.pdf MAID update] <br />
| Pengjia<br />
|}<br />
<br />
<br />
'''Wednesday, July 15 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150715/Chao_WeeklyMeeting_07152015.pdf Optics Update] <br />
| Chao<br />
|}<br />
<br />
<br />
'''Wednesday, July 8 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07082015/MAID_update_20150708.pdf MAID update] <br />
| Pengjia<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/scatangle_talk.pdf model reconstruction - scattering angle study] <br />
| Toby<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_07_08.pdf Summary of Pf Analysis ] <br />
| Melissa<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07082015/07062015.pdf Dp Comparison ] <br />
| Min<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150708/Chao_WeeklyMeeting_07082015.pdf Optics Update] <br />
| Chao<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_07_05_plots/2015_07_06_Simulation_update.pdf Simulation Update] <br />
| Jie<br />
|}<br />
<br />
<br />
'''Wednesday, July 1 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07012015/07012015.pdf Acceptance Update] <br />
| Min<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07012015/MAID_20150701.pdf MAID asymmetry] <br />
| Pengjia<br />
|}<br />
<br />
<br />
'''Wednesday, June 24 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Technotes/PF_technote_draft.pdf PF Technote Draft] <br />
| Melissa<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/asymplots.pdf Asymmetry plots] <br />
| Toby<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_06_24_simulation/2015_06_25_Simulation_update.pdf simulation update] <br />
| Jie<br />
<br />
|}<br />
<br />
<br />
'''Wednesday, June 17 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_061715.pdf Pol Rad Corrections] <br />
| Ryan<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/anglecorrection.pdf Angle Correction to simulation] <br />
| Toby<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/06172015/06172015.pdf Acceptance Study - Dilution] <br />
| Min<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/Chao_WeeklyMeeting_06172015.pdf Optics Update] <br />
| Chao<br />
|}<br />
<br />
<br />
'''Wednesday, June 10 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_06_09_simulation/2015_06_10_Simulation_update.pdf Simulation update] <br />
| Jie<br />
|}<br />
<br />
<br />
'''Wednesday, May 27 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/05272015/maid_asym_20150527.pdf Asymmetries from MAID] <br />
| Pengjia<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/05272015/05272015.pdf Acceptance Update 3rd septum] <br />
| Min<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/05272015/Chao_WeeklyMeeting_05272015.pdf Optics Update] <br />
| Chao<br />
|}<br />
<br />
<br />
'''Wednesday, May 20 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/05202015/maid_asym.pdf Asymmetries from MAID] <br />
| Pengjia<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_05_20_snakefield/2015_05_20_hrsfield_update.pdf q1 and septum field] <br />
| Jie<br />
<br />
|}<br />
<br />
<br />
'''Wednesday, May 13 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_05_13_simu_rad_technotes/radiation_simulation_technotes.pdf energy-loss technotes] <br />
| Jie<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/dilutionnote.pdf dilution note] <br />
| Toby<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_05_13.pdf 1.1 GeV Elastic Yields] <br />
| Melissa<br />
|}<br />
<br />
<br />
'''Wednesday, May 6 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150506/Chao_WeeklyMeeting_05062015.pdf Optics Update] <br />
| Chao<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/05062015/05062015.pdf Acceptance Update] <br />
| Min<br />
|}<br />
<br />
<br />
'''Wednesday, April 29 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/04282015/Asymmetries%20for%20different%20raster%20cut.pdf Asymmetries for different raster cut] <br />
| Pengjia<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_04_29.pdf Pf Update] <br />
| Melissa<br />
|}<br />
<br />
<br />
'''Wednesday, April 22 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/technotes/bcm_technote.pdf BCM technote draft] <br />
| Pengjia<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/qualitychecktalk.pdf Quality check summary] <br />
| Toby<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150422/Chao_WeeklyMeeting_04222015.pdf Optics Update] <br />
| Chao<br />
|}<br />
<br />
<br />
'''Wednesday, April 15 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_04_15_acc/2015_04_15_Simulation_update.pdf SIMULATION Update] <br />
| Jie<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_04_15.pdf Pf Update] <br />
| Melissa<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_041515.pdf Rad Corrections] <br />
| Ryan<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/diltalk_041515.pdf Dilution Update] <br />
| Toby<br />
|}<br />
<br />
<br />
'''Wednesday, April 8 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150408/Chao_WeeklyMeeting_04082015.pdf Optics Update] <br />
| Chao<br />
|}<br />
<br />
<br />
'''Wednesday, April 1 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_04_01.pdf PF Update] <br />
| Melissa<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_040115.pdf Model Tune] <br />
| Ryan<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/04012015/04012015.pdf Acceptance Update] <br />
| Min<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_03_31_bpmpos/2015_03_31_Simulation_update.pdf Simulation Update] <br />
| Jie<br />
|}<br />
<br />
<br />
'''Wednesday, March 25 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_03_23_rad_effects/2015_03_25_Simulation_updae.pdf Simulation_update] <br />
| Jie<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/pf_dil_talk.pdf Dilution update] <br />
| Toby<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150325/Chao_WeeklyMeeting_03252015.pdf Optics Update] <br />
| Chao<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/03252015/asym_lr.pdf asymmetry] <br />
| Pengjia<br />
|}<br />
<br />
<br />
'''Wednesday, March 18 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_03_18.pdf Packing Fraction] <br />
| Melissa<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_031715.pdf Model Tune] <br />
| Ryan<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/03182015/03182015.pdf Acceptance Update] <br />
| Min<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/03112015/ Rastercut update] <br />
| Pengjia<br />
|}<br />
<br />
<br />
'''Wednesday, March 11 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_03_06_xs_ratio/2015_03_11_Simulation_updae.pdf simulation update] <br />
| Jie<br />
|}<br />
<br />
<br />
'''Wednesday, March 4 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/diltalk_030415.pdf dilution analysis] <br />
| Toby<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_030415.pdf Model Tune] <br />
| Ryan<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_03_04.pdf Packing Fraction] <br />
| Melissa<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/03042015/03042015.pdf Acceptance Update] <br />
| Min<br />
|}<br />
<br />
<br />
'''Wednesday, February 25 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_02_24_yields/Simulation_update_2015_02_24.pdf yields study] <br />
| Jie<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/technotes/Chao_TechNote_TargetField.pdf TN: Target Field Mapping TN Draft] <br />
| Chao<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/02252015/Position_Cut_20150225.pdf position cut for yields study] <br />
| Pengjia<br />
|}<br />
<br />
<br />
'''Wednesday, February 18 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/02182015/librastercut.pdf rastercut library(not available)] <br />
| Pengjia<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/02182015/02182015.pdf Acceptance Update] <br />
| Min<br />
|}<br />
<br />
<br />
'''Wednesday, February 11 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/dilution021015.pdf Dilution update] <br />
| Toby<br />
|}<br />
<br />
<br />
'''Wednesday, February 4 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Yields/Yields_02_03.pdf Run Quality Check - RHRS] <br />
| Melissa<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150204/Chao_WeeklyMeeting_02042015.pdf RHRS Optics Update] <br />
| Chao<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_02_04_radiative/2015_02_04_Simulation_updae.pdf Simulation update] <br />
| Jie<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/02042015/02042015.pdf Acceptance Update] <br />
| Min<br />
|}<br />
<br />
<br />
'''Wednesday, January 28 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_012815.pdf 1.157 GeV Run Quality Check] <br />
| Ryan<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/01282015/yield_drift_20150128.pdf run quality check] <br />
| Pengjia<br />
|}<br />
<br />
<br />
'''Wednesday, January 21 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Yields/Yields_01_21.pdf Data Quality Check for 2.2GeV, 2.5T] <br />
| Melissa<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150121/Chao_WeeklyMeeting_01212015.pdf RHRS Optics Update] <br />
| Chao<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/01212015/01212015.pdf Acceptance Update] <br />
| Min<br />
|}<br />
<br />
<br />
'''Wednesday, January 14 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/scaler_yield_drift_talk.pdf Yield Drift Study - Scalers] <br />
| Toby<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_011415.pdf 1.157 GeV Run Quality Check] <br />
| Ryan<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_01_12_dp/Simulation_update_2015_01_12.pdf dp] <br />
| Jie<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/01152015/data_quality_20150115.pdf 1.711 GeV run quality check] <br />
| Pengjia<br />
|}<br />
<br />
<br />
'''Wednesday, January 7 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/talks/MCummingsCollabMeeting_Jan.pdf Analysis Updates] <br />
| Melissa<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150107/Chao_WeeklyMeeting_01072015.pdf Optics Update] <br />
| Chao<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/CollabMeeting_12015.pdf Analysis Update] <br />
| Ryan<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/01072015/01072015.pdf Acceptance Update] <br />
| Min<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_01_06_pbosted/2015_01_06_Simulation_update.pdf simulation Update] <br />
| Jie<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/01.07.15.pdf dilution/quality check update] <br />
| Toby<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/01072015/false_asym_20150107.pdf false asymmetry] <br />
| Pengjia<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/slifer/2015/slifer_g2pcollab_010715.pdf Review]<br />
| Karl<br />
|}<br />
<br />
<br />
<br />
==2014==<br />
[[Slides_2014]]<br />
<br />
==2013==<br />
[[Slides_2013]]<br />
<br />
==2012==<br />
[[Slides_2012]]<br />
<br />
==2011==<br />
[[Slides_2011]]</div>Melissachttps://hallaweb.jlab.org/wiki/index.php?title=G2p_Weekly_Analysis&diff=26272G2p Weekly Analysis2015-11-11T14:45:49Z<p>Melissac: /* AGENDAS */</p>
<hr />
<div>Analysis meetings are held every Wednesday at 9:00 in F228. ([https://hallaweb.jlab.org/wiki/index.php/G2p_Analysis_Minutes Minutes])<br />
<br />
The conference phone number is 866-740-1260 (US) or 303-248-0285 (International). Access Code: 1466792<br />
<br />
Please edit the agenda to link to your talk prior to the start of the meeting. For help doing this, [https://hallaweb.jlab.org/wiki/index.php/Getting_Started_with_the_g2pWiki click here] <br />
<br />
Group members can post files at /u/group/halla/www/hallaweb/html/experiment/g2p/collaborators, <br><br />
which will then be accessible on the web from http://hallaweb.jlab.org/experiment/g2p/collaborators/<br />
<br />
=AGENDAS=<br />
<br />
'''Wednesday, November 10 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
|[http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/g1_g2/g1g2_11_10.pdf Preliminary g1/g2] <br />
|Melissa<br />
|}<br />
<br />
'''Wednesday, November 4 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_11415.pdf g2p Elastic Tail and Angle Reconstruction] <br />
|Ryan<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/yields_update_2015_11_04.pdf Yields Study] <br />
| Jie<br />
|}<br />
<br />
<br />
'''Wednesday, October 28 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Asym/Asym_10_28.pdf Systematic Uncertainties] <br />
| Melissa<br />
|}<br />
<br />
<br />
'''Wednesday, October 14 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/slifer/2015/slifer_g2pcollab_101415.pdf Overview] <br />
| Karl<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/graduate_2015.pdf graduate] <br />
| Pengjia<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/talks/MCummings_CollabMeeting_20151013.pdf update] <br />
| Melissa<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/collaborationupdate.pdf dilution update/outlook] <br />
| Toby<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_10_09_simulation/2015_10_14_collaboration_meeting.pdf Update] <br />
| Jie<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/collab/10142015_collab_Min.pdf Update] <br />
| Min<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20151014/Chao_WeeklyMeeting_10142015.pdf Update] <br />
| Chao<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_101315.pdf Update] <br />
| Ryan<br />
|}<br />
<br />
<br />
'''Wednesday, September 30 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/diltalk_093015.pdf dilution update] <br />
| Toby<br />
|}<br />
<br />
<br />
'''Wednesday, September 23 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/09222015/asym_g12.pdf asymmetry] <br />
| Pengjia<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/09232015.pdf Acceptance Spectrum] <br />
| Min<br />
|}<br />
<br />
<br />
'''Wednesday, September 16 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_09_15_simulation/2015_09_15_Simulation_update.pdf simulation update] <br />
| jie<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_091615.pdf Model Calc. of Physics Quantities] <br />
| Ryan<br />
|}<br />
<br />
<br />
'''Wednesday, September 9 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_09_09_simulation_update/2015_09_09_Simulation%20update.pdf simulation update] <br />
| jie<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150909/Chao_WeeklyMeeting_09092015.pdf Optics Update] <br />
| Chao<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/09092015/asym_20150909.pdf asymmetry] <br />
| Pengjia<br />
|}<br />
<br />
<br />
'''Wednesday, September 2 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Pion/PionAsym_08_31.pdf Pion Asymmetries] <br />
| Melissa<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_09215.pdf Model Calc. of Physics Quantities] <br />
| Ryan<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/acceptance_scatangle.pdf Scattering Angle study contd.] <br />
| Toby<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/09022015.pdf Acceptance Tuning] <br />
| Min<br />
|}<br />
<br />
<br />
'''Wednesday, August 26 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150826/Chao_WeeklyMeeting_08262015.pdf Optics Update] <br />
| Chao<br />
|}<br />
<br />
<br />
'''Wednesday, August 19 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Pion/PionAsym_08_19.pdf Pion Asymmetries] <br />
| Melissa<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/08192015.pdf Acceptance Update] <br />
| Min<br />
|}<br />
<br />
<br />
'''Wednesday, August 12 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150812/Chao_WeeklyMeeting_08122015.pdf Optics Update] <br />
| Chao<br />
|}<br />
<br />
<br />
'''Wednesday, July 29 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07272015/07292015.pdf Acceptance - Optics run] <br />
| Min<br />
|}<br />
<br />
<br />
'''Wednesday, July 22 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_07_22.pdf Epics Checks for Pf Analysis] <br />
| Melissa<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07222015/MAID_update_20150722.pdf MAID update] <br />
| Pengjia<br />
|}<br />
<br />
<br />
'''Wednesday, July 15 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150715/Chao_WeeklyMeeting_07152015.pdf Optics Update] <br />
| Chao<br />
|}<br />
<br />
<br />
'''Wednesday, July 8 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07082015/MAID_update_20150708.pdf MAID update] <br />
| Pengjia<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/scatangle_talk.pdf model reconstruction - scattering angle study] <br />
| Toby<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_07_08.pdf Summary of Pf Analysis ] <br />
| Melissa<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07082015/07062015.pdf Dp Comparison ] <br />
| Min<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150708/Chao_WeeklyMeeting_07082015.pdf Optics Update] <br />
| Chao<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_07_05_plots/2015_07_06_Simulation_update.pdf Simulation Update] <br />
| Jie<br />
|}<br />
<br />
<br />
'''Wednesday, July 1 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07012015/07012015.pdf Acceptance Update] <br />
| Min<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07012015/MAID_20150701.pdf MAID asymmetry] <br />
| Pengjia<br />
|}<br />
<br />
<br />
'''Wednesday, June 24 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Technotes/PF_technote_draft.pdf PF Technote Draft] <br />
| Melissa<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/asymplots.pdf Asymmetry plots] <br />
| Toby<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_06_24_simulation/2015_06_25_Simulation_update.pdf simulation update] <br />
| Jie<br />
<br />
|}<br />
<br />
<br />
'''Wednesday, June 17 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_061715.pdf Pol Rad Corrections] <br />
| Ryan<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/anglecorrection.pdf Angle Correction to simulation] <br />
| Toby<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/06172015/06172015.pdf Acceptance Study - Dilution] <br />
| Min<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/Chao_WeeklyMeeting_06172015.pdf Optics Update] <br />
| Chao<br />
|}<br />
<br />
<br />
'''Wednesday, June 10 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_06_09_simulation/2015_06_10_Simulation_update.pdf Simulation update] <br />
| Jie<br />
|}<br />
<br />
<br />
'''Wednesday, May 27 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/05272015/maid_asym_20150527.pdf Asymmetries from MAID] <br />
| Pengjia<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/05272015/05272015.pdf Acceptance Update 3rd septum] <br />
| Min<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/05272015/Chao_WeeklyMeeting_05272015.pdf Optics Update] <br />
| Chao<br />
|}<br />
<br />
<br />
'''Wednesday, May 20 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/05202015/maid_asym.pdf Asymmetries from MAID] <br />
| Pengjia<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_05_20_snakefield/2015_05_20_hrsfield_update.pdf q1 and septum field] <br />
| Jie<br />
<br />
|}<br />
<br />
<br />
'''Wednesday, May 13 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_05_13_simu_rad_technotes/radiation_simulation_technotes.pdf energy-loss technotes] <br />
| Jie<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/dilutionnote.pdf dilution note] <br />
| Toby<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_05_13.pdf 1.1 GeV Elastic Yields] <br />
| Melissa<br />
|}<br />
<br />
<br />
'''Wednesday, May 6 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150506/Chao_WeeklyMeeting_05062015.pdf Optics Update] <br />
| Chao<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/05062015/05062015.pdf Acceptance Update] <br />
| Min<br />
|}<br />
<br />
<br />
'''Wednesday, April 29 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/04282015/Asymmetries%20for%20different%20raster%20cut.pdf Asymmetries for different raster cut] <br />
| Pengjia<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_04_29.pdf Pf Update] <br />
| Melissa<br />
|}<br />
<br />
<br />
'''Wednesday, April 22 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/technotes/bcm_technote.pdf BCM technote draft] <br />
| Pengjia<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/qualitychecktalk.pdf Quality check summary] <br />
| Toby<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150422/Chao_WeeklyMeeting_04222015.pdf Optics Update] <br />
| Chao<br />
|}<br />
<br />
<br />
'''Wednesday, April 15 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_04_15_acc/2015_04_15_Simulation_update.pdf SIMULATION Update] <br />
| Jie<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_04_15.pdf Pf Update] <br />
| Melissa<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_041515.pdf Rad Corrections] <br />
| Ryan<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/diltalk_041515.pdf Dilution Update] <br />
| Toby<br />
|}<br />
<br />
<br />
'''Wednesday, April 8 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150408/Chao_WeeklyMeeting_04082015.pdf Optics Update] <br />
| Chao<br />
|}<br />
<br />
<br />
'''Wednesday, April 1 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_04_01.pdf PF Update] <br />
| Melissa<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_040115.pdf Model Tune] <br />
| Ryan<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/04012015/04012015.pdf Acceptance Update] <br />
| Min<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_03_31_bpmpos/2015_03_31_Simulation_update.pdf Simulation Update] <br />
| Jie<br />
|}<br />
<br />
<br />
'''Wednesday, March 25 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_03_23_rad_effects/2015_03_25_Simulation_updae.pdf Simulation_update] <br />
| Jie<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/pf_dil_talk.pdf Dilution update] <br />
| Toby<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150325/Chao_WeeklyMeeting_03252015.pdf Optics Update] <br />
| Chao<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/03252015/asym_lr.pdf asymmetry] <br />
| Pengjia<br />
|}<br />
<br />
<br />
'''Wednesday, March 18 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_03_18.pdf Packing Fraction] <br />
| Melissa<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_031715.pdf Model Tune] <br />
| Ryan<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/03182015/03182015.pdf Acceptance Update] <br />
| Min<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/03112015/ Rastercut update] <br />
| Pengjia<br />
|}<br />
<br />
<br />
'''Wednesday, March 11 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_03_06_xs_ratio/2015_03_11_Simulation_updae.pdf simulation update] <br />
| Jie<br />
|}<br />
<br />
<br />
'''Wednesday, March 4 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/diltalk_030415.pdf dilution analysis] <br />
| Toby<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_030415.pdf Model Tune] <br />
| Ryan<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_03_04.pdf Packing Fraction] <br />
| Melissa<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/03042015/03042015.pdf Acceptance Update] <br />
| Min<br />
|}<br />
<br />
<br />
'''Wednesday, February 25 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_02_24_yields/Simulation_update_2015_02_24.pdf yields study] <br />
| Jie<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/technotes/Chao_TechNote_TargetField.pdf TN: Target Field Mapping TN Draft] <br />
| Chao<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/02252015/Position_Cut_20150225.pdf position cut for yields study] <br />
| Pengjia<br />
|}<br />
<br />
<br />
'''Wednesday, February 18 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/02182015/librastercut.pdf rastercut library(not available)] <br />
| Pengjia<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/02182015/02182015.pdf Acceptance Update] <br />
| Min<br />
|}<br />
<br />
<br />
'''Wednesday, February 11 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/dilution021015.pdf Dilution update] <br />
| Toby<br />
|}<br />
<br />
<br />
'''Wednesday, February 4 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Yields/Yields_02_03.pdf Run Quality Check - RHRS] <br />
| Melissa<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150204/Chao_WeeklyMeeting_02042015.pdf RHRS Optics Update] <br />
| Chao<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_02_04_radiative/2015_02_04_Simulation_updae.pdf Simulation update] <br />
| Jie<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/02042015/02042015.pdf Acceptance Update] <br />
| Min<br />
|}<br />
<br />
<br />
'''Wednesday, January 28 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_012815.pdf 1.157 GeV Run Quality Check] <br />
| Ryan<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/01282015/yield_drift_20150128.pdf run quality check] <br />
| Pengjia<br />
|}<br />
<br />
<br />
'''Wednesday, January 21 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Yields/Yields_01_21.pdf Data Quality Check for 2.2GeV, 2.5T] <br />
| Melissa<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150121/Chao_WeeklyMeeting_01212015.pdf RHRS Optics Update] <br />
| Chao<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/01212015/01212015.pdf Acceptance Update] <br />
| Min<br />
|}<br />
<br />
<br />
'''Wednesday, January 14 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/scaler_yield_drift_talk.pdf Yield Drift Study - Scalers] <br />
| Toby<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_011415.pdf 1.157 GeV Run Quality Check] <br />
| Ryan<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_01_12_dp/Simulation_update_2015_01_12.pdf dp] <br />
| Jie<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/01152015/data_quality_20150115.pdf 1.711 GeV run quality check] <br />
| Pengjia<br />
|}<br />
<br />
<br />
'''Wednesday, January 7 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/talks/MCummingsCollabMeeting_Jan.pdf Analysis Updates] <br />
| Melissa<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150107/Chao_WeeklyMeeting_01072015.pdf Optics Update] <br />
| Chao<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/CollabMeeting_12015.pdf Analysis Update] <br />
| Ryan<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/01072015/01072015.pdf Acceptance Update] <br />
| Min<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_01_06_pbosted/2015_01_06_Simulation_update.pdf simulation Update] <br />
| Jie<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/01.07.15.pdf dilution/quality check update] <br />
| Toby<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/01072015/false_asym_20150107.pdf false asymmetry] <br />
| Pengjia<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/slifer/2015/slifer_g2pcollab_010715.pdf Review]<br />
| Karl<br />
|}<br />
<br />
<br />
<br />
==2014==<br />
[[Slides_2014]]<br />
<br />
==2013==<br />
[[Slides_2013]]<br />
<br />
==2012==<br />
[[Slides_2012]]<br />
<br />
==2011==<br />
[[Slides_2011]]</div>Melissachttps://hallaweb.jlab.org/wiki/index.php?title=G2p_Analysis_Minutes&diff=26186G2p Analysis Minutes2015-10-29T21:50:06Z<p>Melissac: /* 10/14/2015 */</p>
<hr />
<div>Minutes of the weekly analysis meetings<br />
----<br />
[https://hallaweb.jlab.org/wiki/index.php/G2p_Weekly_Analysis Agenda]<br />
<br />
==10/28/2015==<br />
<br />
Present: JP, Min, Kalyan, Melissa <br><br />
By Phone: Alexandre, Vince, Jie, Ryan, Toby, Ellie, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Gave an overview of contributions to the systematic uncertainty for the asymmetry. There are <br>several contributions which are very small (<0.1%) including the charge asymmetry, livetime <br>asymmetry and pion contamination. The target polarization uncertainty was surprisingly small.<br>The values currently listed in the mysql DB for this quantity appear to be incorrect; Toby will<br>update these values. For the contribution from the dilution factor and radiative corrections, she<br> assigned 5% as a placeholder until a better estimate could be made. Karl/Ryan commented <br>that 5% uncertainty on the radiative corrections may be too small, 10-15% would be a better<br>estimate at this point. The tables shown for the longitudinal and transverse settings represent<br>an overestimate of the uncertainty; in the long-term this could be looked at more carefully to<br>decrease the overall systematic uncertainty. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Asym/Asym_10_28.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*There has been a request from the Hall A CC to have an update on g2p at the winter collaboration <br>meeting. Ellie and Jie are both interested, they will check the dates of the meetings to see if they <br>are available.<br />
<br />
<br />
==10/14/2015==<br />
<br />
Present: JP, Min, Jixie, Kalyan, Melissa <br><br />
By Phone: Alexandre, Vince, Jie, Todd, Haiyan, Pengjia, Karl, Toby, Ryan, Xiaochao, Nilanga, Chao <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Karl<br />
**Went over the goals of the collaboration meeting:<br />
***Discuss physics topics for students graduating soon<br />
***Identify major remaining physics topics<br />
***Establish a policy for the release of plots<br />
**Suggested a policy for collaboration release of physics results, including specific requirements <br>for moving from "very preliminary" to "preliminary" to "final" results. Details can be seen in his <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/slifer/2015/slifer_g2pcollab_101415.pdf here], and they will be circulated to the g2p mailing list with some small modifications.<br />
<br />
*Pengjia<br />
**Will be defending next Wednesday (Oct. 21st). He showed a "very preliminary" physics <br> asymmetry for the 2.2 GeV 5T setting (both longitudinal and transverse) with a comparison to <br> a radiated model prediction. He used this result to extract a preliminary value for g1 and g2,<br>using the Bosted model as input for the cross section. This result does not include radiative<br>corrections. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/graduate_2015.pdf here].<br />
<br />
*Min<br />
**Showed an overview of status of acceptance study; the overall goal is to match the simulation<br>results to the data, so that the simulation can be used to calculate the acceptance. She<br>described the various attempts to correct the simulation results to match the data. Adjusting the<br> apertures based on optics data works well, but the other two methods (adjusting the apertures <br>based on dilution data and adjusting the acceptance cuts after removing the Mott XS from the <br>data) only work well around the target run. In addition, the simulated yield has a different shape <br>than the data, so the simulation must be adjusted to match this. She will go through this process <br>again once Chao is finished with the optics correction. She is planning to graduate next January, <br>and would like to include a cross section difference for one kinematic setting in her thesis. More <br>details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/collab/10142015_collab_Min.pdf here].<br />
<br />
*Melissa<br />
**Gave an overview of packing fraction analysis. Of the 5 total settings there are 3 that are reasonably <br>stable with some small drifts in yields, and 2 settings that have larger problems. During the 2.2 GeV, <br>2.5T setting the raster size was changed, which could possibly be corrected by applying a cut on<br>the center of the raster. The 1.1 GeV setting has large variations in the elastic yields; some of these <br>runs were taken at low currents (8-20nA), so the beam position information is not reliable. She also <br>showed the results of a pion asymmetry study. Although the pion asymmetry is very large, the <br>residual pion contamination after PID cuts are applied is very small, so the correction is not large. <br>She has scheduled her defense for December 4th, and would like to include a preliminary result <br>for g1,g2 in her thesis. To include a fully corrected result she will need preliminary radiative <br>corrections and dilution results, which she will work with Ryan and Toby to get. More details can <br>be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/talks/MCummings_CollabMeeting_20151013.pdf here].<br />
<br />
*Toby<br />
**Showed a preliminary dilution value that he had shown previously, and described several issues <br>with the result. These issues include that the model assumes a constant scattering angle, and does <br>not include some acceptance effects that are seen in the data. He has been working on correcting <br>these issues by incorporating a scattering angle from data into the model and applying acceptance <br>cuts to the data to remove acceptance effects. He showed the result of applying the acceptance cut <br>across all kinematics for the 5T longitudinal setting; including the acceptance cut gets rid of some of <br>the strange structure seen in the yields, such as the sawtooth pattern seen at high nu. The downside <br>of this method is that the acceptance cut causes a large loss in statistics. He is currently working on <br>trying to re-incorporate some of the lost statistics from the acceptance cut. More details can be seen <br>in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/collaborationupdate.pdf here].<br />
<br />
*Jie<br />
**Gave an update on his study using simulation to understand the drifts in yields. He looked at several <br>momentum settings in the 2.2 GeV, 2.5T setting that had variation in the yields. He varied the beam <br>position along the horizontal and vertical directions using both a point beam and rastered beam. He <br>generated a table summarizing the results using a Monte Carlo method, cross checking with averaged <br>acceptance. His results were similar to his previous test using only the Bosted model; some results <br>agree with what was seen in the data, some have the opposite sign. He will write up his method and <br>results in a technote. He is planning to graduate in summer of 2016. More details can be seen in his <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_10_09_simulation/2015_10_14_collaboration_meeting.pdf here].<br />
<br />
*Chao<br />
**Gave an update on optics analysis. Comparisons of simulation with data revealed that the <br>reconstructed kinematics have some offset. A correction was added to the reconstructed kinematics <br>(vs beam position) and he is currently working on merging this correction into the database with a <br>finely tuned fitting procedure. The problem is that the horizontal beam position shifts the dp <br>reconstruction. He showed the results of applying the new optics matrix which corrects for this shift. <br> He will apply this method to all kinematic settings and study the uncertainty of the optics. Once this <br>is done he will write a NIM paper for g2p optics. He plans to graduate in February/March and would <br>like to include the cross section difference for one or two settings with tuned acceptance and model <br>inputs to obtain a physics result. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20151014/Chao_WeeklyMeeting_10142015.pdf here].<br />
<br />
*Ryan<br />
**Since the last collaboration meeting he has improved the model tuning procedure by using an <br>automated procedure instead of tuning the model by hand. He has tested this using carbon data <br>from the UVa database and will run it for nitrogen data once he has updated saGDH N2 cross <br>sections from Vince. He also updated the systematic error study for inelastic unpolarized radiative <br>corrections by separating the integration/iteration error from the interpolation error. He has the <br>polarized radiative correction code running, and has completed a systematic uncertainty study on <br>the inelastic radiative corrections. He is also working on evaluating physics quantities using models, <br>specifically the hyperfine splitting calculation. He plans to graduate in summer/fall of 2016 and would <br>like to include full radiative corrections on g2p polarized cross sections in his thesis. More details can<br> be seen in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_101315.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*Important to do cross checks of results between students (ex. asymmetries)<br />
*Must be careful to include details of any physics results (whether radiative corrections are included,<br>dilution factor, model input instead of data, etc.)<br />
<br />
==9/30/2015==<br />
<br />
Present: JP, Kalyan, Jixie, Min <br><br />
By Phone: Pengjia, Toby, Ryan, Vince, Jie, Chao, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Toby<br />
**Showed an update on his acceptance/dilution study. He continued with the study of the cuts on the <br>reconstructed &theta; vs &phi; distribution at the target. He scanned several different &theta; vs &phi; cuts to see how <br>the acceptance effects the scattering angle and resulting yields. It turns out the small angle region is <br>influenced by the acceptance a lot but the center region gives a good agreement to the model. He <br>also loosed the center cut to &theta; ~ ± 40 mrad and &phi; ~ ± 10 mrad, the data still agreed with the model. <br>He then recalculated the dilution factor for 2.254 GeV longitudinal setting. More details on his <br>acceptance cuts and method can be found in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/diltalk_093015.pdf here].<br />
<br />
<br />
==9/23/2015==<br />
<br />
Present: JP, Kalyan, Min, Melissa <br><br />
By Phone: Pengjia, Toby, Ryan, Vince, Jie, Chao, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Pengjia<br />
**Showed the structure of his code to create a radiated model of the MAID and Bosted <br>models, based on Ryan's radiative correction work. He showed the breakdown of the <br>different components to the radiated model (internal, external and elastic tail). He used<br> the radiated model to calculate an asymmetry and cross section differences, which he <br> compared with data. Finally, he combined asymmetries calculated from data with the <br>Bosted model cross section to calculate a value for g1 and g2, which he compared <br>with values of g1/g2 determined using the MAID model. More details can be seen in <br>his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/09222015/asym_g12.pdf here].<br />
<br />
*Min<br />
**Gave an update on acceptance studies. Last time, she found that by adjusting the<br>apertures in the simulation she could match the data/simulation results for dp (for one <br>momentum setting). She tested this method for other momentum settings and found <br>that it did not work as well. She also showed a comparison of the yield spectrum for<br>helium runs in the 1.7 GeV setting; the shape of the two distributions are quite <br>different, which might suggest that the model deviates significantly form the data. In<br>the simulated results she saw several "bumps" in the yield, which correspond to the<br>location of resonances. She will update these results when the optics corrections are <br>complete. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/09232015.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*We would like to schedule another collaboration meeting in the near future. The <br>meeting is tentatively scheduled for Wednesday October 14th during our usual meeting <br>time (10am-12pm).<br />
*The purpose of the meeting is to:<br />
**Discuss student thesis topics (particularly any updates from the last <br>collaboration meeting)<br />
**Establish a procedure for presentation/release of collaboration plots/results<br />
*Each student should prepare a few slides (~5 minutes) to show analysis progress<br />
<br />
<br />
==9/16/2015==<br />
<br />
Present: Min, JP, Jixie, Melissa <br><br />
By Phone: Vince, Jie, Chao, Pengjia, Alex, Ryan, Toby, Ellie <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Jie<br />
**Gave an update on his simulation study using MUDIFI. Last time he showed that he uses a<br>least square fit to go from endplane to endplane. For the g2p simulation, it's used to go from<br>(x,y,&theta;,&phi;,dp) in the target plane to (x,y,&theta;,&phi;,dp) in the focal plane. SNAKE produces (x,y,&theta;,&phi;,dp)<br>data in both planes and a polynomial function can be used to determine the relationship<br>between the two planes. First the maximum power for each variable is determined, symmetries<br>are included (if applicable), then the priority of each function must be determined. A Gram-<br>Schmidt transformation is used to do the minimization, and the final step is to decide whether<br>to accept the function f<sub>i</sub>. JP/Vince asked how the priority for each function is chosen, since the<br>choice could introduce some ordering dependence. Since we don't have enough data to<br>constrain, JP suggested introducing some physics. He also suggested getting rid of dp in the<br>focal plane (since it is really just dp in the target plane) so that there is one less dimension to<br>fit. More details can be seen in Jie's slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_09_15_simulation/2015_09_15_Simulation_update.pdf here].<br />
<br />
*Ryan<br />
**Gave an update on evaluating physics quantities using models. His goal was to do a<br>comparison of the hyperfine splitting calculation in C. Carlson's 2006/2008 paper using MAID<br>and Hall B models. Previously he showed a comparison using the Hall B model, where he saw<br>good agreement between his calculation and Carlson's result. For this time he also did a<br>comparison using the MAID model. There is a large difference between the two models for the<br>value of the integrand of &Delta;<sub>2</sub>, over the full range of Q<sup>2</sup>. JP suggested comparing the value of g2<br>between the two models, instead of &Delta;<sub>2</sub>. More details can be seen in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_091615.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*Toby<br />
**Last time he showed a comparison between data and cross sections calculated using the<br>Bosted model (seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/acceptance_scatangle.pdf here]). The model was not continuous for one momentum setting. It <br>turns out the BPM was not recording for that setting, so he re-calculated the XS using<br>values for &theta; and &phi; from surrounding runs and found that the result was now consistent with<br>the neighboring momentum settings. He also played around with the acceptance cuts he<br>showed, and found a region using the "extreme cut" where the sawtooth pattern go away<br>and the yields become flat.<br />
<br />
<br />
==9/9/2015==<br />
<br />
Present: Min, JP, Jixie, Melissa <br><br />
By Phone: Vince, Jie, Chao, Ryan, Toby, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Jie<br />
**Gave an overview of his simulation study using SNAKE and MUDIFI. Using SNAKE, the<br>idea is to trace the particle trajectory in a series of free boxes, then an endplane can be<br>defined within the free boxes to determine the trajectory from endplane to endplane. In<br>g2psim this will be used to trace the trajectory between the sieve plane and the focal<br>plane. There are two important issues to consider, the magnetic field in the free boxes,<br>and the transportation method between the two endplanes. A Runge-Kutta method is <br>used for the transportation, and an adaptive method (which changes with field size and<br>gradient) is used to determine the step size. For the magnetic field, a 3D Tosca field<br>map is used for the septum, and an analytic model is used for the spectrometer magnets. <br> He also described the method for choosing the transportation function to determine the <br>25 matrix terms for each kinematic variable (up to 4th order). JP asked how to determine <br>which order is more important, and cautioned to be careful not to over fit the data. He and<br>Jie will discuss this more offline. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_09_09_simulation_update/2015_09_09_Simulation%20update.pdf here].<br />
<br />
*Chao<br />
**Gave an optics status update. The current problem is that changes in the horizontal beam<br>position changes the dp reconstruction. This was fixed by applying a linear correction in<br>BPM-x and BPM-y to &theta;, &phi; and dp. Applying this correction made the data/simulation <br>agree, but it is still necessary to understand the correction. Using dp scan data with beam<br>position scan data still leaves an offset in &theta; and &phi;. He also tried two other methods to do<br>the calibration. Method 1 uses the central hole to determine a constant offset, uses the<br>horizontal beam position scan data to determine all the matrix elements related to y, and<br>uses dp scan runs to fit the additional matrix elements. Method 2 uses beam position<br>scan data to determine the matrix elements that are not related to x<sub>fp</sub>. Neither of these<br>methods works very well, even when the fitting order of the matrix elements are adjusted.<br>He will continue to check more fitting procedures. More details can be found in his slides <br>[http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150909/Chao_WeeklyMeeting_09092015.pdf here].<br />
<br />
*Pengjia<br />
**Gave an update on comparing asymmetries from data/models for the 2.2 GeV, 5T <br>longitudinal setting. He first radiated the Bosted model XS; he showed the break down of<br>the different radiative corrections including the elastic tail (internal and external) and the<br>radiative effects from inelastic scattering. He showed a comparison with Ryan's results<br>which had good agreement, though there is some deviation when he used different proton<br>form factors (provided by Moshe). In order to compare the asymmetry result with data, he<br>needs to do the radiative corrections for the polarized MAID model, which he will continue<br>to work on. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/09092015/asym_20150909.pdf here].<br />
<br />
<br />
==9/2/2015==<br />
<br />
Present: JP, Min, Kalyan, Melissa <br><br />
By Phone: Vince, Alex, Jie, Chao, Ryan, Toby, Ellie, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Gave an update on determining the correction to asymmetries for pion contamination. <br>Previously, she used the 2.2 GeV, 5T longitudinal setting as an example, for this time <br>she used the transverse configuration, as it has the largest pion contamination. She <br>modified her method for differentiating between electrons and pions; previously she <br>identified pions as events that do not trigger the Cherenkov, this time she used a cut <br>below the single photo electron peak to select pions. JP suggested using stricter cuts <br>for selecting pions when determining the pion asymmetry, to make sure it is a clean <br>sample. Although this setting has a large pion contamination, the number of pion<br> events that remain after lead glass cuts are applied is low, so the overall correction <br>is very small. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Pion/PionAsym_08_31.pdf here].<br />
<br />
*Min<br />
**Gave an update on acceptance tuning. She looked at results from the 1.7 GeV setting <br>and found that the height of the peaks is different between data and simulation for <br>different holes in the sieve slit. Looking at the &theta; vs &phi; distribution, she noticed on the<br>positive &theta; side there were fewer holes in simulation than in data, and on the negative <br> &theta; side there were more holes in simulation compared to data. She tried adjusting the<br>aperture cuts by changing the physical location of the Q1, Q2 and septum planes to <br>uncover events that were previously blocked. After the adjustment, the data/simulation <br>results agreed much better. She showed a similar procedure for a dilution run and was<br>able to see better agreement between data/simulation after the aperture adjustments <br>were made. JP/Vince suggested being cautious when adjusting the aperture cuts, as<br> the apertures should be well defined already. They suggested adjusting things that are<br> less well known first, such as the septum field. More details can be seen in her slides<br>[http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/09022015.pdf here].<br />
<br />
*Ryan<br />
**Working on generating physics quantities using models to eventually compare with data.<br>So far, he has incorporated the MAID2007 and Hall B models. He calculated the <br>hyperfine splitting quantities &Delta;1 and &Delta;2 using the Hall B EG1 model and compared them<br> to the results in C. Carlson's 2006 paper. His results agreed very well, he only saw a<br> small deviation for &Delta;2 in the lowest Q<sup>2</sup> range. To check that nothing strange was going <br> on in the low Q<sup>2</sup> range, he calculated &Delta;2 for various small ranges around zero, to ensure<br>that the integration method is well behaved. The Carlson paper also includes calculations <br>using the Simula model, he would like to do a check of this method as well, but is unsure <br>where to find the Simula model. Since he was able to reproduce the hyperfine splitting <br>result, he is confident in his calculation method; it should be straightforward to calculate <br>other spin structure function integrals. More details on his method can be found in his <br>slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_09215.pdf here].<br />
<br />
*Toby<br />
**Showed an update on his acceptance/scattering angle study. He applied cuts of varying<br>strictness on the reconstructed &theta; vs &phi; distribution at the target. He then calculated the <br>real scattering angle before/after scattering for each cut. Using these scattering angles <br> as inputs for the Bosted model he was able to calculate the XS and compare it to data.<br>He showed the comparison between data/Bosted model for each acceptance cut. He <br>hoped that the more extreme acceptance cuts on the data would flatten the yield <br>distribution, but it actually just enhanced the sawtooth pattern. JP questioned why the <br>Bosted prediction for one momentum bin (the green one) was so much lower than the<br> neighboring ones. Toby said the only input that goes into the model is the scattering angle,<br> so it must be considerably different for this momentum setting. He also commented that<br>the model prediction is scaled to match the data, so the scaling enhances the jump in<br>the model. More details on his acceptance cuts and method can be found in his slides<br>[http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/acceptance_scatangle.pdf here].<br />
<br />
<br />
==8/26/2015==<br />
<br />
Present: Jixie, Alex, Min, Kalyan, JP, Chao, Melissa <br><br />
By Phone: Vince, Jie, Ryan, Toby, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Chao<br />
**Gave an update on optics studies. Previously, he showed a comparison between optics data <br>and simulation where he cut on individual sieve holes. For this week, he included a cut on y <br>and dp that he didn't include previously. In the plot of &theta; vs y, JP pointed out that there were <br>additional tails on some sieve holes, Chao says these tails go away when the &phi; cut is <br>included. He showed a 2D plot of &theta; vs &phi;, along with the 1D projection of these variables. JP<br>commented that the data is more smeared out than the simulation, so it is difficult to compare <br>data with simulation results. It's possible that some of the smearing comes from events that <br>punch through the sieve slit and are not being cut out (the simulation currently assumes these <br>events are stopped by the sieve). Looking at the center hole, the data/simulation agree <br>reasonably well, but the agreement gets worse for holes on the edge of the sieve slit. Chao<br>will continue to look into this. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150826/Chao_WeeklyMeeting_08262015.pdf here].<br />
**He also mentioned that ~1 month ago he reported a problem with the [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150708/Chao_WeeklyMeeting_07082015.pdf BPM simulation].<br>He found it was actually a problem with the simulation itself, which has now been updated <br> to correct the problem.<br />
<br />
<br />
'''General Discussion:'''<br />
*Pengjia has submitted his BPM NIM paper.<br />
<br />
<br />
==8/19/2015==<br />
<br />
Present: Chao, Jie, Min, Jixie, Kalyan, Melissa <br><br />
By Phone: Vince, Ryan, Toby, Karl, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Showed a method for determining the correction to asymmetries for pion contamination. The <br>measured asymmetry can be written in terms of the electron and pion asymmetries, multiplied <br>by the fraction of events of that particle. To differentiate between electrons and pions, a cut is<br>made on events that trigger the Cherenkov detector (electrons) and events that do not trigger<br>the Cherenkov (pions). Kalyan commented that this method of selecting pions may be too blind,<br> and suggested making a 2D cut on E/p vs Cherenkov instead. To determine the fraction of<br>electrons/pions, "good event" cuts are applied (loose acceptance cuts, single track events and<br>pion rejector cuts) and the number of electrons/pions that survive the cuts are counted. Although<br>the pion asymmetry is much larger than the electron asymmetry, the number of residual pions<br>is very small, so the overall correction is small. For this example the 2.2 GeV, 5T longitudinal<br>setting was used, but the correction may be larger for the 5T transverse settings, which she <br>will do next. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Pion/PionAsym_08_19.pdf here].<br />
<br />
*Min <br />
**Gave an update on acceptance studies. She used the 1.7 GeV, 2.5T setting (with 3rd septum <br>configuration) to test the acceptance cuts using the yield ratio of data to simulation. She <br>showed a plot of target &theta; vs &phi; for both data and simulation, and applied a graphical cut to get<br>rid of events on the edges. Looking at the resulting 1D plots shows reasonable agreement<br>between &theta; and &phi;. Vince pointed out that there seems to be some additional structure in the<br>dp distribution, and suggested expanding the &delta; cut out to &pm; 4% to see if there is more <br>hidden structure. Min said she has seen this in other settings as well and will look into it. She<br>also tried adjusting the cuts on &theta;, &phi; and &delta; and looked at how the ratio of yields from data/<br>simulation changed; the ratio starts to drop off as the cuts get wider. Next she will work on<br>calculating the yields using W bins. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/08192015.pdf here].<br />
<br />
<br />
==8/12/2015==<br />
<br />
Present: Jie, Chao, Kalyan, Min, Jixie, Melissa <br><br />
By Phone: Pengjia, Ryan, Toby, Karl, Ellie, Alex <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Chao<br />
**Gave an update on optics studies. Previously, Min has shown comparisons of data/simulation<br> where she looked at different columns of sieve holes. Chao continued this study by cutting on <br>individual sieve holes. Looking at the center sieve hole, the &phi; distribution looks reasonable, but <br>the &theta; distribution has some issues. Specifically, the data is wider on the left side (negative &theta;) <br>than the simulation. He showed results for several sieve holes, including one that was in the <br>row as the center hole, but in the farthest column on the left side of the sieve slit. In this case <br>the &theta; distribution had similar width for both data and simulation, but the height of the simulation<br> distribution was larger. This may suggest that something is wrong with the acceptance in the <br>simulation. The problem with &theta; seems to be systematic; for most of the sieve holes there are <br>more events on the left side of the data than in the simulation. Kalyan asked whether the <br>thickness of the sieve slit was taken into account, Chao says it was included in the simulation <br>and optimizer. Jixie suggested comparing the dp distributions for each sieve hole. More details <br>can be seen in Chao's slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150812/Chao_WeeklyMeeting_08122015.pdf here].<br />
<br />
<br />
==7/29/2015==<br />
<br />
Present: Chao, Min, JP, Melissa <br><br />
By Phone: Alex, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Min<br />
**Gave an update on acceptance studies. Previously, Chao showed a correction for the beam<br>position in g2psim. Min checked this correction by looking at optics runs. On the data she <br>applied a cut on dp (to select elastic events) and on the focal plane (to get rid of junk <br> events). On the simulation, only an aperture cut was applied. She compared the data and<br>simulation results for &theta; and &phi; both before and after drifting from the sieve slit to the target.<br>The effect of the target field on &theta; is not very large, though there is a shift down in angle.<br>However, the shape of the &theta; distribution is different between data and simulation. The<br>effect of the target field on &phi; is significant; it's not clear why this is the case. To try to<br>determine the reason for the discrepancies, she applied a cut along each column of sieve<br>slit holes in &phi; and compared the data and simulation results for &theta;,&phi; and dp. Column 2<br>seems to have the best agreement (for dp), columns 1 and 2 have a shift while columns<br>3-6 have a difference in width. Chao suggested also cutting along each row of sieve slit<br>holes to better study the effect of the drift on &phi;. Min will work on identifying the differences<br>between data and simulation, specifically whether the boundaries are different between<br>the two. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07272015/07292015.pdf here].<br />
<br />
<br />
==7/22/2015==<br />
<br />
Present: JP, Min, Jixie, Melissa <br><br />
By Phone: Alex, Ryan, Toby, Ellie, Karl, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Showed various checks for packing fraction runs that have large discrepancies, including <br>beam position, beam energy, spectrometer central momentum setting, septum current, and<br>the location of anneals. For both the 2.2 and 1.1 GeV settings, there are significant shifts in <br>the x and y beam position (2mm or more). She showed the average and standard deviation <br> of epics readings for the LHRS septum current for each run. For several runs, there are small <br>number of epics readings that drift from the average current. It's not clear if this is the <br>current is actually changing or if it is a readout problem. She will look into the yield vs time<br>to try to determine this. JP suggested making a raster cut on the center of the beam to get<br> rid of any potential scraping. Pengjia says there is a way to cut on raster size, but there will<br> be an additional BPM uncertainty. Melissa will discuss this more offline with Pengjia. More<br>details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_07_22.pdf here].<br />
<br />
*Pengjia<br />
**Gave an update on calculating asymmetries/cross sections using the MAID model. This time, <br>he used the Bosted model to get the unpolarized cross sections for the proton. Using unradiated <br>cross section models, he still saw a factor of 6 difference when compared with data. Ryan also <br>calculated asymmetries using unradiated models, and the results were consistent with Pengjia's, <br>so it seems the radiative effects contribute significantly to the factor of 6 difference. More <br>details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07222015/MAID_update_20150722.pdf here].<br />
<br />
<br />
==7/15/2015==<br />
<br />
Present: JP, Min, Chao, Jixie, Melissa <br><br />
By Phone: Ryan, Toby, Ellie, Karl, Vince, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Chao<br />
**Doing a check of simulation/data results for the 2.2 GeV, longitudinal setting in order <br>to check that the optics calibration matrix will work for all momentum settings (not <br>just elastic). He showed a comparison for several different momentum settings.<br> Vince suggested simulating more events, since the statistics start to drop off for <br>lower momentum settings. In general, the data is broader then the result from<br>simulation. In the &theta; distribution, the "tails" seen in the data are not symmetric. JP<br> suggested carefully selecting cuts to remove any background from the data to <br>ensure a good comparison with simulation. More details can be seen in his <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150715/Chao_WeeklyMeeting_07152015.pdf here].<br />
<br />
*Pengjia<br />
**More discussion on Pengjia's [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07082015/MAID_update_20150708.pdf slides] from last week. Pengjia has seen a factor of <br>six difference between his asymmetry calculated from data compared to the <br>asymmetry determined using the MAID model. Ryan did not see this factor of six <br>in his study, but in addition to using radiated XS models, he is using a combination <br>of the Bosted and MAID models (Pengjia is using just the MAID model). Karl <br>commented that the XS from MAID is not very good for our kinematics. Pengjia <br>also showed an estimated NH3 XS. JP commented that it was surprising that the <br>delta peak wasn't visible. Pengjia will look into this for next time.<br />
<br />
<br />
==7/8/2015==<br />
<br />
Present: JP, Min, Chao, Melissa <br><br />
By Phone: Toby, Vince <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Pengjia<br />
**Working on comparing asymmetries determined from MAID to those calculated from <br>data; last time he showed a factor of 6 difference between the two results. This <br>time, he showed two different methods for calculating the differential XS from the <br>virtual photon XS. The first method calculates the differential XS directly from <br>the virtual photon XS, and the second method calculates the differential XS using <br>F<sub>1</sub>, F<sub>2</sub>, g<sub>1</sub> and g<sub>2</sub>. He also showed two different methods for calculating the <br>asymmetry from the virtual photon XS; one method uses A<sub>1</sub> and A<sub>2</sub>, while the other <br>is calculated from the virtual photon XS. There was a discrepancy between the two <br>methods, but he found that there was actually a mistake in one of the equations. <br>While the results from the two methods agree with each other, they are still a factor <br>of 6 larger than the results from data. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07082015/MAID_update_20150708.pdf here].<br />
<br />
*Toby<br />
**Showed an update of his scattering angle study for model reconstruction. He is <br>using BPM and optics data to determine the scattering angle. He showed an example <br>of the calculated scattering angle; JP questioned whether the range was really from <br>0-16 deg. Toby pointed out that there really aren't many events at the boundaries, <br>the distribution is peaked between 4.5-9 deg. He then uses this scattering angle as<br>input for the Bosted model. At low &nu; the simulation results match reasonably well<br>with the data, but the discrepancy starts to become larger as &nu; increases. He took <br>a closer look at the reconstructed scattering angle for each central momentum, and <br>found that a second peak is visible for smaller values of p0. If this second peak was <br>real, the simulation should recreate the data, so this could suggest a problem with <br>the reconstruction. However, Chao pointed out that, for this energy setting, the optics <br>calibration is not complete (currently using the longitudinal optics matrix), so the <br>reconstructed &theta; and &phi; may not be correct yet. For next time, Toby will test this <br>analysis using the 1.7 GeV setting, which has calibrated optics. More details can <br> be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/scatangle_talk.pdf here].<br />
<br />
*Melissa<br />
**Gave a summary of packing fraction analysis. For some settings, the variation in the <br>yields (and P<sub>f</sub>) is due to a fluctuation in the beam position. This will hopefully be<br>resolved by Jie's beam position/acceptance study. For the 2.2 GeV, 2.5T transverse setting<br> there is also an issue of a shift in &nu; between runs. For the 1.1 GeV, 2.5T transverse <br>setting, the yields vary depending on the beam current used for each run. JP suggested <br>a few things to check as the possible cause for these discrepancies including drift in the <br>BCM calibration, anneals of the target material, drift in field (HRS or septum), etc. She <br>has posted a technote draft [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Technotes/PF_technote_draft.pdf here], feedback would be appreciated. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_07_08.pdf here].<br />
<br />
*Min<br />
**Gave an update on her acceptance study. Last time, she showed that the simulation results <br>are more narrow than the data. For this time, she tried cutting on just the center hole, <br>and found that the dp distribution from data better matched the simulation. JP suggested <br>cutting on each of the different holes individually to determine which hole causes the dp <br>distribution to be wider. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07082015/07062015.pdf here].<br />
<br />
*Chao<br />
**Gave an update on optics analysis, currently checking whether simulation results match <br>with data, starting with optics data. First he checked whether the geometry was correct, <br>some deviation was found in the recent optics meeting. The position of the BPMs is hard-<br>coded into the simulation, and the drifting algorithm is used to drift the electrons <br>backward to the BPMs to simulate the readout of BPM A and B. He compared the &theta; <br>distribution before drifting in the target field using a fixed and non-fixed BPM location. <br>The results using a fixed BPM match well with the data. He is currently working on <br>checking this for all momentum settings, and will follow up with Pengjia about the BPM <br>problem. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150708/Chao_WeeklyMeeting_07082015.pdf here].<br />
<br />
<br />
==7/1/2015==<br />
<br />
Present: Chao, Vince, Jie, JP, Min, Melissa <br><br />
By Phone: Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Min<br />
**Gave an update on acceptance studies. She showed a summary table of each energy <br>setting and septum configuration. There hasn't been any problems in the 2.2 GeV, 5T <br>longitudinal and 1.7 GeV, 2.5T transverse settings, but some settings (2.2 GeV, 2.5T <br> transverse, 1.2 GeV, 2.5T transverse and 2.2 GeV, 5T transverse) have a discrepancy <br>in the focal plane between data and simulation. She compared the data divided by the <br>Mott XS to the simulation results without XS, and found that the simulation results <br>of &theta; and &phi; are narrower then the data. JP commented that, while including the Mott<br>XS might change the shape of the distribution, it shouldn't change the boundary. She <br>work on figuring out the cause for this discrepancy before calculating the acceptance. <br>More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07012015/07012015.pdf here].<br />
<br />
*Pengjia<br />
**Comparing asymmetries determined from the MAID model to those calculated from data.<br>Last time he showed a factor of 6 difference between the two results. He determined the <br>scattering angle and Q<sup>2</sup> by fitting the data and compared them to the quantities calculated <br>from MAID. He also showed the results of calculating the quantities g<sub>1</sub>, g<sub>2</sub>, F<sub>1</sub>, F<sub>2</sub>, A<sub>L</sub>, A<sub>T</sub>,<br> dXS<sub>L</sub>, dXS<sub>T</sub>, XS<sub>tot</sub> andXS<sub>mott</sub> using MAID. He hasn't included radiative corrections in his <br>calculations, but this probably won't account for the factor of 6. More details can be seen <br>in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07012015/MAID_20150701.pdf here].<br />
<br />
<br />
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<br />
==Jan-June 2015==<br />
[[Minutes_Jan2015_to_June2015]]<br />
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<br />
==July-Dec 2014==<br />
[[Minutes_July2014_to_Dec2014]]<br />
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<br />
==Jan-June 2014==<br />
[[Minutes_Jan2014_to_June2014]]<br />
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<br />
==June-Dec 2013==<br />
[[Minutes_June2013_to_Dec2013]]<br />
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<br />
==Jan-May 2013==<br />
[[Minutes_Jan2013_to_May2013]]<br />
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<br />
==April-Dec 2012==<br />
[[Minutes_Apr2012_to_Dec2012]]<br />
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<br />
==Jan-March 2012==<br />
[[Minutes_Jan2012_to_Mar2012]]<br />
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==July-Dec 2011==<br />
[[Minutes_July2011_to_Dec_2011]]<br />
----<br />
==Jan-June 2011==<br />
[[Minutes_Jan2011_to_June_2011]]<br />
----</div>Melissachttps://hallaweb.jlab.org/wiki/index.php?title=G2p_Analysis_Minutes&diff=26185G2p Analysis Minutes2015-10-29T21:49:28Z<p>Melissac: /* 10/14/2015 */</p>
<hr />
<div>Minutes of the weekly analysis meetings<br />
----<br />
[https://hallaweb.jlab.org/wiki/index.php/G2p_Weekly_Analysis Agenda]<br />
<br />
==10/28/2015==<br />
<br />
Present: JP, Min, Kalyan, Melissa <br><br />
By Phone: Alexandre, Vince, Jie, Ryan, Toby, Ellie, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Gave an overview of contributions to the systematic uncertainty for the asymmetry. There are <br>several contributions which are very small (<0.1%) including the charge asymmetry, livetime <br>asymmetry and pion contamination. The target polarization uncertainty was surprisingly small.<br>The values currently listed in the mysql DB for this quantity appear to be incorrect; Toby will<br>update these values. For the contribution from the dilution factor and radiative corrections, she<br> assigned 5% as a placeholder until a better estimate could be made. Karl/Ryan commented <br>that 5% uncertainty on the radiative corrections may be too small, 10-15% would be a better<br>estimate at this point. The tables shown for the longitudinal and transverse settings represent<br>an overestimate of the uncertainty; in the long-term this could be looked at more carefully to<br>decrease the overall systematic uncertainty. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Asym/Asym_10_28.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*There has been a request from the Hall A CC to have an update on g2p at the winter collaboration <br>meeting. Ellie and Jie are both interested, they will check the dates of the meetings to see if they <br>are available.<br />
<br />
==10/14/2015==<br />
<br />
Present: JP, Min, Jixie, Kalyan, Melissa <br><br />
By Phone: Alexandre, Vince, Jie, Todd, Haiyan, Pengjia, Karl, Toby, Ryan, Xiaochao, Nilanga, Chao <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Karl<br />
**Went over the goals of the collaboration meeting:<br />
***Discuss physics topics for students graduating soon<br />
***Identify major remaining physics topics<br />
***Establish a policy for the release of plots<br />
**Suggested a policy for collaboration release of physics results, including specific requirements <br>for moving from "very preliminary" to "preliminary" to "final" results. Details can be seen in his <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/slifer/2015/slifer_g2pcollab_101415.pdf here], and they will be circulated to the g2p mailing list with some small modifications.<br />
<br />
*Pengjia<br />
**Will be defending next Wednesday (Oct. 21st). He showed a "very preliminary" physics <br> asymmetry for the 2.2 GeV 5T setting (both longitudinal and transverse) with a comparison to <br> a radiated model prediction. He used this result to extract a preliminary value for g1 and g2,<br>using the Bosted model as input for the cross section. This result does not include radiative<br>corrections. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/graduate_2015.pdf here].<br />
<br />
*Min<br />
**Showed an overview of status of acceptance study; the overall goal is to match the simulation<br>results to the data, so that the simulation can be used to calculate the acceptance. She<br>described the various attempts to correct the simulation results to match the data. Adjusting the<br> apertures based on optics data works well, but the other two methods (adjusting the apertures <br>based on dilution data and adjusting the acceptance cuts after removing the Mott XS from the <br>data) only work well around the target run. In addition, the simulated yield has a different shape <br>than the data, so the simulation must be adjusted to match this. She will go through this process <br>again once Chao is finished with the optics correction. She is planning to graduate next January, <br>and would like to include a cross section difference for one kinematic setting in her thesis. More <br>details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/collab/10142015_collab_Min.pdf here].<br />
<br />
*Melissa<br />
**Gave an overview of packing fraction analysis. Of the 5 total settings there are 3 that are reasonably <br>stable with some small drifts in yields, and 2 settings that have larger problems. During the 2.2 GeV, <br>2.5T setting the raster size was changed, which could possibly be corrected by applying a cut on<br>the center of the raster. The 1.1 GeV setting has large variations in the elastic yields; some of these <br>runs were taken at low currents (8-20nA), so the beam position information is not reliable. She also <br>showed the results of a pion asymmetry study. Although the pion asymmetry is very large, the <br>residual pion contamination after PID cuts are applied is very small, so the correction is not large. <br>She has scheduled her defense for December 4th, and would like to include a preliminary result <br>for g1,g2 in her thesis. To include a fully corrected result she will need preliminary radiative <br>corrections and dilution results, which she will work with Ryan and Toby to get. More details can <br>be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/talks/MCummings_CollabMeeting_20151013.pdf here].<br />
<br />
*Toby<br />
**Showed a preliminary dilution value that he had shown previously, and described several issues <br>with the result. These issues include that the model assumes a constant scattering angle, and does <br>not include some acceptance effects that are seen in the data. He has been working on correcting <br>these issues by incorporating a scattering angle from data into the model and applying acceptance <br>cuts to the data to remove acceptance effects. He showed the result of applying the acceptance cut <br>across all kinematics for the 5T longitudinal setting; including the acceptance cut gets rid of some of <br>the strange structure seen in the yields, such as the sawtooth pattern seen at high nu. The downside <br>of this method is that the acceptance cut causes a large loss in statistics. He is currently working on <br>trying to re-incorporate some of the lost statistics from the acceptance cut. More details can be seen <br>in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/collaborationupdate.pdf here].<br />
<br />
*Jie<br />
**Gave an update on his study using simulation to understand the drifts in yields. He looked at several <br>momentum settings in the 2.2 GeV, 2.5T setting that had variation in the yields. He varied the beam <br>position along the horizontal and vertical directions using both a point beam and rastered beam. He <br>generated a table summarizing the results using a Monte Carlo method, cross checking with averaged <br>acceptance. His results were similar to his previous test using only the Bosted model; some results <br>agree with what was seen in the data, some have the opposite sign. He will write up his method and <br>results in a technote. He is planning to graduate in summer of 2016. More details can be seen in his <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_10_09_simulation/2015_10_14_collaboration_meeting.pdf here].<br />
<br />
*Chao<br />
**Gave an update on optics analysis. Comparisons of simulation with data revealed that the <br>reconstructed kinematics have some offset. A correction was added to the reconstructed kinematics <br>(vs beam position) and he is currently working on merging this correction into the database with a <br>finely tuned fitting procedure. The problem is that the horizontal beam position shifts the dp <br>reconstruction. He showed the results of applying the new optics matrix which corrects for this shift. <br> He will apply this method to all kinematic settings and study the uncertainty of the optics. Once this <br>is done he will write a NIM paper for g2p optics. He plans to graduate in February/March and would <br>like to include the cross section difference for one or two settings with tuned acceptance and model <br>inputs to obtain a physics result. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20151014/Chao_WeeklyMeeting_10142015.pdf here].<br />
<br />
*Ryan<br />
**Since the last collaboration meeting he has improved the model tuning procedure by using an <br>automated procedure instead of tuning the model by hand. He has tested this using carbon data <br>from the UVa database and will run it for nitrogen data once he has updated saGDH N2 cross <br>sections from Vince. He also updated the systematic error study for inelastic unpolarized radiative <br>corrections by separating the integration/iteration error from the interpolation error. He has the <br>polarized radiative correction code running, and has completed a systematic uncertainty study on <br>the inelastic radiative corrections. He is also working on evaluating physics quantities using models, <br>specifically the hyperfine splitting calculation. He plans to graduate in summer/fall of 2016 and would <br>like to include full radiative corrections on g2p polarized cross sections in his thesis. More details can<br> be seen in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_101315.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*Important to do cross checks of results between students (ex. asymmetries)<br />
*Must be careful to include details of any physics results (whether radiative corrections are included,<br>dilution factor, model input instead of data, etc.)<br />
<br />
==9/30/2015==<br />
<br />
Present: JP, Kalyan, Jixie, Min <br><br />
By Phone: Pengjia, Toby, Ryan, Vince, Jie, Chao, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Toby<br />
**Showed an update on his acceptance/dilution study. He continued with the study of the cuts on the <br>reconstructed &theta; vs &phi; distribution at the target. He scanned several different &theta; vs &phi; cuts to see how <br>the acceptance effects the scattering angle and resulting yields. It turns out the small angle region is <br>influenced by the acceptance a lot but the center region gives a good agreement to the model. He <br>also loosed the center cut to &theta; ~ ± 40 mrad and &phi; ~ ± 10 mrad, the data still agreed with the model. <br>He then recalculated the dilution factor for 2.254 GeV longitudinal setting. More details on his <br>acceptance cuts and method can be found in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/diltalk_093015.pdf here].<br />
<br />
<br />
==9/23/2015==<br />
<br />
Present: JP, Kalyan, Min, Melissa <br><br />
By Phone: Pengjia, Toby, Ryan, Vince, Jie, Chao, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Pengjia<br />
**Showed the structure of his code to create a radiated model of the MAID and Bosted <br>models, based on Ryan's radiative correction work. He showed the breakdown of the <br>different components to the radiated model (internal, external and elastic tail). He used<br> the radiated model to calculate an asymmetry and cross section differences, which he <br> compared with data. Finally, he combined asymmetries calculated from data with the <br>Bosted model cross section to calculate a value for g1 and g2, which he compared <br>with values of g1/g2 determined using the MAID model. More details can be seen in <br>his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/09222015/asym_g12.pdf here].<br />
<br />
*Min<br />
**Gave an update on acceptance studies. Last time, she found that by adjusting the<br>apertures in the simulation she could match the data/simulation results for dp (for one <br>momentum setting). She tested this method for other momentum settings and found <br>that it did not work as well. She also showed a comparison of the yield spectrum for<br>helium runs in the 1.7 GeV setting; the shape of the two distributions are quite <br>different, which might suggest that the model deviates significantly form the data. In<br>the simulated results she saw several "bumps" in the yield, which correspond to the<br>location of resonances. She will update these results when the optics corrections are <br>complete. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/09232015.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*We would like to schedule another collaboration meeting in the near future. The <br>meeting is tentatively scheduled for Wednesday October 14th during our usual meeting <br>time (10am-12pm).<br />
*The purpose of the meeting is to:<br />
**Discuss student thesis topics (particularly any updates from the last <br>collaboration meeting)<br />
**Establish a procedure for presentation/release of collaboration plots/results<br />
*Each student should prepare a few slides (~5 minutes) to show analysis progress<br />
<br />
<br />
==9/16/2015==<br />
<br />
Present: Min, JP, Jixie, Melissa <br><br />
By Phone: Vince, Jie, Chao, Pengjia, Alex, Ryan, Toby, Ellie <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Jie<br />
**Gave an update on his simulation study using MUDIFI. Last time he showed that he uses a<br>least square fit to go from endplane to endplane. For the g2p simulation, it's used to go from<br>(x,y,&theta;,&phi;,dp) in the target plane to (x,y,&theta;,&phi;,dp) in the focal plane. SNAKE produces (x,y,&theta;,&phi;,dp)<br>data in both planes and a polynomial function can be used to determine the relationship<br>between the two planes. First the maximum power for each variable is determined, symmetries<br>are included (if applicable), then the priority of each function must be determined. A Gram-<br>Schmidt transformation is used to do the minimization, and the final step is to decide whether<br>to accept the function f<sub>i</sub>. JP/Vince asked how the priority for each function is chosen, since the<br>choice could introduce some ordering dependence. Since we don't have enough data to<br>constrain, JP suggested introducing some physics. He also suggested getting rid of dp in the<br>focal plane (since it is really just dp in the target plane) so that there is one less dimension to<br>fit. More details can be seen in Jie's slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_09_15_simulation/2015_09_15_Simulation_update.pdf here].<br />
<br />
*Ryan<br />
**Gave an update on evaluating physics quantities using models. His goal was to do a<br>comparison of the hyperfine splitting calculation in C. Carlson's 2006/2008 paper using MAID<br>and Hall B models. Previously he showed a comparison using the Hall B model, where he saw<br>good agreement between his calculation and Carlson's result. For this time he also did a<br>comparison using the MAID model. There is a large difference between the two models for the<br>value of the integrand of &Delta;<sub>2</sub>, over the full range of Q<sup>2</sup>. JP suggested comparing the value of g2<br>between the two models, instead of &Delta;<sub>2</sub>. More details can be seen in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_091615.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*Toby<br />
**Last time he showed a comparison between data and cross sections calculated using the<br>Bosted model (seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/acceptance_scatangle.pdf here]). The model was not continuous for one momentum setting. It <br>turns out the BPM was not recording for that setting, so he re-calculated the XS using<br>values for &theta; and &phi; from surrounding runs and found that the result was now consistent with<br>the neighboring momentum settings. He also played around with the acceptance cuts he<br>showed, and found a region using the "extreme cut" where the sawtooth pattern go away<br>and the yields become flat.<br />
<br />
<br />
==9/9/2015==<br />
<br />
Present: Min, JP, Jixie, Melissa <br><br />
By Phone: Vince, Jie, Chao, Ryan, Toby, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Jie<br />
**Gave an overview of his simulation study using SNAKE and MUDIFI. Using SNAKE, the<br>idea is to trace the particle trajectory in a series of free boxes, then an endplane can be<br>defined within the free boxes to determine the trajectory from endplane to endplane. In<br>g2psim this will be used to trace the trajectory between the sieve plane and the focal<br>plane. There are two important issues to consider, the magnetic field in the free boxes,<br>and the transportation method between the two endplanes. A Runge-Kutta method is <br>used for the transportation, and an adaptive method (which changes with field size and<br>gradient) is used to determine the step size. For the magnetic field, a 3D Tosca field<br>map is used for the septum, and an analytic model is used for the spectrometer magnets. <br> He also described the method for choosing the transportation function to determine the <br>25 matrix terms for each kinematic variable (up to 4th order). JP asked how to determine <br>which order is more important, and cautioned to be careful not to over fit the data. He and<br>Jie will discuss this more offline. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_09_09_simulation_update/2015_09_09_Simulation%20update.pdf here].<br />
<br />
*Chao<br />
**Gave an optics status update. The current problem is that changes in the horizontal beam<br>position changes the dp reconstruction. This was fixed by applying a linear correction in<br>BPM-x and BPM-y to &theta;, &phi; and dp. Applying this correction made the data/simulation <br>agree, but it is still necessary to understand the correction. Using dp scan data with beam<br>position scan data still leaves an offset in &theta; and &phi;. He also tried two other methods to do<br>the calibration. Method 1 uses the central hole to determine a constant offset, uses the<br>horizontal beam position scan data to determine all the matrix elements related to y, and<br>uses dp scan runs to fit the additional matrix elements. Method 2 uses beam position<br>scan data to determine the matrix elements that are not related to x<sub>fp</sub>. Neither of these<br>methods works very well, even when the fitting order of the matrix elements are adjusted.<br>He will continue to check more fitting procedures. More details can be found in his slides <br>[http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150909/Chao_WeeklyMeeting_09092015.pdf here].<br />
<br />
*Pengjia<br />
**Gave an update on comparing asymmetries from data/models for the 2.2 GeV, 5T <br>longitudinal setting. He first radiated the Bosted model XS; he showed the break down of<br>the different radiative corrections including the elastic tail (internal and external) and the<br>radiative effects from inelastic scattering. He showed a comparison with Ryan's results<br>which had good agreement, though there is some deviation when he used different proton<br>form factors (provided by Moshe). In order to compare the asymmetry result with data, he<br>needs to do the radiative corrections for the polarized MAID model, which he will continue<br>to work on. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/09092015/asym_20150909.pdf here].<br />
<br />
<br />
==9/2/2015==<br />
<br />
Present: JP, Min, Kalyan, Melissa <br><br />
By Phone: Vince, Alex, Jie, Chao, Ryan, Toby, Ellie, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Gave an update on determining the correction to asymmetries for pion contamination. <br>Previously, she used the 2.2 GeV, 5T longitudinal setting as an example, for this time <br>she used the transverse configuration, as it has the largest pion contamination. She <br>modified her method for differentiating between electrons and pions; previously she <br>identified pions as events that do not trigger the Cherenkov, this time she used a cut <br>below the single photo electron peak to select pions. JP suggested using stricter cuts <br>for selecting pions when determining the pion asymmetry, to make sure it is a clean <br>sample. Although this setting has a large pion contamination, the number of pion<br> events that remain after lead glass cuts are applied is low, so the overall correction <br>is very small. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Pion/PionAsym_08_31.pdf here].<br />
<br />
*Min<br />
**Gave an update on acceptance tuning. She looked at results from the 1.7 GeV setting <br>and found that the height of the peaks is different between data and simulation for <br>different holes in the sieve slit. Looking at the &theta; vs &phi; distribution, she noticed on the<br>positive &theta; side there were fewer holes in simulation than in data, and on the negative <br> &theta; side there were more holes in simulation compared to data. She tried adjusting the<br>aperture cuts by changing the physical location of the Q1, Q2 and septum planes to <br>uncover events that were previously blocked. After the adjustment, the data/simulation <br>results agreed much better. She showed a similar procedure for a dilution run and was<br>able to see better agreement between data/simulation after the aperture adjustments <br>were made. JP/Vince suggested being cautious when adjusting the aperture cuts, as<br> the apertures should be well defined already. They suggested adjusting things that are<br> less well known first, such as the septum field. More details can be seen in her slides<br>[http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/09022015.pdf here].<br />
<br />
*Ryan<br />
**Working on generating physics quantities using models to eventually compare with data.<br>So far, he has incorporated the MAID2007 and Hall B models. He calculated the <br>hyperfine splitting quantities &Delta;1 and &Delta;2 using the Hall B EG1 model and compared them<br> to the results in C. Carlson's 2006 paper. His results agreed very well, he only saw a<br> small deviation for &Delta;2 in the lowest Q<sup>2</sup> range. To check that nothing strange was going <br> on in the low Q<sup>2</sup> range, he calculated &Delta;2 for various small ranges around zero, to ensure<br>that the integration method is well behaved. The Carlson paper also includes calculations <br>using the Simula model, he would like to do a check of this method as well, but is unsure <br>where to find the Simula model. Since he was able to reproduce the hyperfine splitting <br>result, he is confident in his calculation method; it should be straightforward to calculate <br>other spin structure function integrals. More details on his method can be found in his <br>slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_09215.pdf here].<br />
<br />
*Toby<br />
**Showed an update on his acceptance/scattering angle study. He applied cuts of varying<br>strictness on the reconstructed &theta; vs &phi; distribution at the target. He then calculated the <br>real scattering angle before/after scattering for each cut. Using these scattering angles <br> as inputs for the Bosted model he was able to calculate the XS and compare it to data.<br>He showed the comparison between data/Bosted model for each acceptance cut. He <br>hoped that the more extreme acceptance cuts on the data would flatten the yield <br>distribution, but it actually just enhanced the sawtooth pattern. JP questioned why the <br>Bosted prediction for one momentum bin (the green one) was so much lower than the<br> neighboring ones. Toby said the only input that goes into the model is the scattering angle,<br> so it must be considerably different for this momentum setting. He also commented that<br>the model prediction is scaled to match the data, so the scaling enhances the jump in<br>the model. More details on his acceptance cuts and method can be found in his slides<br>[http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/acceptance_scatangle.pdf here].<br />
<br />
<br />
==8/26/2015==<br />
<br />
Present: Jixie, Alex, Min, Kalyan, JP, Chao, Melissa <br><br />
By Phone: Vince, Jie, Ryan, Toby, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Chao<br />
**Gave an update on optics studies. Previously, he showed a comparison between optics data <br>and simulation where he cut on individual sieve holes. For this week, he included a cut on y <br>and dp that he didn't include previously. In the plot of &theta; vs y, JP pointed out that there were <br>additional tails on some sieve holes, Chao says these tails go away when the &phi; cut is <br>included. He showed a 2D plot of &theta; vs &phi;, along with the 1D projection of these variables. JP<br>commented that the data is more smeared out than the simulation, so it is difficult to compare <br>data with simulation results. It's possible that some of the smearing comes from events that <br>punch through the sieve slit and are not being cut out (the simulation currently assumes these <br>events are stopped by the sieve). Looking at the center hole, the data/simulation agree <br>reasonably well, but the agreement gets worse for holes on the edge of the sieve slit. Chao<br>will continue to look into this. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150826/Chao_WeeklyMeeting_08262015.pdf here].<br />
**He also mentioned that ~1 month ago he reported a problem with the [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150708/Chao_WeeklyMeeting_07082015.pdf BPM simulation].<br>He found it was actually a problem with the simulation itself, which has now been updated <br> to correct the problem.<br />
<br />
<br />
'''General Discussion:'''<br />
*Pengjia has submitted his BPM NIM paper.<br />
<br />
<br />
==8/19/2015==<br />
<br />
Present: Chao, Jie, Min, Jixie, Kalyan, Melissa <br><br />
By Phone: Vince, Ryan, Toby, Karl, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Showed a method for determining the correction to asymmetries for pion contamination. The <br>measured asymmetry can be written in terms of the electron and pion asymmetries, multiplied <br>by the fraction of events of that particle. To differentiate between electrons and pions, a cut is<br>made on events that trigger the Cherenkov detector (electrons) and events that do not trigger<br>the Cherenkov (pions). Kalyan commented that this method of selecting pions may be too blind,<br> and suggested making a 2D cut on E/p vs Cherenkov instead. To determine the fraction of<br>electrons/pions, "good event" cuts are applied (loose acceptance cuts, single track events and<br>pion rejector cuts) and the number of electrons/pions that survive the cuts are counted. Although<br>the pion asymmetry is much larger than the electron asymmetry, the number of residual pions<br>is very small, so the overall correction is small. For this example the 2.2 GeV, 5T longitudinal<br>setting was used, but the correction may be larger for the 5T transverse settings, which she <br>will do next. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Pion/PionAsym_08_19.pdf here].<br />
<br />
*Min <br />
**Gave an update on acceptance studies. She used the 1.7 GeV, 2.5T setting (with 3rd septum <br>configuration) to test the acceptance cuts using the yield ratio of data to simulation. She <br>showed a plot of target &theta; vs &phi; for both data and simulation, and applied a graphical cut to get<br>rid of events on the edges. Looking at the resulting 1D plots shows reasonable agreement<br>between &theta; and &phi;. Vince pointed out that there seems to be some additional structure in the<br>dp distribution, and suggested expanding the &delta; cut out to &pm; 4% to see if there is more <br>hidden structure. Min said she has seen this in other settings as well and will look into it. She<br>also tried adjusting the cuts on &theta;, &phi; and &delta; and looked at how the ratio of yields from data/<br>simulation changed; the ratio starts to drop off as the cuts get wider. Next she will work on<br>calculating the yields using W bins. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/08192015.pdf here].<br />
<br />
<br />
==8/12/2015==<br />
<br />
Present: Jie, Chao, Kalyan, Min, Jixie, Melissa <br><br />
By Phone: Pengjia, Ryan, Toby, Karl, Ellie, Alex <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Chao<br />
**Gave an update on optics studies. Previously, Min has shown comparisons of data/simulation<br> where she looked at different columns of sieve holes. Chao continued this study by cutting on <br>individual sieve holes. Looking at the center sieve hole, the &phi; distribution looks reasonable, but <br>the &theta; distribution has some issues. Specifically, the data is wider on the left side (negative &theta;) <br>than the simulation. He showed results for several sieve holes, including one that was in the <br>row as the center hole, but in the farthest column on the left side of the sieve slit. In this case <br>the &theta; distribution had similar width for both data and simulation, but the height of the simulation<br> distribution was larger. This may suggest that something is wrong with the acceptance in the <br>simulation. The problem with &theta; seems to be systematic; for most of the sieve holes there are <br>more events on the left side of the data than in the simulation. Kalyan asked whether the <br>thickness of the sieve slit was taken into account, Chao says it was included in the simulation <br>and optimizer. Jixie suggested comparing the dp distributions for each sieve hole. More details <br>can be seen in Chao's slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150812/Chao_WeeklyMeeting_08122015.pdf here].<br />
<br />
<br />
==7/29/2015==<br />
<br />
Present: Chao, Min, JP, Melissa <br><br />
By Phone: Alex, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Min<br />
**Gave an update on acceptance studies. Previously, Chao showed a correction for the beam<br>position in g2psim. Min checked this correction by looking at optics runs. On the data she <br>applied a cut on dp (to select elastic events) and on the focal plane (to get rid of junk <br> events). On the simulation, only an aperture cut was applied. She compared the data and<br>simulation results for &theta; and &phi; both before and after drifting from the sieve slit to the target.<br>The effect of the target field on &theta; is not very large, though there is a shift down in angle.<br>However, the shape of the &theta; distribution is different between data and simulation. The<br>effect of the target field on &phi; is significant; it's not clear why this is the case. To try to<br>determine the reason for the discrepancies, she applied a cut along each column of sieve<br>slit holes in &phi; and compared the data and simulation results for &theta;,&phi; and dp. Column 2<br>seems to have the best agreement (for dp), columns 1 and 2 have a shift while columns<br>3-6 have a difference in width. Chao suggested also cutting along each row of sieve slit<br>holes to better study the effect of the drift on &phi;. Min will work on identifying the differences<br>between data and simulation, specifically whether the boundaries are different between<br>the two. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07272015/07292015.pdf here].<br />
<br />
<br />
==7/22/2015==<br />
<br />
Present: JP, Min, Jixie, Melissa <br><br />
By Phone: Alex, Ryan, Toby, Ellie, Karl, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Showed various checks for packing fraction runs that have large discrepancies, including <br>beam position, beam energy, spectrometer central momentum setting, septum current, and<br>the location of anneals. For both the 2.2 and 1.1 GeV settings, there are significant shifts in <br>the x and y beam position (2mm or more). She showed the average and standard deviation <br> of epics readings for the LHRS septum current for each run. For several runs, there are small <br>number of epics readings that drift from the average current. It's not clear if this is the <br>current is actually changing or if it is a readout problem. She will look into the yield vs time<br>to try to determine this. JP suggested making a raster cut on the center of the beam to get<br> rid of any potential scraping. Pengjia says there is a way to cut on raster size, but there will<br> be an additional BPM uncertainty. Melissa will discuss this more offline with Pengjia. More<br>details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_07_22.pdf here].<br />
<br />
*Pengjia<br />
**Gave an update on calculating asymmetries/cross sections using the MAID model. This time, <br>he used the Bosted model to get the unpolarized cross sections for the proton. Using unradiated <br>cross section models, he still saw a factor of 6 difference when compared with data. Ryan also <br>calculated asymmetries using unradiated models, and the results were consistent with Pengjia's, <br>so it seems the radiative effects contribute significantly to the factor of 6 difference. More <br>details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07222015/MAID_update_20150722.pdf here].<br />
<br />
<br />
==7/15/2015==<br />
<br />
Present: JP, Min, Chao, Jixie, Melissa <br><br />
By Phone: Ryan, Toby, Ellie, Karl, Vince, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Chao<br />
**Doing a check of simulation/data results for the 2.2 GeV, longitudinal setting in order <br>to check that the optics calibration matrix will work for all momentum settings (not <br>just elastic). He showed a comparison for several different momentum settings.<br> Vince suggested simulating more events, since the statistics start to drop off for <br>lower momentum settings. In general, the data is broader then the result from<br>simulation. In the &theta; distribution, the "tails" seen in the data are not symmetric. JP<br> suggested carefully selecting cuts to remove any background from the data to <br>ensure a good comparison with simulation. More details can be seen in his <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150715/Chao_WeeklyMeeting_07152015.pdf here].<br />
<br />
*Pengjia<br />
**More discussion on Pengjia's [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07082015/MAID_update_20150708.pdf slides] from last week. Pengjia has seen a factor of <br>six difference between his asymmetry calculated from data compared to the <br>asymmetry determined using the MAID model. Ryan did not see this factor of six <br>in his study, but in addition to using radiated XS models, he is using a combination <br>of the Bosted and MAID models (Pengjia is using just the MAID model). Karl <br>commented that the XS from MAID is not very good for our kinematics. Pengjia <br>also showed an estimated NH3 XS. JP commented that it was surprising that the <br>delta peak wasn't visible. Pengjia will look into this for next time.<br />
<br />
<br />
==7/8/2015==<br />
<br />
Present: JP, Min, Chao, Melissa <br><br />
By Phone: Toby, Vince <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Pengjia<br />
**Working on comparing asymmetries determined from MAID to those calculated from <br>data; last time he showed a factor of 6 difference between the two results. This <br>time, he showed two different methods for calculating the differential XS from the <br>virtual photon XS. The first method calculates the differential XS directly from <br>the virtual photon XS, and the second method calculates the differential XS using <br>F<sub>1</sub>, F<sub>2</sub>, g<sub>1</sub> and g<sub>2</sub>. He also showed two different methods for calculating the <br>asymmetry from the virtual photon XS; one method uses A<sub>1</sub> and A<sub>2</sub>, while the other <br>is calculated from the virtual photon XS. There was a discrepancy between the two <br>methods, but he found that there was actually a mistake in one of the equations. <br>While the results from the two methods agree with each other, they are still a factor <br>of 6 larger than the results from data. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07082015/MAID_update_20150708.pdf here].<br />
<br />
*Toby<br />
**Showed an update of his scattering angle study for model reconstruction. He is <br>using BPM and optics data to determine the scattering angle. He showed an example <br>of the calculated scattering angle; JP questioned whether the range was really from <br>0-16 deg. Toby pointed out that there really aren't many events at the boundaries, <br>the distribution is peaked between 4.5-9 deg. He then uses this scattering angle as<br>input for the Bosted model. At low &nu; the simulation results match reasonably well<br>with the data, but the discrepancy starts to become larger as &nu; increases. He took <br>a closer look at the reconstructed scattering angle for each central momentum, and <br>found that a second peak is visible for smaller values of p0. If this second peak was <br>real, the simulation should recreate the data, so this could suggest a problem with <br>the reconstruction. However, Chao pointed out that, for this energy setting, the optics <br>calibration is not complete (currently using the longitudinal optics matrix), so the <br>reconstructed &theta; and &phi; may not be correct yet. For next time, Toby will test this <br>analysis using the 1.7 GeV setting, which has calibrated optics. More details can <br> be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/scatangle_talk.pdf here].<br />
<br />
*Melissa<br />
**Gave a summary of packing fraction analysis. For some settings, the variation in the <br>yields (and P<sub>f</sub>) is due to a fluctuation in the beam position. This will hopefully be<br>resolved by Jie's beam position/acceptance study. For the 2.2 GeV, 2.5T transverse setting<br> there is also an issue of a shift in &nu; between runs. For the 1.1 GeV, 2.5T transverse <br>setting, the yields vary depending on the beam current used for each run. JP suggested <br>a few things to check as the possible cause for these discrepancies including drift in the <br>BCM calibration, anneals of the target material, drift in field (HRS or septum), etc. She <br>has posted a technote draft [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Technotes/PF_technote_draft.pdf here], feedback would be appreciated. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_07_08.pdf here].<br />
<br />
*Min<br />
**Gave an update on her acceptance study. Last time, she showed that the simulation results <br>are more narrow than the data. For this time, she tried cutting on just the center hole, <br>and found that the dp distribution from data better matched the simulation. JP suggested <br>cutting on each of the different holes individually to determine which hole causes the dp <br>distribution to be wider. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07082015/07062015.pdf here].<br />
<br />
*Chao<br />
**Gave an update on optics analysis, currently checking whether simulation results match <br>with data, starting with optics data. First he checked whether the geometry was correct, <br>some deviation was found in the recent optics meeting. The position of the BPMs is hard-<br>coded into the simulation, and the drifting algorithm is used to drift the electrons <br>backward to the BPMs to simulate the readout of BPM A and B. He compared the &theta; <br>distribution before drifting in the target field using a fixed and non-fixed BPM location. <br>The results using a fixed BPM match well with the data. He is currently working on <br>checking this for all momentum settings, and will follow up with Pengjia about the BPM <br>problem. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150708/Chao_WeeklyMeeting_07082015.pdf here].<br />
<br />
<br />
==7/1/2015==<br />
<br />
Present: Chao, Vince, Jie, JP, Min, Melissa <br><br />
By Phone: Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Min<br />
**Gave an update on acceptance studies. She showed a summary table of each energy <br>setting and septum configuration. There hasn't been any problems in the 2.2 GeV, 5T <br>longitudinal and 1.7 GeV, 2.5T transverse settings, but some settings (2.2 GeV, 2.5T <br> transverse, 1.2 GeV, 2.5T transverse and 2.2 GeV, 5T transverse) have a discrepancy <br>in the focal plane between data and simulation. She compared the data divided by the <br>Mott XS to the simulation results without XS, and found that the simulation results <br>of &theta; and &phi; are narrower then the data. JP commented that, while including the Mott<br>XS might change the shape of the distribution, it shouldn't change the boundary. She <br>work on figuring out the cause for this discrepancy before calculating the acceptance. <br>More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07012015/07012015.pdf here].<br />
<br />
*Pengjia<br />
**Comparing asymmetries determined from the MAID model to those calculated from data.<br>Last time he showed a factor of 6 difference between the two results. He determined the <br>scattering angle and Q<sup>2</sup> by fitting the data and compared them to the quantities calculated <br>from MAID. He also showed the results of calculating the quantities g<sub>1</sub>, g<sub>2</sub>, F<sub>1</sub>, F<sub>2</sub>, A<sub>L</sub>, A<sub>T</sub>,<br> dXS<sub>L</sub>, dXS<sub>T</sub>, XS<sub>tot</sub> andXS<sub>mott</sub> using MAID. He hasn't included radiative corrections in his <br>calculations, but this probably won't account for the factor of 6. More details can be seen <br>in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07012015/MAID_20150701.pdf here].<br />
<br />
<br />
----<br />
<br />
==Jan-June 2015==<br />
[[Minutes_Jan2015_to_June2015]]<br />
----<br />
<br />
==July-Dec 2014==<br />
[[Minutes_July2014_to_Dec2014]]<br />
----<br />
<br />
==Jan-June 2014==<br />
[[Minutes_Jan2014_to_June2014]]<br />
----<br />
<br />
==June-Dec 2013==<br />
[[Minutes_June2013_to_Dec2013]]<br />
----<br />
<br />
==Jan-May 2013==<br />
[[Minutes_Jan2013_to_May2013]]<br />
----<br />
<br />
==April-Dec 2012==<br />
[[Minutes_Apr2012_to_Dec2012]]<br />
----<br />
<br />
==Jan-March 2012==<br />
[[Minutes_Jan2012_to_Mar2012]]<br />
----<br />
==July-Dec 2011==<br />
[[Minutes_July2011_to_Dec_2011]]<br />
----<br />
==Jan-June 2011==<br />
[[Minutes_Jan2011_to_June_2011]]<br />
----</div>Melissachttps://hallaweb.jlab.org/wiki/index.php?title=G2p_Analysis_Minutes&diff=26184G2p Analysis Minutes2015-10-29T21:49:19Z<p>Melissac: /* 10/14/2015 */</p>
<hr />
<div>Minutes of the weekly analysis meetings<br />
----<br />
[https://hallaweb.jlab.org/wiki/index.php/G2p_Weekly_Analysis Agenda]<br />
<br />
==10/14/2015==<br />
<br />
Present: JP, Min, Kalyan, Melissa <br><br />
By Phone: Alexandre, Vince, Jie, Ryan, Toby, Ellie, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Gave an overview of contributions to the systematic uncertainty for the asymmetry. There are <br>several contributions which are very small (<0.1%) including the charge asymmetry, livetime <br>asymmetry and pion contamination. The target polarization uncertainty was surprisingly small.<br>The values currently listed in the mysql DB for this quantity appear to be incorrect; Toby will<br>update these values. For the contribution from the dilution factor and radiative corrections, she<br> assigned 5% as a placeholder until a better estimate could be made. Karl/Ryan commented <br>that 5% uncertainty on the radiative corrections may be too small, 10-15% would be a better<br>estimate at this point. The tables shown for the longitudinal and transverse settings represent<br>an overestimate of the uncertainty; in the long-term this could be looked at more carefully to<br>decrease the overall systematic uncertainty. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Asym/Asym_10_28.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*There has been a request from the Hall A CC to have an update on g2p at the winter collaboration <br>meeting. Ellie and Jie are both interested, they will check the dates of the meetings to see if they <br>are available.<br />
<br />
<br />
<br />
==10/14/2015==<br />
<br />
Present: JP, Min, Jixie, Kalyan, Melissa <br><br />
By Phone: Alexandre, Vince, Jie, Todd, Haiyan, Pengjia, Karl, Toby, Ryan, Xiaochao, Nilanga, Chao <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Karl<br />
**Went over the goals of the collaboration meeting:<br />
***Discuss physics topics for students graduating soon<br />
***Identify major remaining physics topics<br />
***Establish a policy for the release of plots<br />
**Suggested a policy for collaboration release of physics results, including specific requirements <br>for moving from "very preliminary" to "preliminary" to "final" results. Details can be seen in his <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/slifer/2015/slifer_g2pcollab_101415.pdf here], and they will be circulated to the g2p mailing list with some small modifications.<br />
<br />
*Pengjia<br />
**Will be defending next Wednesday (Oct. 21st). He showed a "very preliminary" physics <br> asymmetry for the 2.2 GeV 5T setting (both longitudinal and transverse) with a comparison to <br> a radiated model prediction. He used this result to extract a preliminary value for g1 and g2,<br>using the Bosted model as input for the cross section. This result does not include radiative<br>corrections. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/graduate_2015.pdf here].<br />
<br />
*Min<br />
**Showed an overview of status of acceptance study; the overall goal is to match the simulation<br>results to the data, so that the simulation can be used to calculate the acceptance. She<br>described the various attempts to correct the simulation results to match the data. Adjusting the<br> apertures based on optics data works well, but the other two methods (adjusting the apertures <br>based on dilution data and adjusting the acceptance cuts after removing the Mott XS from the <br>data) only work well around the target run. In addition, the simulated yield has a different shape <br>than the data, so the simulation must be adjusted to match this. She will go through this process <br>again once Chao is finished with the optics correction. She is planning to graduate next January, <br>and would like to include a cross section difference for one kinematic setting in her thesis. More <br>details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/collab/10142015_collab_Min.pdf here].<br />
<br />
*Melissa<br />
**Gave an overview of packing fraction analysis. Of the 5 total settings there are 3 that are reasonably <br>stable with some small drifts in yields, and 2 settings that have larger problems. During the 2.2 GeV, <br>2.5T setting the raster size was changed, which could possibly be corrected by applying a cut on<br>the center of the raster. The 1.1 GeV setting has large variations in the elastic yields; some of these <br>runs were taken at low currents (8-20nA), so the beam position information is not reliable. She also <br>showed the results of a pion asymmetry study. Although the pion asymmetry is very large, the <br>residual pion contamination after PID cuts are applied is very small, so the correction is not large. <br>She has scheduled her defense for December 4th, and would like to include a preliminary result <br>for g1,g2 in her thesis. To include a fully corrected result she will need preliminary radiative <br>corrections and dilution results, which she will work with Ryan and Toby to get. More details can <br>be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/talks/MCummings_CollabMeeting_20151013.pdf here].<br />
<br />
*Toby<br />
**Showed a preliminary dilution value that he had shown previously, and described several issues <br>with the result. These issues include that the model assumes a constant scattering angle, and does <br>not include some acceptance effects that are seen in the data. He has been working on correcting <br>these issues by incorporating a scattering angle from data into the model and applying acceptance <br>cuts to the data to remove acceptance effects. He showed the result of applying the acceptance cut <br>across all kinematics for the 5T longitudinal setting; including the acceptance cut gets rid of some of <br>the strange structure seen in the yields, such as the sawtooth pattern seen at high nu. The downside <br>of this method is that the acceptance cut causes a large loss in statistics. He is currently working on <br>trying to re-incorporate some of the lost statistics from the acceptance cut. More details can be seen <br>in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/collaborationupdate.pdf here].<br />
<br />
*Jie<br />
**Gave an update on his study using simulation to understand the drifts in yields. He looked at several <br>momentum settings in the 2.2 GeV, 2.5T setting that had variation in the yields. He varied the beam <br>position along the horizontal and vertical directions using both a point beam and rastered beam. He <br>generated a table summarizing the results using a Monte Carlo method, cross checking with averaged <br>acceptance. His results were similar to his previous test using only the Bosted model; some results <br>agree with what was seen in the data, some have the opposite sign. He will write up his method and <br>results in a technote. He is planning to graduate in summer of 2016. More details can be seen in his <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_10_09_simulation/2015_10_14_collaboration_meeting.pdf here].<br />
<br />
*Chao<br />
**Gave an update on optics analysis. Comparisons of simulation with data revealed that the <br>reconstructed kinematics have some offset. A correction was added to the reconstructed kinematics <br>(vs beam position) and he is currently working on merging this correction into the database with a <br>finely tuned fitting procedure. The problem is that the horizontal beam position shifts the dp <br>reconstruction. He showed the results of applying the new optics matrix which corrects for this shift. <br> He will apply this method to all kinematic settings and study the uncertainty of the optics. Once this <br>is done he will write a NIM paper for g2p optics. He plans to graduate in February/March and would <br>like to include the cross section difference for one or two settings with tuned acceptance and model <br>inputs to obtain a physics result. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20151014/Chao_WeeklyMeeting_10142015.pdf here].<br />
<br />
*Ryan<br />
**Since the last collaboration meeting he has improved the model tuning procedure by using an <br>automated procedure instead of tuning the model by hand. He has tested this using carbon data <br>from the UVa database and will run it for nitrogen data once he has updated saGDH N2 cross <br>sections from Vince. He also updated the systematic error study for inelastic unpolarized radiative <br>corrections by separating the integration/iteration error from the interpolation error. He has the <br>polarized radiative correction code running, and has completed a systematic uncertainty study on <br>the inelastic radiative corrections. He is also working on evaluating physics quantities using models, <br>specifically the hyperfine splitting calculation. He plans to graduate in summer/fall of 2016 and would <br>like to include full radiative corrections on g2p polarized cross sections in his thesis. More details can<br> be seen in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_101315.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*Important to do cross checks of results between students (ex. asymmetries)<br />
*Must be careful to include details of any physics results (whether radiative corrections are included,<br>dilution factor, model input instead of data, etc.)<br />
<br />
==9/30/2015==<br />
<br />
Present: JP, Kalyan, Jixie, Min <br><br />
By Phone: Pengjia, Toby, Ryan, Vince, Jie, Chao, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Toby<br />
**Showed an update on his acceptance/dilution study. He continued with the study of the cuts on the <br>reconstructed &theta; vs &phi; distribution at the target. He scanned several different &theta; vs &phi; cuts to see how <br>the acceptance effects the scattering angle and resulting yields. It turns out the small angle region is <br>influenced by the acceptance a lot but the center region gives a good agreement to the model. He <br>also loosed the center cut to &theta; ~ ± 40 mrad and &phi; ~ ± 10 mrad, the data still agreed with the model. <br>He then recalculated the dilution factor for 2.254 GeV longitudinal setting. More details on his <br>acceptance cuts and method can be found in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/diltalk_093015.pdf here].<br />
<br />
<br />
==9/23/2015==<br />
<br />
Present: JP, Kalyan, Min, Melissa <br><br />
By Phone: Pengjia, Toby, Ryan, Vince, Jie, Chao, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Pengjia<br />
**Showed the structure of his code to create a radiated model of the MAID and Bosted <br>models, based on Ryan's radiative correction work. He showed the breakdown of the <br>different components to the radiated model (internal, external and elastic tail). He used<br> the radiated model to calculate an asymmetry and cross section differences, which he <br> compared with data. Finally, he combined asymmetries calculated from data with the <br>Bosted model cross section to calculate a value for g1 and g2, which he compared <br>with values of g1/g2 determined using the MAID model. More details can be seen in <br>his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/09222015/asym_g12.pdf here].<br />
<br />
*Min<br />
**Gave an update on acceptance studies. Last time, she found that by adjusting the<br>apertures in the simulation she could match the data/simulation results for dp (for one <br>momentum setting). She tested this method for other momentum settings and found <br>that it did not work as well. She also showed a comparison of the yield spectrum for<br>helium runs in the 1.7 GeV setting; the shape of the two distributions are quite <br>different, which might suggest that the model deviates significantly form the data. In<br>the simulated results she saw several "bumps" in the yield, which correspond to the<br>location of resonances. She will update these results when the optics corrections are <br>complete. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/09232015.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*We would like to schedule another collaboration meeting in the near future. The <br>meeting is tentatively scheduled for Wednesday October 14th during our usual meeting <br>time (10am-12pm).<br />
*The purpose of the meeting is to:<br />
**Discuss student thesis topics (particularly any updates from the last <br>collaboration meeting)<br />
**Establish a procedure for presentation/release of collaboration plots/results<br />
*Each student should prepare a few slides (~5 minutes) to show analysis progress<br />
<br />
<br />
==9/16/2015==<br />
<br />
Present: Min, JP, Jixie, Melissa <br><br />
By Phone: Vince, Jie, Chao, Pengjia, Alex, Ryan, Toby, Ellie <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Jie<br />
**Gave an update on his simulation study using MUDIFI. Last time he showed that he uses a<br>least square fit to go from endplane to endplane. For the g2p simulation, it's used to go from<br>(x,y,&theta;,&phi;,dp) in the target plane to (x,y,&theta;,&phi;,dp) in the focal plane. SNAKE produces (x,y,&theta;,&phi;,dp)<br>data in both planes and a polynomial function can be used to determine the relationship<br>between the two planes. First the maximum power for each variable is determined, symmetries<br>are included (if applicable), then the priority of each function must be determined. A Gram-<br>Schmidt transformation is used to do the minimization, and the final step is to decide whether<br>to accept the function f<sub>i</sub>. JP/Vince asked how the priority for each function is chosen, since the<br>choice could introduce some ordering dependence. Since we don't have enough data to<br>constrain, JP suggested introducing some physics. He also suggested getting rid of dp in the<br>focal plane (since it is really just dp in the target plane) so that there is one less dimension to<br>fit. More details can be seen in Jie's slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_09_15_simulation/2015_09_15_Simulation_update.pdf here].<br />
<br />
*Ryan<br />
**Gave an update on evaluating physics quantities using models. His goal was to do a<br>comparison of the hyperfine splitting calculation in C. Carlson's 2006/2008 paper using MAID<br>and Hall B models. Previously he showed a comparison using the Hall B model, where he saw<br>good agreement between his calculation and Carlson's result. For this time he also did a<br>comparison using the MAID model. There is a large difference between the two models for the<br>value of the integrand of &Delta;<sub>2</sub>, over the full range of Q<sup>2</sup>. JP suggested comparing the value of g2<br>between the two models, instead of &Delta;<sub>2</sub>. More details can be seen in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_091615.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*Toby<br />
**Last time he showed a comparison between data and cross sections calculated using the<br>Bosted model (seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/acceptance_scatangle.pdf here]). The model was not continuous for one momentum setting. It <br>turns out the BPM was not recording for that setting, so he re-calculated the XS using<br>values for &theta; and &phi; from surrounding runs and found that the result was now consistent with<br>the neighboring momentum settings. He also played around with the acceptance cuts he<br>showed, and found a region using the "extreme cut" where the sawtooth pattern go away<br>and the yields become flat.<br />
<br />
<br />
==9/9/2015==<br />
<br />
Present: Min, JP, Jixie, Melissa <br><br />
By Phone: Vince, Jie, Chao, Ryan, Toby, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Jie<br />
**Gave an overview of his simulation study using SNAKE and MUDIFI. Using SNAKE, the<br>idea is to trace the particle trajectory in a series of free boxes, then an endplane can be<br>defined within the free boxes to determine the trajectory from endplane to endplane. In<br>g2psim this will be used to trace the trajectory between the sieve plane and the focal<br>plane. There are two important issues to consider, the magnetic field in the free boxes,<br>and the transportation method between the two endplanes. A Runge-Kutta method is <br>used for the transportation, and an adaptive method (which changes with field size and<br>gradient) is used to determine the step size. For the magnetic field, a 3D Tosca field<br>map is used for the septum, and an analytic model is used for the spectrometer magnets. <br> He also described the method for choosing the transportation function to determine the <br>25 matrix terms for each kinematic variable (up to 4th order). JP asked how to determine <br>which order is more important, and cautioned to be careful not to over fit the data. He and<br>Jie will discuss this more offline. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_09_09_simulation_update/2015_09_09_Simulation%20update.pdf here].<br />
<br />
*Chao<br />
**Gave an optics status update. The current problem is that changes in the horizontal beam<br>position changes the dp reconstruction. This was fixed by applying a linear correction in<br>BPM-x and BPM-y to &theta;, &phi; and dp. Applying this correction made the data/simulation <br>agree, but it is still necessary to understand the correction. Using dp scan data with beam<br>position scan data still leaves an offset in &theta; and &phi;. He also tried two other methods to do<br>the calibration. Method 1 uses the central hole to determine a constant offset, uses the<br>horizontal beam position scan data to determine all the matrix elements related to y, and<br>uses dp scan runs to fit the additional matrix elements. Method 2 uses beam position<br>scan data to determine the matrix elements that are not related to x<sub>fp</sub>. Neither of these<br>methods works very well, even when the fitting order of the matrix elements are adjusted.<br>He will continue to check more fitting procedures. More details can be found in his slides <br>[http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150909/Chao_WeeklyMeeting_09092015.pdf here].<br />
<br />
*Pengjia<br />
**Gave an update on comparing asymmetries from data/models for the 2.2 GeV, 5T <br>longitudinal setting. He first radiated the Bosted model XS; he showed the break down of<br>the different radiative corrections including the elastic tail (internal and external) and the<br>radiative effects from inelastic scattering. He showed a comparison with Ryan's results<br>which had good agreement, though there is some deviation when he used different proton<br>form factors (provided by Moshe). In order to compare the asymmetry result with data, he<br>needs to do the radiative corrections for the polarized MAID model, which he will continue<br>to work on. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/09092015/asym_20150909.pdf here].<br />
<br />
<br />
==9/2/2015==<br />
<br />
Present: JP, Min, Kalyan, Melissa <br><br />
By Phone: Vince, Alex, Jie, Chao, Ryan, Toby, Ellie, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Gave an update on determining the correction to asymmetries for pion contamination. <br>Previously, she used the 2.2 GeV, 5T longitudinal setting as an example, for this time <br>she used the transverse configuration, as it has the largest pion contamination. She <br>modified her method for differentiating between electrons and pions; previously she <br>identified pions as events that do not trigger the Cherenkov, this time she used a cut <br>below the single photo electron peak to select pions. JP suggested using stricter cuts <br>for selecting pions when determining the pion asymmetry, to make sure it is a clean <br>sample. Although this setting has a large pion contamination, the number of pion<br> events that remain after lead glass cuts are applied is low, so the overall correction <br>is very small. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Pion/PionAsym_08_31.pdf here].<br />
<br />
*Min<br />
**Gave an update on acceptance tuning. She looked at results from the 1.7 GeV setting <br>and found that the height of the peaks is different between data and simulation for <br>different holes in the sieve slit. Looking at the &theta; vs &phi; distribution, she noticed on the<br>positive &theta; side there were fewer holes in simulation than in data, and on the negative <br> &theta; side there were more holes in simulation compared to data. She tried adjusting the<br>aperture cuts by changing the physical location of the Q1, Q2 and septum planes to <br>uncover events that were previously blocked. After the adjustment, the data/simulation <br>results agreed much better. She showed a similar procedure for a dilution run and was<br>able to see better agreement between data/simulation after the aperture adjustments <br>were made. JP/Vince suggested being cautious when adjusting the aperture cuts, as<br> the apertures should be well defined already. They suggested adjusting things that are<br> less well known first, such as the septum field. More details can be seen in her slides<br>[http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/09022015.pdf here].<br />
<br />
*Ryan<br />
**Working on generating physics quantities using models to eventually compare with data.<br>So far, he has incorporated the MAID2007 and Hall B models. He calculated the <br>hyperfine splitting quantities &Delta;1 and &Delta;2 using the Hall B EG1 model and compared them<br> to the results in C. Carlson's 2006 paper. His results agreed very well, he only saw a<br> small deviation for &Delta;2 in the lowest Q<sup>2</sup> range. To check that nothing strange was going <br> on in the low Q<sup>2</sup> range, he calculated &Delta;2 for various small ranges around zero, to ensure<br>that the integration method is well behaved. The Carlson paper also includes calculations <br>using the Simula model, he would like to do a check of this method as well, but is unsure <br>where to find the Simula model. Since he was able to reproduce the hyperfine splitting <br>result, he is confident in his calculation method; it should be straightforward to calculate <br>other spin structure function integrals. More details on his method can be found in his <br>slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_09215.pdf here].<br />
<br />
*Toby<br />
**Showed an update on his acceptance/scattering angle study. He applied cuts of varying<br>strictness on the reconstructed &theta; vs &phi; distribution at the target. He then calculated the <br>real scattering angle before/after scattering for each cut. Using these scattering angles <br> as inputs for the Bosted model he was able to calculate the XS and compare it to data.<br>He showed the comparison between data/Bosted model for each acceptance cut. He <br>hoped that the more extreme acceptance cuts on the data would flatten the yield <br>distribution, but it actually just enhanced the sawtooth pattern. JP questioned why the <br>Bosted prediction for one momentum bin (the green one) was so much lower than the<br> neighboring ones. Toby said the only input that goes into the model is the scattering angle,<br> so it must be considerably different for this momentum setting. He also commented that<br>the model prediction is scaled to match the data, so the scaling enhances the jump in<br>the model. More details on his acceptance cuts and method can be found in his slides<br>[http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/acceptance_scatangle.pdf here].<br />
<br />
<br />
==8/26/2015==<br />
<br />
Present: Jixie, Alex, Min, Kalyan, JP, Chao, Melissa <br><br />
By Phone: Vince, Jie, Ryan, Toby, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Chao<br />
**Gave an update on optics studies. Previously, he showed a comparison between optics data <br>and simulation where he cut on individual sieve holes. For this week, he included a cut on y <br>and dp that he didn't include previously. In the plot of &theta; vs y, JP pointed out that there were <br>additional tails on some sieve holes, Chao says these tails go away when the &phi; cut is <br>included. He showed a 2D plot of &theta; vs &phi;, along with the 1D projection of these variables. JP<br>commented that the data is more smeared out than the simulation, so it is difficult to compare <br>data with simulation results. It's possible that some of the smearing comes from events that <br>punch through the sieve slit and are not being cut out (the simulation currently assumes these <br>events are stopped by the sieve). Looking at the center hole, the data/simulation agree <br>reasonably well, but the agreement gets worse for holes on the edge of the sieve slit. Chao<br>will continue to look into this. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150826/Chao_WeeklyMeeting_08262015.pdf here].<br />
**He also mentioned that ~1 month ago he reported a problem with the [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150708/Chao_WeeklyMeeting_07082015.pdf BPM simulation].<br>He found it was actually a problem with the simulation itself, which has now been updated <br> to correct the problem.<br />
<br />
<br />
'''General Discussion:'''<br />
*Pengjia has submitted his BPM NIM paper.<br />
<br />
<br />
==8/19/2015==<br />
<br />
Present: Chao, Jie, Min, Jixie, Kalyan, Melissa <br><br />
By Phone: Vince, Ryan, Toby, Karl, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Showed a method for determining the correction to asymmetries for pion contamination. The <br>measured asymmetry can be written in terms of the electron and pion asymmetries, multiplied <br>by the fraction of events of that particle. To differentiate between electrons and pions, a cut is<br>made on events that trigger the Cherenkov detector (electrons) and events that do not trigger<br>the Cherenkov (pions). Kalyan commented that this method of selecting pions may be too blind,<br> and suggested making a 2D cut on E/p vs Cherenkov instead. To determine the fraction of<br>electrons/pions, "good event" cuts are applied (loose acceptance cuts, single track events and<br>pion rejector cuts) and the number of electrons/pions that survive the cuts are counted. Although<br>the pion asymmetry is much larger than the electron asymmetry, the number of residual pions<br>is very small, so the overall correction is small. For this example the 2.2 GeV, 5T longitudinal<br>setting was used, but the correction may be larger for the 5T transverse settings, which she <br>will do next. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Pion/PionAsym_08_19.pdf here].<br />
<br />
*Min <br />
**Gave an update on acceptance studies. She used the 1.7 GeV, 2.5T setting (with 3rd septum <br>configuration) to test the acceptance cuts using the yield ratio of data to simulation. She <br>showed a plot of target &theta; vs &phi; for both data and simulation, and applied a graphical cut to get<br>rid of events on the edges. Looking at the resulting 1D plots shows reasonable agreement<br>between &theta; and &phi;. Vince pointed out that there seems to be some additional structure in the<br>dp distribution, and suggested expanding the &delta; cut out to &pm; 4% to see if there is more <br>hidden structure. Min said she has seen this in other settings as well and will look into it. She<br>also tried adjusting the cuts on &theta;, &phi; and &delta; and looked at how the ratio of yields from data/<br>simulation changed; the ratio starts to drop off as the cuts get wider. Next she will work on<br>calculating the yields using W bins. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/08192015.pdf here].<br />
<br />
<br />
==8/12/2015==<br />
<br />
Present: Jie, Chao, Kalyan, Min, Jixie, Melissa <br><br />
By Phone: Pengjia, Ryan, Toby, Karl, Ellie, Alex <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Chao<br />
**Gave an update on optics studies. Previously, Min has shown comparisons of data/simulation<br> where she looked at different columns of sieve holes. Chao continued this study by cutting on <br>individual sieve holes. Looking at the center sieve hole, the &phi; distribution looks reasonable, but <br>the &theta; distribution has some issues. Specifically, the data is wider on the left side (negative &theta;) <br>than the simulation. He showed results for several sieve holes, including one that was in the <br>row as the center hole, but in the farthest column on the left side of the sieve slit. In this case <br>the &theta; distribution had similar width for both data and simulation, but the height of the simulation<br> distribution was larger. This may suggest that something is wrong with the acceptance in the <br>simulation. The problem with &theta; seems to be systematic; for most of the sieve holes there are <br>more events on the left side of the data than in the simulation. Kalyan asked whether the <br>thickness of the sieve slit was taken into account, Chao says it was included in the simulation <br>and optimizer. Jixie suggested comparing the dp distributions for each sieve hole. More details <br>can be seen in Chao's slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150812/Chao_WeeklyMeeting_08122015.pdf here].<br />
<br />
<br />
==7/29/2015==<br />
<br />
Present: Chao, Min, JP, Melissa <br><br />
By Phone: Alex, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Min<br />
**Gave an update on acceptance studies. Previously, Chao showed a correction for the beam<br>position in g2psim. Min checked this correction by looking at optics runs. On the data she <br>applied a cut on dp (to select elastic events) and on the focal plane (to get rid of junk <br> events). On the simulation, only an aperture cut was applied. She compared the data and<br>simulation results for &theta; and &phi; both before and after drifting from the sieve slit to the target.<br>The effect of the target field on &theta; is not very large, though there is a shift down in angle.<br>However, the shape of the &theta; distribution is different between data and simulation. The<br>effect of the target field on &phi; is significant; it's not clear why this is the case. To try to<br>determine the reason for the discrepancies, she applied a cut along each column of sieve<br>slit holes in &phi; and compared the data and simulation results for &theta;,&phi; and dp. Column 2<br>seems to have the best agreement (for dp), columns 1 and 2 have a shift while columns<br>3-6 have a difference in width. Chao suggested also cutting along each row of sieve slit<br>holes to better study the effect of the drift on &phi;. Min will work on identifying the differences<br>between data and simulation, specifically whether the boundaries are different between<br>the two. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07272015/07292015.pdf here].<br />
<br />
<br />
==7/22/2015==<br />
<br />
Present: JP, Min, Jixie, Melissa <br><br />
By Phone: Alex, Ryan, Toby, Ellie, Karl, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Showed various checks for packing fraction runs that have large discrepancies, including <br>beam position, beam energy, spectrometer central momentum setting, septum current, and<br>the location of anneals. For both the 2.2 and 1.1 GeV settings, there are significant shifts in <br>the x and y beam position (2mm or more). She showed the average and standard deviation <br> of epics readings for the LHRS septum current for each run. For several runs, there are small <br>number of epics readings that drift from the average current. It's not clear if this is the <br>current is actually changing or if it is a readout problem. She will look into the yield vs time<br>to try to determine this. JP suggested making a raster cut on the center of the beam to get<br> rid of any potential scraping. Pengjia says there is a way to cut on raster size, but there will<br> be an additional BPM uncertainty. Melissa will discuss this more offline with Pengjia. More<br>details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_07_22.pdf here].<br />
<br />
*Pengjia<br />
**Gave an update on calculating asymmetries/cross sections using the MAID model. This time, <br>he used the Bosted model to get the unpolarized cross sections for the proton. Using unradiated <br>cross section models, he still saw a factor of 6 difference when compared with data. Ryan also <br>calculated asymmetries using unradiated models, and the results were consistent with Pengjia's, <br>so it seems the radiative effects contribute significantly to the factor of 6 difference. More <br>details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07222015/MAID_update_20150722.pdf here].<br />
<br />
<br />
==7/15/2015==<br />
<br />
Present: JP, Min, Chao, Jixie, Melissa <br><br />
By Phone: Ryan, Toby, Ellie, Karl, Vince, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Chao<br />
**Doing a check of simulation/data results for the 2.2 GeV, longitudinal setting in order <br>to check that the optics calibration matrix will work for all momentum settings (not <br>just elastic). He showed a comparison for several different momentum settings.<br> Vince suggested simulating more events, since the statistics start to drop off for <br>lower momentum settings. In general, the data is broader then the result from<br>simulation. In the &theta; distribution, the "tails" seen in the data are not symmetric. JP<br> suggested carefully selecting cuts to remove any background from the data to <br>ensure a good comparison with simulation. More details can be seen in his <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150715/Chao_WeeklyMeeting_07152015.pdf here].<br />
<br />
*Pengjia<br />
**More discussion on Pengjia's [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07082015/MAID_update_20150708.pdf slides] from last week. Pengjia has seen a factor of <br>six difference between his asymmetry calculated from data compared to the <br>asymmetry determined using the MAID model. Ryan did not see this factor of six <br>in his study, but in addition to using radiated XS models, he is using a combination <br>of the Bosted and MAID models (Pengjia is using just the MAID model). Karl <br>commented that the XS from MAID is not very good for our kinematics. Pengjia <br>also showed an estimated NH3 XS. JP commented that it was surprising that the <br>delta peak wasn't visible. Pengjia will look into this for next time.<br />
<br />
<br />
==7/8/2015==<br />
<br />
Present: JP, Min, Chao, Melissa <br><br />
By Phone: Toby, Vince <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Pengjia<br />
**Working on comparing asymmetries determined from MAID to those calculated from <br>data; last time he showed a factor of 6 difference between the two results. This <br>time, he showed two different methods for calculating the differential XS from the <br>virtual photon XS. The first method calculates the differential XS directly from <br>the virtual photon XS, and the second method calculates the differential XS using <br>F<sub>1</sub>, F<sub>2</sub>, g<sub>1</sub> and g<sub>2</sub>. He also showed two different methods for calculating the <br>asymmetry from the virtual photon XS; one method uses A<sub>1</sub> and A<sub>2</sub>, while the other <br>is calculated from the virtual photon XS. There was a discrepancy between the two <br>methods, but he found that there was actually a mistake in one of the equations. <br>While the results from the two methods agree with each other, they are still a factor <br>of 6 larger than the results from data. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07082015/MAID_update_20150708.pdf here].<br />
<br />
*Toby<br />
**Showed an update of his scattering angle study for model reconstruction. He is <br>using BPM and optics data to determine the scattering angle. He showed an example <br>of the calculated scattering angle; JP questioned whether the range was really from <br>0-16 deg. Toby pointed out that there really aren't many events at the boundaries, <br>the distribution is peaked between 4.5-9 deg. He then uses this scattering angle as<br>input for the Bosted model. At low &nu; the simulation results match reasonably well<br>with the data, but the discrepancy starts to become larger as &nu; increases. He took <br>a closer look at the reconstructed scattering angle for each central momentum, and <br>found that a second peak is visible for smaller values of p0. If this second peak was <br>real, the simulation should recreate the data, so this could suggest a problem with <br>the reconstruction. However, Chao pointed out that, for this energy setting, the optics <br>calibration is not complete (currently using the longitudinal optics matrix), so the <br>reconstructed &theta; and &phi; may not be correct yet. For next time, Toby will test this <br>analysis using the 1.7 GeV setting, which has calibrated optics. More details can <br> be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/scatangle_talk.pdf here].<br />
<br />
*Melissa<br />
**Gave a summary of packing fraction analysis. For some settings, the variation in the <br>yields (and P<sub>f</sub>) is due to a fluctuation in the beam position. This will hopefully be<br>resolved by Jie's beam position/acceptance study. For the 2.2 GeV, 2.5T transverse setting<br> there is also an issue of a shift in &nu; between runs. For the 1.1 GeV, 2.5T transverse <br>setting, the yields vary depending on the beam current used for each run. JP suggested <br>a few things to check as the possible cause for these discrepancies including drift in the <br>BCM calibration, anneals of the target material, drift in field (HRS or septum), etc. She <br>has posted a technote draft [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Technotes/PF_technote_draft.pdf here], feedback would be appreciated. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_07_08.pdf here].<br />
<br />
*Min<br />
**Gave an update on her acceptance study. Last time, she showed that the simulation results <br>are more narrow than the data. For this time, she tried cutting on just the center hole, <br>and found that the dp distribution from data better matched the simulation. JP suggested <br>cutting on each of the different holes individually to determine which hole causes the dp <br>distribution to be wider. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07082015/07062015.pdf here].<br />
<br />
*Chao<br />
**Gave an update on optics analysis, currently checking whether simulation results match <br>with data, starting with optics data. First he checked whether the geometry was correct, <br>some deviation was found in the recent optics meeting. The position of the BPMs is hard-<br>coded into the simulation, and the drifting algorithm is used to drift the electrons <br>backward to the BPMs to simulate the readout of BPM A and B. He compared the &theta; <br>distribution before drifting in the target field using a fixed and non-fixed BPM location. <br>The results using a fixed BPM match well with the data. He is currently working on <br>checking this for all momentum settings, and will follow up with Pengjia about the BPM <br>problem. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150708/Chao_WeeklyMeeting_07082015.pdf here].<br />
<br />
<br />
==7/1/2015==<br />
<br />
Present: Chao, Vince, Jie, JP, Min, Melissa <br><br />
By Phone: Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Min<br />
**Gave an update on acceptance studies. She showed a summary table of each energy <br>setting and septum configuration. There hasn't been any problems in the 2.2 GeV, 5T <br>longitudinal and 1.7 GeV, 2.5T transverse settings, but some settings (2.2 GeV, 2.5T <br> transverse, 1.2 GeV, 2.5T transverse and 2.2 GeV, 5T transverse) have a discrepancy <br>in the focal plane between data and simulation. She compared the data divided by the <br>Mott XS to the simulation results without XS, and found that the simulation results <br>of &theta; and &phi; are narrower then the data. JP commented that, while including the Mott<br>XS might change the shape of the distribution, it shouldn't change the boundary. She <br>work on figuring out the cause for this discrepancy before calculating the acceptance. <br>More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07012015/07012015.pdf here].<br />
<br />
*Pengjia<br />
**Comparing asymmetries determined from the MAID model to those calculated from data.<br>Last time he showed a factor of 6 difference between the two results. He determined the <br>scattering angle and Q<sup>2</sup> by fitting the data and compared them to the quantities calculated <br>from MAID. He also showed the results of calculating the quantities g<sub>1</sub>, g<sub>2</sub>, F<sub>1</sub>, F<sub>2</sub>, A<sub>L</sub>, A<sub>T</sub>,<br> dXS<sub>L</sub>, dXS<sub>T</sub>, XS<sub>tot</sub> andXS<sub>mott</sub> using MAID. He hasn't included radiative corrections in his <br>calculations, but this probably won't account for the factor of 6. More details can be seen <br>in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07012015/MAID_20150701.pdf here].<br />
<br />
<br />
----<br />
<br />
==Jan-June 2015==<br />
[[Minutes_Jan2015_to_June2015]]<br />
----<br />
<br />
==July-Dec 2014==<br />
[[Minutes_July2014_to_Dec2014]]<br />
----<br />
<br />
==Jan-June 2014==<br />
[[Minutes_Jan2014_to_June2014]]<br />
----<br />
<br />
==June-Dec 2013==<br />
[[Minutes_June2013_to_Dec2013]]<br />
----<br />
<br />
==Jan-May 2013==<br />
[[Minutes_Jan2013_to_May2013]]<br />
----<br />
<br />
==April-Dec 2012==<br />
[[Minutes_Apr2012_to_Dec2012]]<br />
----<br />
<br />
==Jan-March 2012==<br />
[[Minutes_Jan2012_to_Mar2012]]<br />
----<br />
==July-Dec 2011==<br />
[[Minutes_July2011_to_Dec_2011]]<br />
----<br />
==Jan-June 2011==<br />
[[Minutes_Jan2011_to_June_2011]]<br />
----</div>Melissachttps://hallaweb.jlab.org/wiki/index.php?title=G2p_Weekly_Analysis&diff=26180G2p Weekly Analysis2015-10-28T13:27:34Z<p>Melissac: /* AGENDAS */</p>
<hr />
<div>Analysis meetings are held every Wednesday at 9:00 in F228. ([https://hallaweb.jlab.org/wiki/index.php/G2p_Analysis_Minutes Minutes])<br />
<br />
The conference phone number is 866-740-1260 (US) or 303-248-0285 (International). Access Code: 1466792<br />
<br />
Please edit the agenda to link to your talk prior to the start of the meeting. For help doing this, [https://hallaweb.jlab.org/wiki/index.php/Getting_Started_with_the_g2pWiki click here] <br />
<br />
Group members can post files at /u/group/halla/www/hallaweb/html/experiment/g2p/collaborators, <br><br />
which will then be accessible on the web from http://hallaweb.jlab.org/experiment/g2p/collaborators/<br />
<br />
=AGENDAS=<br />
<br />
'''Wednesday, October 28 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Asym/Asym_10_28.pdf Systematic Uncertainties] <br />
| Melissa<br />
|}<br />
<br />
<br />
'''Wednesday, October 14 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/slifer/2015/slifer_g2pcollab_101415.pdf Overview] <br />
| Karl<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/graduate_2015.pdf graduate] <br />
| Pengjia<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/talks/MCummings_CollabMeeting_20151013.pdf update] <br />
| Melissa<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/collaborationupdate.pdf dilution update/outlook] <br />
| Toby<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_10_09_simulation/2015_10_14_collaboration_meeting.pdf Update] <br />
| Jie<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/collab/10142015_collab_Min.pdf Update] <br />
| Min<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20151014/Chao_WeeklyMeeting_10142015.pdf Update] <br />
| Chao<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_101315.pdf Update] <br />
| Ryan<br />
|}<br />
<br />
<br />
'''Wednesday, September 30 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/diltalk_093015.pdf dilution update] <br />
| Toby<br />
|}<br />
<br />
<br />
'''Wednesday, September 23 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/09222015/asym_g12.pdf asymmetry] <br />
| Pengjia<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/09232015.pdf Acceptance Spectrum] <br />
| Min<br />
|}<br />
<br />
<br />
'''Wednesday, September 16 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_09_15_simulation/2015_09_15_Simulation_update.pdf simulation update] <br />
| jie<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_091615.pdf Model Calc. of Physics Quantities] <br />
| Ryan<br />
|}<br />
<br />
<br />
'''Wednesday, September 9 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_09_09_simulation_update/2015_09_09_Simulation%20update.pdf simulation update] <br />
| jie<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150909/Chao_WeeklyMeeting_09092015.pdf Optics Update] <br />
| Chao<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/09092015/asym_20150909.pdf asymmetry] <br />
| Pengjia<br />
|}<br />
<br />
<br />
'''Wednesday, September 2 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Pion/PionAsym_08_31.pdf Pion Asymmetries] <br />
| Melissa<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_09215.pdf Model Calc. of Physics Quantities] <br />
| Ryan<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/acceptance_scatangle.pdf Scattering Angle study contd.] <br />
| Toby<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/09022015.pdf Acceptance Tuning] <br />
| Min<br />
|}<br />
<br />
<br />
'''Wednesday, August 26 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150826/Chao_WeeklyMeeting_08262015.pdf Optics Update] <br />
| Chao<br />
|}<br />
<br />
<br />
'''Wednesday, August 19 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Pion/PionAsym_08_19.pdf Pion Asymmetries] <br />
| Melissa<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/08192015.pdf Acceptance Update] <br />
| Min<br />
|}<br />
<br />
<br />
'''Wednesday, August 12 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150812/Chao_WeeklyMeeting_08122015.pdf Optics Update] <br />
| Chao<br />
|}<br />
<br />
<br />
'''Wednesday, July 29 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07272015/07292015.pdf Acceptance - Optics run] <br />
| Min<br />
|}<br />
<br />
<br />
'''Wednesday, July 22 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_07_22.pdf Epics Checks for Pf Analysis] <br />
| Melissa<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07222015/MAID_update_20150722.pdf MAID update] <br />
| Pengjia<br />
|}<br />
<br />
<br />
'''Wednesday, July 15 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150715/Chao_WeeklyMeeting_07152015.pdf Optics Update] <br />
| Chao<br />
|}<br />
<br />
<br />
'''Wednesday, July 8 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07082015/MAID_update_20150708.pdf MAID update] <br />
| Pengjia<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/scatangle_talk.pdf model reconstruction - scattering angle study] <br />
| Toby<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_07_08.pdf Summary of Pf Analysis ] <br />
| Melissa<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07082015/07062015.pdf Dp Comparison ] <br />
| Min<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150708/Chao_WeeklyMeeting_07082015.pdf Optics Update] <br />
| Chao<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_07_05_plots/2015_07_06_Simulation_update.pdf Simulation Update] <br />
| Jie<br />
|}<br />
<br />
<br />
'''Wednesday, July 1 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07012015/07012015.pdf Acceptance Update] <br />
| Min<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07012015/MAID_20150701.pdf MAID asymmetry] <br />
| Pengjia<br />
|}<br />
<br />
<br />
'''Wednesday, June 24 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Technotes/PF_technote_draft.pdf PF Technote Draft] <br />
| Melissa<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/asymplots.pdf Asymmetry plots] <br />
| Toby<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_06_24_simulation/2015_06_25_Simulation_update.pdf simulation update] <br />
| Jie<br />
<br />
|}<br />
<br />
<br />
'''Wednesday, June 17 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_061715.pdf Pol Rad Corrections] <br />
| Ryan<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/anglecorrection.pdf Angle Correction to simulation] <br />
| Toby<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/06172015/06172015.pdf Acceptance Study - Dilution] <br />
| Min<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/Chao_WeeklyMeeting_06172015.pdf Optics Update] <br />
| Chao<br />
|}<br />
<br />
<br />
'''Wednesday, June 10 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_06_09_simulation/2015_06_10_Simulation_update.pdf Simulation update] <br />
| Jie<br />
|}<br />
<br />
<br />
'''Wednesday, May 27 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/05272015/maid_asym_20150527.pdf Asymmetries from MAID] <br />
| Pengjia<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/05272015/05272015.pdf Acceptance Update 3rd septum] <br />
| Min<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/05272015/Chao_WeeklyMeeting_05272015.pdf Optics Update] <br />
| Chao<br />
|}<br />
<br />
<br />
'''Wednesday, May 20 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/05202015/maid_asym.pdf Asymmetries from MAID] <br />
| Pengjia<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_05_20_snakefield/2015_05_20_hrsfield_update.pdf q1 and septum field] <br />
| Jie<br />
<br />
|}<br />
<br />
<br />
'''Wednesday, May 13 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_05_13_simu_rad_technotes/radiation_simulation_technotes.pdf energy-loss technotes] <br />
| Jie<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/dilutionnote.pdf dilution note] <br />
| Toby<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_05_13.pdf 1.1 GeV Elastic Yields] <br />
| Melissa<br />
|}<br />
<br />
<br />
'''Wednesday, May 6 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150506/Chao_WeeklyMeeting_05062015.pdf Optics Update] <br />
| Chao<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/05062015/05062015.pdf Acceptance Update] <br />
| Min<br />
|}<br />
<br />
<br />
'''Wednesday, April 29 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/04282015/Asymmetries%20for%20different%20raster%20cut.pdf Asymmetries for different raster cut] <br />
| Pengjia<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_04_29.pdf Pf Update] <br />
| Melissa<br />
|}<br />
<br />
<br />
'''Wednesday, April 22 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/technotes/bcm_technote.pdf BCM technote draft] <br />
| Pengjia<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/qualitychecktalk.pdf Quality check summary] <br />
| Toby<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150422/Chao_WeeklyMeeting_04222015.pdf Optics Update] <br />
| Chao<br />
|}<br />
<br />
<br />
'''Wednesday, April 15 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_04_15_acc/2015_04_15_Simulation_update.pdf SIMULATION Update] <br />
| Jie<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_04_15.pdf Pf Update] <br />
| Melissa<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_041515.pdf Rad Corrections] <br />
| Ryan<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/diltalk_041515.pdf Dilution Update] <br />
| Toby<br />
|}<br />
<br />
<br />
'''Wednesday, April 8 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150408/Chao_WeeklyMeeting_04082015.pdf Optics Update] <br />
| Chao<br />
|}<br />
<br />
<br />
'''Wednesday, April 1 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_04_01.pdf PF Update] <br />
| Melissa<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_040115.pdf Model Tune] <br />
| Ryan<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/04012015/04012015.pdf Acceptance Update] <br />
| Min<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_03_31_bpmpos/2015_03_31_Simulation_update.pdf Simulation Update] <br />
| Jie<br />
|}<br />
<br />
<br />
'''Wednesday, March 25 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_03_23_rad_effects/2015_03_25_Simulation_updae.pdf Simulation_update] <br />
| Jie<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/pf_dil_talk.pdf Dilution update] <br />
| Toby<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150325/Chao_WeeklyMeeting_03252015.pdf Optics Update] <br />
| Chao<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/03252015/asym_lr.pdf asymmetry] <br />
| Pengjia<br />
|}<br />
<br />
<br />
'''Wednesday, March 18 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_03_18.pdf Packing Fraction] <br />
| Melissa<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_031715.pdf Model Tune] <br />
| Ryan<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/03182015/03182015.pdf Acceptance Update] <br />
| Min<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/03112015/ Rastercut update] <br />
| Pengjia<br />
|}<br />
<br />
<br />
'''Wednesday, March 11 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_03_06_xs_ratio/2015_03_11_Simulation_updae.pdf simulation update] <br />
| Jie<br />
|}<br />
<br />
<br />
'''Wednesday, March 4 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/diltalk_030415.pdf dilution analysis] <br />
| Toby<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_030415.pdf Model Tune] <br />
| Ryan<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_03_04.pdf Packing Fraction] <br />
| Melissa<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/03042015/03042015.pdf Acceptance Update] <br />
| Min<br />
|}<br />
<br />
<br />
'''Wednesday, February 25 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_02_24_yields/Simulation_update_2015_02_24.pdf yields study] <br />
| Jie<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/technotes/Chao_TechNote_TargetField.pdf TN: Target Field Mapping TN Draft] <br />
| Chao<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/02252015/Position_Cut_20150225.pdf position cut for yields study] <br />
| Pengjia<br />
|}<br />
<br />
<br />
'''Wednesday, February 18 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/02182015/librastercut.pdf rastercut library(not available)] <br />
| Pengjia<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/02182015/02182015.pdf Acceptance Update] <br />
| Min<br />
|}<br />
<br />
<br />
'''Wednesday, February 11 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/dilution021015.pdf Dilution update] <br />
| Toby<br />
|}<br />
<br />
<br />
'''Wednesday, February 4 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Yields/Yields_02_03.pdf Run Quality Check - RHRS] <br />
| Melissa<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150204/Chao_WeeklyMeeting_02042015.pdf RHRS Optics Update] <br />
| Chao<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_02_04_radiative/2015_02_04_Simulation_updae.pdf Simulation update] <br />
| Jie<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/02042015/02042015.pdf Acceptance Update] <br />
| Min<br />
|}<br />
<br />
<br />
'''Wednesday, January 28 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_012815.pdf 1.157 GeV Run Quality Check] <br />
| Ryan<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/01282015/yield_drift_20150128.pdf run quality check] <br />
| Pengjia<br />
|}<br />
<br />
<br />
'''Wednesday, January 21 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Yields/Yields_01_21.pdf Data Quality Check for 2.2GeV, 2.5T] <br />
| Melissa<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150121/Chao_WeeklyMeeting_01212015.pdf RHRS Optics Update] <br />
| Chao<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/01212015/01212015.pdf Acceptance Update] <br />
| Min<br />
|}<br />
<br />
<br />
'''Wednesday, January 14 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/scaler_yield_drift_talk.pdf Yield Drift Study - Scalers] <br />
| Toby<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_011415.pdf 1.157 GeV Run Quality Check] <br />
| Ryan<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_01_12_dp/Simulation_update_2015_01_12.pdf dp] <br />
| Jie<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/01152015/data_quality_20150115.pdf 1.711 GeV run quality check] <br />
| Pengjia<br />
|}<br />
<br />
<br />
'''Wednesday, January 7 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/talks/MCummingsCollabMeeting_Jan.pdf Analysis Updates] <br />
| Melissa<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150107/Chao_WeeklyMeeting_01072015.pdf Optics Update] <br />
| Chao<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/CollabMeeting_12015.pdf Analysis Update] <br />
| Ryan<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/01072015/01072015.pdf Acceptance Update] <br />
| Min<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_01_06_pbosted/2015_01_06_Simulation_update.pdf simulation Update] <br />
| Jie<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/01.07.15.pdf dilution/quality check update] <br />
| Toby<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/01072015/false_asym_20150107.pdf false asymmetry] <br />
| Pengjia<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/slifer/2015/slifer_g2pcollab_010715.pdf Review]<br />
| Karl<br />
|}<br />
<br />
<br />
<br />
==2014==<br />
[[Slides_2014]]<br />
<br />
==2013==<br />
[[Slides_2013]]<br />
<br />
==2012==<br />
[[Slides_2012]]<br />
<br />
==2011==<br />
[[Slides_2011]]</div>Melissachttps://hallaweb.jlab.org/wiki/index.php?title=G2p_Analysis_Minutes&diff=26103G2p Analysis Minutes2015-10-15T13:21:12Z<p>Melissac: /* 10/14/2015 */</p>
<hr />
<div>Minutes of the weekly analysis meetings<br />
----<br />
[https://hallaweb.jlab.org/wiki/index.php/G2p_Weekly_Analysis Agenda]<br />
<br />
==10/14/2015==<br />
<br />
Present: JP, Min, Jixie, Kalyan, Melissa <br><br />
By Phone: Alexandre, Vince, Jie, Todd, Haiyan, Pengjia, Karl, Toby, Ryan, Xiaochao, Nilanga, Chao <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Karl<br />
**Went over the goals of the collaboration meeting:<br />
***Discuss physics topics for students graduating soon<br />
***Identify major remaining physics topics<br />
***Establish a policy for the release of plots<br />
**Suggested a policy for collaboration release of physics results, including specific requirements <br>for moving from "very preliminary" to "preliminary" to "final" results. Details can be seen in his <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/slifer/2015/slifer_g2pcollab_101415.pdf here], and they will be circulated to the g2p mailing list with some small modifications.<br />
<br />
*Pengjia<br />
**Will be defending next Wednesday (Oct. 21st). He showed a "very preliminary" physics <br> asymmetry for the 2.2 GeV 5T setting (both longitudinal and transverse) with a comparison to <br> a radiated model prediction. He used this result to extract a preliminary value for g1 and g2,<br>using the Bosted model as input for the cross section. This result does not include radiative<br>corrections. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/graduate_2015.pdf here].<br />
<br />
*Min<br />
**Showed an overview of status of acceptance study; the overall goal is to match the simulation<br>results to the data, so that the simulation can be used to calculate the acceptance. She<br>described the various attempts to correct the simulation results to match the data. Adjusting the<br> apertures based on optics data works well, but the other two methods (adjusting the apertures <br>based on dilution data and adjusting the acceptance cuts after removing the Mott XS from the <br>data) only work well around the target run. In addition, the simulated yield has a different shape <br>than the data, so the simulation must be adjusted to match this. She will go through this process <br>again once Chao is finished with the optics correction. She is planning to graduate next January, <br>and would like to include a cross section difference for one kinematic setting in her thesis. More <br>details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/collab/10142015_collab_Min.pdf here].<br />
<br />
*Melissa<br />
**Gave an overview of packing fraction analysis. Of the 5 total settings there are 3 that are reasonably <br>stable with some small drifts in yields, and 2 settings that have larger problems. During the 2.2 GeV, <br>2.5T setting the raster size was changed, which could possibly be corrected by applying a cut on<br>the center of the raster. The 1.1 GeV setting has large variations in the elastic yields; some of these <br>runs were taken at low currents (8-20nA), so the beam position information is not reliable. She also <br>showed the results of a pion asymmetry study. Although the pion asymmetry is very large, the <br>residual pion contamination after PID cuts are applied is very small, so the correction is not large. <br>She has scheduled her defense for December 4th, and would like to include a preliminary result <br>for g1,g2 in her thesis. To include a fully corrected result she will need preliminary radiative <br>corrections and dilution results, which she will work with Ryan and Toby to get. More details can <br>be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/talks/MCummings_CollabMeeting_20151013.pdf here].<br />
<br />
*Toby<br />
**Showed a preliminary dilution value that he had shown previously, and described several issues <br>with the result. These issues include that the model assumes a constant scattering angle, and does <br>not include some acceptance effects that are seen in the data. He has been working on correcting <br>these issues by incorporating a scattering angle from data into the model and applying acceptance <br>cuts to the data to remove acceptance effects. He showed the result of applying the acceptance cut <br>across all kinematics for the 5T longitudinal setting; including the acceptance cut gets rid of some of <br>the strange structure seen in the yields, such as the sawtooth pattern seen at high nu. The downside <br>of this method is that the acceptance cut causes a large loss in statistics. He is currently working on <br>trying to re-incorporate some of the lost statistics from the acceptance cut. More details can be seen <br>in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/collaborationupdate.pdf here].<br />
<br />
*Jie<br />
**Gave an update on his study using simulation to understand the drifts in yields. He looked at several <br>momentum settings in the 2.2 GeV, 2.5T setting that had variation in the yields. He varied the beam <br>position along the horizontal and vertical directions using both a point beam and rastered beam. He <br>generated a table summarizing the results using a Monte Carlo method, cross checking with averaged <br>acceptance. His results were similar to his previous test using only the Bosted model; some results <br>agree with what was seen in the data, some have the opposite sign. He will write up his method and <br>results in a technote. He is planning to graduate in summer of 2016. More details can be seen in his <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_10_09_simulation/2015_10_14_collaboration_meeting.pdf here].<br />
<br />
*Chao<br />
**Gave an update on optics analysis. Comparisons of simulation with data revealed that the <br>reconstructed kinematics have some offset. A correction was added to the reconstructed kinematics <br>(vs beam position) and he is currently working on merging this correction into the database with a <br>finely tuned fitting procedure. The problem is that the horizontal beam position shifts the dp <br>reconstruction. He showed the results of applying the new optics matrix which corrects for this shift. <br> He will apply this method to all kinematic settings and study the uncertainty of the optics. Once this <br>is done he will write a NIM paper for g2p optics. He plans to graduate in February/March and would <br>like to include the cross section difference for one or two settings with tuned acceptance and model <br>inputs to obtain a physics result. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20151014/Chao_WeeklyMeeting_10142015.pdf here].<br />
<br />
*Ryan<br />
**Since the last collaboration meeting he has improved the model tuning procedure by using an <br>automated procedure instead of tuning the model by hand. He has tested this using carbon data <br>from the UVa database and will run it for nitrogen data once he has updated saGDH N2 cross <br>sections from Vince. He also updated the systematic error study for inelastic unpolarized radiative <br>corrections by separating the integration/iteration error from the interpolation error. He has the <br>polarized radiative correction code running, and has completed a systematic uncertainty study on <br>the inelastic radiative corrections. He is also working on evaluating physics quantities using models, <br>specifically the hyperfine splitting calculation. He plans to graduate in summer/fall of 2016 and would <br>like to include full radiative corrections on g2p polarized cross sections in his thesis. More details can<br> be seen in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_101315.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*Important to do cross checks of results between students (ex. asymmetries)<br />
*Must be careful to include details of any physics results (whether radiative corrections are included,<br>dilution factor, model input instead of data, etc.)<br />
<br />
==9/30/2015==<br />
<br />
Present: JP, Kalyan, Jixie, Min <br><br />
By Phone: Pengjia, Toby, Ryan, Vince, Jie, Chao, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Toby<br />
**Showed an update on his acceptance/dilution study. He continued with the study of the cuts on the <br>reconstructed &theta; vs &phi; distribution at the target. He scanned several different &theta; vs &phi; cuts to see how <br>the acceptance effects the scattering angle and resulting yields. It turns out the small angle region is <br>influenced by the acceptance a lot but the center region gives a good agreement to the model. He <br>also loosed the center cut to &theta; ~ ± 40 mrad and &phi; ~ ± 10 mrad, the data still agreed with the model. <br>He then recalculated the dilution factor for 2.254 GeV longitudinal setting. More details on his <br>acceptance cuts and method can be found in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/diltalk_093015.pdf here].<br />
<br />
==9/23/2015==<br />
<br />
Present: JP, Kalyan, Min, Melissa <br><br />
By Phone: Pengjia, Toby, Ryan, Vince, Jie, Chao, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Pengjia<br />
**Showed the structure of his code to create a radiated model of the MAID and Bosted <br>models, based on Ryan's radiative correction work. He showed the breakdown of the <br>different components to the radiated model (internal, external and elastic tail). He used<br> the radiated model to calculate an asymmetry and cross section differences, which he <br> compared with data. Finally, he combined asymmetries calculated from data with the <br>Bosted model cross section to calculate a value for g1 and g2, which he compared <br>with values of g1/g2 determined using the MAID model. More details can be seen in <br>his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/09222015/asym_g12.pdf here].<br />
<br />
*Min<br />
**Gave an update on acceptance studies. Last time, she found that by adjusting the<br>apertures in the simulation she could match the data/simulation results for dp (for one <br>momentum setting). She tested this method for other momentum settings and found <br>that it did not work as well. She also showed a comparison of the yield spectrum for<br>helium runs in the 1.7 GeV setting; the shape of the two distributions are quite <br>different, which might suggest that the model deviates significantly form the data. In<br>the simulated results she saw several "bumps" in the yield, which correspond to the<br>location of resonances. She will update these results when the optics corrections are <br>complete. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/09232015.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*We would like to schedule another collaboration meeting in the near future. The <br>meeting is tentatively scheduled for Wednesday October 14th during our usual meeting <br>time (10am-12pm).<br />
*The purpose of the meeting is to:<br />
**Discuss student thesis topics (particularly any updates from the last <br>collaboration meeting)<br />
**Establish a procedure for presentation/release of collaboration plots/results<br />
*Each student should prepare a few slides (~5 minutes) to show analysis progress<br />
<br />
<br />
==9/16/2015==<br />
<br />
Present: Min, JP, Jixie, Melissa <br><br />
By Phone: Vince, Jie, Chao, Pengjia, Alex, Ryan, Toby, Ellie <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Jie<br />
**Gave an update on his simulation study using MUDIFI. Last time he showed that he uses a<br>least square fit to go from endplane to endplane. For the g2p simulation, it's used to go from<br>(x,y,&theta;,&phi;,dp) in the target plane to (x,y,&theta;,&phi;,dp) in the focal plane. SNAKE produces (x,y,&theta;,&phi;,dp)<br>data in both planes and a polynomial function can be used to determine the relationship<br>between the two planes. First the maximum power for each variable is determined, symmetries<br>are included (if applicable), then the priority of each function must be determined. A Gram-<br>Schmidt transformation is used to do the minimization, and the final step is to decide whether<br>to accept the function f<sub>i</sub>. JP/Vince asked how the priority for each function is chosen, since the<br>choice could introduce some ordering dependence. Since we don't have enough data to<br>constrain, JP suggested introducing some physics. He also suggested getting rid of dp in the<br>focal plane (since it is really just dp in the target plane) so that there is one less dimension to<br>fit. More details can be seen in Jie's slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_09_15_simulation/2015_09_15_Simulation_update.pdf here].<br />
<br />
*Ryan<br />
**Gave an update on evaluating physics quantities using models. His goal was to do a<br>comparison of the hyperfine splitting calculation in C. Carlson's 2006/2008 paper using MAID<br>and Hall B models. Previously he showed a comparison using the Hall B model, where he saw<br>good agreement between his calculation and Carlson's result. For this time he also did a<br>comparison using the MAID model. There is a large difference between the two models for the<br>value of the integrand of &Delta;<sub>2</sub>, over the full range of Q<sup>2</sup>. JP suggested comparing the value of g2<br>between the two models, instead of &Delta;<sub>2</sub>. More details can be seen in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_091615.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*Toby<br />
**Last time he showed a comparison between data and cross sections calculated using the<br>Bosted model (seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/acceptance_scatangle.pdf here]). The model was not continuous for one momentum setting. It <br>turns out the BPM was not recording for that setting, so he re-calculated the XS using<br>values for &theta; and &phi; from surrounding runs and found that the result was now consistent with<br>the neighboring momentum settings. He also played around with the acceptance cuts he<br>showed, and found a region using the "extreme cut" where the sawtooth pattern go away<br>and the yields become flat.<br />
<br />
<br />
==9/9/2015==<br />
<br />
Present: Min, JP, Jixie, Melissa <br><br />
By Phone: Vince, Jie, Chao, Ryan, Toby, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Jie<br />
**Gave an overview of his simulation study using SNAKE and MUDIFI. Using SNAKE, the<br>idea is to trace the particle trajectory in a series of free boxes, then an endplane can be<br>defined within the free boxes to determine the trajectory from endplane to endplane. In<br>g2psim this will be used to trace the trajectory between the sieve plane and the focal<br>plane. There are two important issues to consider, the magnetic field in the free boxes,<br>and the transportation method between the two endplanes. A Runge-Kutta method is <br>used for the transportation, and an adaptive method (which changes with field size and<br>gradient) is used to determine the step size. For the magnetic field, a 3D Tosca field<br>map is used for the septum, and an analytic model is used for the spectrometer magnets. <br> He also described the method for choosing the transportation function to determine the <br>25 matrix terms for each kinematic variable (up to 4th order). JP asked how to determine <br>which order is more important, and cautioned to be careful not to over fit the data. He and<br>Jie will discuss this more offline. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_09_09_simulation_update/2015_09_09_Simulation%20update.pdf here].<br />
<br />
*Chao<br />
**Gave an optics status update. The current problem is that changes in the horizontal beam<br>position changes the dp reconstruction. This was fixed by applying a linear correction in<br>BPM-x and BPM-y to &theta;, &phi; and dp. Applying this correction made the data/simulation <br>agree, but it is still necessary to understand the correction. Using dp scan data with beam<br>position scan data still leaves an offset in &theta; and &phi;. He also tried two other methods to do<br>the calibration. Method 1 uses the central hole to determine a constant offset, uses the<br>horizontal beam position scan data to determine all the matrix elements related to y, and<br>uses dp scan runs to fit the additional matrix elements. Method 2 uses beam position<br>scan data to determine the matrix elements that are not related to x<sub>fp</sub>. Neither of these<br>methods works very well, even when the fitting order of the matrix elements are adjusted.<br>He will continue to check more fitting procedures. More details can be found in his slides <br>[http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150909/Chao_WeeklyMeeting_09092015.pdf here].<br />
<br />
*Pengjia<br />
**Gave an update on comparing asymmetries from data/models for the 2.2 GeV, 5T <br>longitudinal setting. He first radiated the Bosted model XS; he showed the break down of<br>the different radiative corrections including the elastic tail (internal and external) and the<br>radiative effects from inelastic scattering. He showed a comparison with Ryan's results<br>which had good agreement, though there is some deviation when he used different proton<br>form factors (provided by Moshe). In order to compare the asymmetry result with data, he<br>needs to do the radiative corrections for the polarized MAID model, which he will continue<br>to work on. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/09092015/asym_20150909.pdf here].<br />
<br />
<br />
==9/2/2015==<br />
<br />
Present: JP, Min, Kalyan, Melissa <br><br />
By Phone: Vince, Alex, Jie, Chao, Ryan, Toby, Ellie, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Gave an update on determining the correction to asymmetries for pion contamination. <br>Previously, she used the 2.2 GeV, 5T longitudinal setting as an example, for this time <br>she used the transverse configuration, as it has the largest pion contamination. She <br>modified her method for differentiating between electrons and pions; previously she <br>identified pions as events that do not trigger the Cherenkov, this time she used a cut <br>below the single photo electron peak to select pions. JP suggested using stricter cuts <br>for selecting pions when determining the pion asymmetry, to make sure it is a clean <br>sample. Although this setting has a large pion contamination, the number of pion<br> events that remain after lead glass cuts are applied is low, so the overall correction <br>is very small. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Pion/PionAsym_08_31.pdf here].<br />
<br />
*Min<br />
**Gave an update on acceptance tuning. She looked at results from the 1.7 GeV setting <br>and found that the height of the peaks is different between data and simulation for <br>different holes in the sieve slit. Looking at the &theta; vs &phi; distribution, she noticed on the<br>positive &theta; side there were fewer holes in simulation than in data, and on the negative <br> &theta; side there were more holes in simulation compared to data. She tried adjusting the<br>aperture cuts by changing the physical location of the Q1, Q2 and septum planes to <br>uncover events that were previously blocked. After the adjustment, the data/simulation <br>results agreed much better. She showed a similar procedure for a dilution run and was<br>able to see better agreement between data/simulation after the aperture adjustments <br>were made. JP/Vince suggested being cautious when adjusting the aperture cuts, as<br> the apertures should be well defined already. They suggested adjusting things that are<br> less well known first, such as the septum field. More details can be seen in her slides<br>[http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/09022015.pdf here].<br />
<br />
*Ryan<br />
**Working on generating physics quantities using models to eventually compare with data.<br>So far, he has incorporated the MAID2007 and Hall B models. He calculated the <br>hyperfine splitting quantities &Delta;1 and &Delta;2 using the Hall B EG1 model and compared them<br> to the results in C. Carlson's 2006 paper. His results agreed very well, he only saw a<br> small deviation for &Delta;2 in the lowest Q<sup>2</sup> range. To check that nothing strange was going <br> on in the low Q<sup>2</sup> range, he calculated &Delta;2 for various small ranges around zero, to ensure<br>that the integration method is well behaved. The Carlson paper also includes calculations <br>using the Simula model, he would like to do a check of this method as well, but is unsure <br>where to find the Simula model. Since he was able to reproduce the hyperfine splitting <br>result, he is confident in his calculation method; it should be straightforward to calculate <br>other spin structure function integrals. More details on his method can be found in his <br>slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_09215.pdf here].<br />
<br />
*Toby<br />
**Showed an update on his acceptance/scattering angle study. He applied cuts of varying<br>strictness on the reconstructed &theta; vs &phi; distribution at the target. He then calculated the <br>real scattering angle before/after scattering for each cut. Using these scattering angles <br> as inputs for the Bosted model he was able to calculate the XS and compare it to data.<br>He showed the comparison between data/Bosted model for each acceptance cut. He <br>hoped that the more extreme acceptance cuts on the data would flatten the yield <br>distribution, but it actually just enhanced the sawtooth pattern. JP questioned why the <br>Bosted prediction for one momentum bin (the green one) was so much lower than the<br> neighboring ones. Toby said the only input that goes into the model is the scattering angle,<br> so it must be considerably different for this momentum setting. He also commented that<br>the model prediction is scaled to match the data, so the scaling enhances the jump in<br>the model. More details on his acceptance cuts and method can be found in his slides<br>[http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/acceptance_scatangle.pdf here].<br />
<br />
<br />
==8/26/2015==<br />
<br />
Present: Jixie, Alex, Min, Kalyan, JP, Chao, Melissa <br><br />
By Phone: Vince, Jie, Ryan, Toby, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Chao<br />
**Gave an update on optics studies. Previously, he showed a comparison between optics data <br>and simulation where he cut on individual sieve holes. For this week, he included a cut on y <br>and dp that he didn't include previously. In the plot of &theta; vs y, JP pointed out that there were <br>additional tails on some sieve holes, Chao says these tails go away when the &phi; cut is <br>included. He showed a 2D plot of &theta; vs &phi;, along with the 1D projection of these variables. JP<br>commented that the data is more smeared out than the simulation, so it is difficult to compare <br>data with simulation results. It's possible that some of the smearing comes from events that <br>punch through the sieve slit and are not being cut out (the simulation currently assumes these <br>events are stopped by the sieve). Looking at the center hole, the data/simulation agree <br>reasonably well, but the agreement gets worse for holes on the edge of the sieve slit. Chao<br>will continue to look into this. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150826/Chao_WeeklyMeeting_08262015.pdf here].<br />
**He also mentioned that ~1 month ago he reported a problem with the [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150708/Chao_WeeklyMeeting_07082015.pdf BPM simulation].<br>He found it was actually a problem with the simulation itself, which has now been updated <br> to correct the problem.<br />
<br />
<br />
'''General Discussion:'''<br />
*Pengjia has submitted his BPM NIM paper.<br />
<br />
<br />
==8/19/2015==<br />
<br />
Present: Chao, Jie, Min, Jixie, Kalyan, Melissa <br><br />
By Phone: Vince, Ryan, Toby, Karl, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Showed a method for determining the correction to asymmetries for pion contamination. The <br>measured asymmetry can be written in terms of the electron and pion asymmetries, multiplied <br>by the fraction of events of that particle. To differentiate between electrons and pions, a cut is<br>made on events that trigger the Cherenkov detector (electrons) and events that do not trigger<br>the Cherenkov (pions). Kalyan commented that this method of selecting pions may be too blind,<br> and suggested making a 2D cut on E/p vs Cherenkov instead. To determine the fraction of<br>electrons/pions, "good event" cuts are applied (loose acceptance cuts, single track events and<br>pion rejector cuts) and the number of electrons/pions that survive the cuts are counted. Although<br>the pion asymmetry is much larger than the electron asymmetry, the number of residual pions<br>is very small, so the overall correction is small. For this example the 2.2 GeV, 5T longitudinal<br>setting was used, but the correction may be larger for the 5T transverse settings, which she <br>will do next. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Pion/PionAsym_08_19.pdf here].<br />
<br />
*Min <br />
**Gave an update on acceptance studies. She used the 1.7 GeV, 2.5T setting (with 3rd septum <br>configuration) to test the acceptance cuts using the yield ratio of data to simulation. She <br>showed a plot of target &theta; vs &phi; for both data and simulation, and applied a graphical cut to get<br>rid of events on the edges. Looking at the resulting 1D plots shows reasonable agreement<br>between &theta; and &phi;. Vince pointed out that there seems to be some additional structure in the<br>dp distribution, and suggested expanding the &delta; cut out to &pm; 4% to see if there is more <br>hidden structure. Min said she has seen this in other settings as well and will look into it. She<br>also tried adjusting the cuts on &theta;, &phi; and &delta; and looked at how the ratio of yields from data/<br>simulation changed; the ratio starts to drop off as the cuts get wider. Next she will work on<br>calculating the yields using W bins. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/08192015.pdf here].<br />
<br />
<br />
==8/12/2015==<br />
<br />
Present: Jie, Chao, Kalyan, Min, Jixie, Melissa <br><br />
By Phone: Pengjia, Ryan, Toby, Karl, Ellie, Alex <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Chao<br />
**Gave an update on optics studies. Previously, Min has shown comparisons of data/simulation<br> where she looked at different columns of sieve holes. Chao continued this study by cutting on <br>individual sieve holes. Looking at the center sieve hole, the &phi; distribution looks reasonable, but <br>the &theta; distribution has some issues. Specifically, the data is wider on the left side (negative &theta;) <br>than the simulation. He showed results for several sieve holes, including one that was in the <br>row as the center hole, but in the farthest column on the left side of the sieve slit. In this case <br>the &theta; distribution had similar width for both data and simulation, but the height of the simulation<br> distribution was larger. This may suggest that something is wrong with the acceptance in the <br>simulation. The problem with &theta; seems to be systematic; for most of the sieve holes there are <br>more events on the left side of the data than in the simulation. Kalyan asked whether the <br>thickness of the sieve slit was taken into account, Chao says it was included in the simulation <br>and optimizer. Jixie suggested comparing the dp distributions for each sieve hole. More details <br>can be seen in Chao's slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150812/Chao_WeeklyMeeting_08122015.pdf here].<br />
<br />
<br />
==7/29/2015==<br />
<br />
Present: Chao, Min, JP, Melissa <br><br />
By Phone: Alex, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Min<br />
**Gave an update on acceptance studies. Previously, Chao showed a correction for the beam<br>position in g2psim. Min checked this correction by looking at optics runs. On the data she <br>applied a cut on dp (to select elastic events) and on the focal plane (to get rid of junk <br> events). On the simulation, only an aperture cut was applied. She compared the data and<br>simulation results for &theta; and &phi; both before and after drifting from the sieve slit to the target.<br>The effect of the target field on &theta; is not very large, though there is a shift down in angle.<br>However, the shape of the &theta; distribution is different between data and simulation. The<br>effect of the target field on &phi; is significant; it's not clear why this is the case. To try to<br>determine the reason for the discrepancies, she applied a cut along each column of sieve<br>slit holes in &phi; and compared the data and simulation results for &theta;,&phi; and dp. Column 2<br>seems to have the best agreement (for dp), columns 1 and 2 have a shift while columns<br>3-6 have a difference in width. Chao suggested also cutting along each row of sieve slit<br>holes to better study the effect of the drift on &phi;. Min will work on identifying the differences<br>between data and simulation, specifically whether the boundaries are different between<br>the two. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07272015/07292015.pdf here].<br />
<br />
<br />
==7/22/2015==<br />
<br />
Present: JP, Min, Jixie, Melissa <br><br />
By Phone: Alex, Ryan, Toby, Ellie, Karl, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Showed various checks for packing fraction runs that have large discrepancies, including <br>beam position, beam energy, spectrometer central momentum setting, septum current, and<br>the location of anneals. For both the 2.2 and 1.1 GeV settings, there are significant shifts in <br>the x and y beam position (2mm or more). She showed the average and standard deviation <br> of epics readings for the LHRS septum current for each run. For several runs, there are small <br>number of epics readings that drift from the average current. It's not clear if this is the <br>current is actually changing or if it is a readout problem. She will look into the yield vs time<br>to try to determine this. JP suggested making a raster cut on the center of the beam to get<br> rid of any potential scraping. Pengjia says there is a way to cut on raster size, but there will<br> be an additional BPM uncertainty. Melissa will discuss this more offline with Pengjia. More<br>details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_07_22.pdf here].<br />
<br />
*Pengjia<br />
**Gave an update on calculating asymmetries/cross sections using the MAID model. This time, <br>he used the Bosted model to get the unpolarized cross sections for the proton. Using unradiated <br>cross section models, he still saw a factor of 6 difference when compared with data. Ryan also <br>calculated asymmetries using unradiated models, and the results were consistent with Pengjia's, <br>so it seems the radiative effects contribute significantly to the factor of 6 difference. More <br>details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07222015/MAID_update_20150722.pdf here].<br />
<br />
<br />
==7/15/2015==<br />
<br />
Present: JP, Min, Chao, Jixie, Melissa <br><br />
By Phone: Ryan, Toby, Ellie, Karl, Vince, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Chao<br />
**Doing a check of simulation/data results for the 2.2 GeV, longitudinal setting in order <br>to check that the optics calibration matrix will work for all momentum settings (not <br>just elastic). He showed a comparison for several different momentum settings.<br> Vince suggested simulating more events, since the statistics start to drop off for <br>lower momentum settings. In general, the data is broader then the result from<br>simulation. In the &theta; distribution, the "tails" seen in the data are not symmetric. JP<br> suggested carefully selecting cuts to remove any background from the data to <br>ensure a good comparison with simulation. More details can be seen in his <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150715/Chao_WeeklyMeeting_07152015.pdf here].<br />
<br />
*Pengjia<br />
**More discussion on Pengjia's [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07082015/MAID_update_20150708.pdf slides] from last week. Pengjia has seen a factor of <br>six difference between his asymmetry calculated from data compared to the <br>asymmetry determined using the MAID model. Ryan did not see this factor of six <br>in his study, but in addition to using radiated XS models, he is using a combination <br>of the Bosted and MAID models (Pengjia is using just the MAID model). Karl <br>commented that the XS from MAID is not very good for our kinematics. Pengjia <br>also showed an estimated NH3 XS. JP commented that it was surprising that the <br>delta peak wasn't visible. Pengjia will look into this for next time.<br />
<br />
<br />
==7/8/2015==<br />
<br />
Present: JP, Min, Chao, Melissa <br><br />
By Phone: Toby, Vince <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Pengjia<br />
**Working on comparing asymmetries determined from MAID to those calculated from <br>data; last time he showed a factor of 6 difference between the two results. This <br>time, he showed two different methods for calculating the differential XS from the <br>virtual photon XS. The first method calculates the differential XS directly from <br>the virtual photon XS, and the second method calculates the differential XS using <br>F<sub>1</sub>, F<sub>2</sub>, g<sub>1</sub> and g<sub>2</sub>. He also showed two different methods for calculating the <br>asymmetry from the virtual photon XS; one method uses A<sub>1</sub> and A<sub>2</sub>, while the other <br>is calculated from the virtual photon XS. There was a discrepancy between the two <br>methods, but he found that there was actually a mistake in one of the equations. <br>While the results from the two methods agree with each other, they are still a factor <br>of 6 larger than the results from data. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07082015/MAID_update_20150708.pdf here].<br />
<br />
*Toby<br />
**Showed an update of his scattering angle study for model reconstruction. He is <br>using BPM and optics data to determine the scattering angle. He showed an example <br>of the calculated scattering angle; JP questioned whether the range was really from <br>0-16 deg. Toby pointed out that there really aren't many events at the boundaries, <br>the distribution is peaked between 4.5-9 deg. He then uses this scattering angle as<br>input for the Bosted model. At low &nu; the simulation results match reasonably well<br>with the data, but the discrepancy starts to become larger as &nu; increases. He took <br>a closer look at the reconstructed scattering angle for each central momentum, and <br>found that a second peak is visible for smaller values of p0. If this second peak was <br>real, the simulation should recreate the data, so this could suggest a problem with <br>the reconstruction. However, Chao pointed out that, for this energy setting, the optics <br>calibration is not complete (currently using the longitudinal optics matrix), so the <br>reconstructed &theta; and &phi; may not be correct yet. For next time, Toby will test this <br>analysis using the 1.7 GeV setting, which has calibrated optics. More details can <br> be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/scatangle_talk.pdf here].<br />
<br />
*Melissa<br />
**Gave a summary of packing fraction analysis. For some settings, the variation in the <br>yields (and P<sub>f</sub>) is due to a fluctuation in the beam position. This will hopefully be<br>resolved by Jie's beam position/acceptance study. For the 2.2 GeV, 2.5T transverse setting<br> there is also an issue of a shift in &nu; between runs. For the 1.1 GeV, 2.5T transverse <br>setting, the yields vary depending on the beam current used for each run. JP suggested <br>a few things to check as the possible cause for these discrepancies including drift in the <br>BCM calibration, anneals of the target material, drift in field (HRS or septum), etc. She <br>has posted a technote draft [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Technotes/PF_technote_draft.pdf here], feedback would be appreciated. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_07_08.pdf here].<br />
<br />
*Min<br />
**Gave an update on her acceptance study. Last time, she showed that the simulation results <br>are more narrow than the data. For this time, she tried cutting on just the center hole, <br>and found that the dp distribution from data better matched the simulation. JP suggested <br>cutting on each of the different holes individually to determine which hole causes the dp <br>distribution to be wider. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07082015/07062015.pdf here].<br />
<br />
*Chao<br />
**Gave an update on optics analysis, currently checking whether simulation results match <br>with data, starting with optics data. First he checked whether the geometry was correct, <br>some deviation was found in the recent optics meeting. The position of the BPMs is hard-<br>coded into the simulation, and the drifting algorithm is used to drift the electrons <br>backward to the BPMs to simulate the readout of BPM A and B. He compared the &theta; <br>distribution before drifting in the target field using a fixed and non-fixed BPM location. <br>The results using a fixed BPM match well with the data. He is currently working on <br>checking this for all momentum settings, and will follow up with Pengjia about the BPM <br>problem. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150708/Chao_WeeklyMeeting_07082015.pdf here].<br />
<br />
<br />
==7/1/2015==<br />
<br />
Present: Chao, Vince, Jie, JP, Min, Melissa <br><br />
By Phone: Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Min<br />
**Gave an update on acceptance studies. She showed a summary table of each energy <br>setting and septum configuration. There hasn't been any problems in the 2.2 GeV, 5T <br>longitudinal and 1.7 GeV, 2.5T transverse settings, but some settings (2.2 GeV, 2.5T <br> transverse, 1.2 GeV, 2.5T transverse and 2.2 GeV, 5T transverse) have a discrepancy <br>in the focal plane between data and simulation. She compared the data divided by the <br>Mott XS to the simulation results without XS, and found that the simulation results <br>of &theta; and &phi; are narrower then the data. JP commented that, while including the Mott<br>XS might change the shape of the distribution, it shouldn't change the boundary. She <br>work on figuring out the cause for this discrepancy before calculating the acceptance. <br>More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07012015/07012015.pdf here].<br />
<br />
*Pengjia<br />
**Comparing asymmetries determined from the MAID model to those calculated from data.<br>Last time he showed a factor of 6 difference between the two results. He determined the <br>scattering angle and Q<sup>2</sup> by fitting the data and compared them to the quantities calculated <br>from MAID. He also showed the results of calculating the quantities g<sub>1</sub>, g<sub>2</sub>, F<sub>1</sub>, F<sub>2</sub>, A<sub>L</sub>, A<sub>T</sub>,<br> dXS<sub>L</sub>, dXS<sub>T</sub>, XS<sub>tot</sub> andXS<sub>mott</sub> using MAID. He hasn't included radiative corrections in his <br>calculations, but this probably won't account for the factor of 6. More details can be seen <br>in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07012015/MAID_20150701.pdf here].<br />
<br />
<br />
----<br />
<br />
==Jan-June 2015==<br />
[[Minutes_Jan2015_to_June2015]]<br />
----<br />
<br />
==July-Dec 2014==<br />
[[Minutes_July2014_to_Dec2014]]<br />
----<br />
<br />
==Jan-June 2014==<br />
[[Minutes_Jan2014_to_June2014]]<br />
----<br />
<br />
==June-Dec 2013==<br />
[[Minutes_June2013_to_Dec2013]]<br />
----<br />
<br />
==Jan-May 2013==<br />
[[Minutes_Jan2013_to_May2013]]<br />
----<br />
<br />
==April-Dec 2012==<br />
[[Minutes_Apr2012_to_Dec2012]]<br />
----<br />
<br />
==Jan-March 2012==<br />
[[Minutes_Jan2012_to_Mar2012]]<br />
----<br />
==July-Dec 2011==<br />
[[Minutes_July2011_to_Dec_2011]]<br />
----<br />
==Jan-June 2011==<br />
[[Minutes_Jan2011_to_June_2011]]<br />
----</div>Melissachttps://hallaweb.jlab.org/wiki/index.php?title=G2p_Analysis_Minutes&diff=26096G2p Analysis Minutes2015-10-14T21:31:33Z<p>Melissac: /* 10/14/2015 */</p>
<hr />
<div>Minutes of the weekly analysis meetings<br />
----<br />
[https://hallaweb.jlab.org/wiki/index.php/G2p_Weekly_Analysis Agenda]<br />
<br />
==10/14/2015==<br />
<br />
Present: JP, Min, Jixie, Kalyan, Melissa <br><br />
By Phone: Alexandre, Vince, Jie, Todd, Haiyan, Pengjia, Karl, Toby, Ryan, Xiaochao, Nilanga, Chao <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Karl<br />
**Went over the goals of the collaboration meeting:<br />
***Discuss physics topics for students graduating soon<br />
***Identify major remaining physics topics<br />
***Establish a policy for the release of plots<br />
**Suggested a policy for collaboration release of physics results, including specific requirements <br>for moving from "very preliminary" to "preliminary" to "final" results. Details can be seen in his <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/slifer/2015/slifer_g2pcollab_101415.pdf here], and they will be circulated to the g2p mailing list with some small modifications.<br />
<br />
*Pengjia<br />
**Will be defending next Wednesday (Oct. 21st). He showed a "very preliminary" physics <br> asymmetry for the 2.2 GeV 5T setting (both longitudinal and transverse) with a comparison to <br> a radiated model prediction. He used this result to extract a preliminary value for g1 and g2,<br>using the Bosted model as input for the cross section. This result does not include radiative<br>corrections. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/graduate_2015.pdf here].<br />
<br />
*Min<br />
**Showed an overview of status of acceptance study; the overall goal is to match the simulation<br>results to the data, so that the simulation can be used to calculate the acceptance. She<br>described the various attempts to correct the simulation results to match the data. Adjusting the<br> apertures based on optics data works well, but the other two methods (adjusting the apertures <br>based on dilution data and adjusting the acceptance cuts after removing the Mott XS from the <br>data) only work well around the target run. In addition, the simulated yield has a different shape <br>than the data, so the simulation must be adjusted to match this. She will go through this process <br>again once Chao is finished with the optics correction. She is planning to graduate next January, <br>and would like to include a cross section difference for one kinematic setting in her thesis. More <br>details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/collab/10142015_collab_Min.pdf here].<br />
<br />
*Melissa<br />
**Gave an overview of packing fraction analysis. Of the 5 total settings there are 3 that are reasonably <br>stable with some small drifts in yields, and 2 settings that have larger problems. During the 2.2 GeV, <br>2.5T setting the raster size was changed, which could possibly be corrected by applying a cut on<br>the center of the raster. The 1.1 GeV setting has large variations in the elastic yields; some of these <br>runs were taken at low currents (8-20nA), so the beam position information is not reliable. She also <br>showed the results of a pion asymmetry study. Although the pion asymmetry is very large, the <br>residual pion contamination after PID cuts are applied is very small, so the correction is not large. <br>She has scheduled her defense for December 4th, and would like to include a preliminary result <br>for g1,g2 in her thesis. To include a fully corrected result she will need preliminary radiative <br>corrections and dilution results, which she will work with Ryan and Toby to get. More details can <br>be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/talks/MCummings_CollabMeeting_20151013.pdf here].<br />
<br />
*Toby<br />
**Showed a preliminary dilution value that he had shown previously, and described several issues <br>with the result. These issues include that the model assumes a constant scattering angle, and does <br>not include some acceptance effects that are seen in the data. He has been working on correcting <br>these issues by incorporating a scattering angle from data into the model and applying acceptance <br>cuts to the data to remove acceptance effects. He showed the result of applying the acceptance cut <br>across all kinematics for the 5T longitudinal setting; including the acceptance cut gets rid of some of <br>the strange structure seen in the yields, such as the sawtooth pattern seen at high nu. The downside <br>of this method is that the acceptance cut causes a large loss in statistics. He is currently working on <br>trying to re-incorporate some of the lost statistics from the acceptance cut. More details can be seen <br>in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/collaborationupdate.pdf here].<br />
<br />
*Jie<br />
**Gave an update on his study using simulation to understand the drifts in yields. He looked at several <br>momentum settings in the 2.2 GeV, 2.5T setting that had variation in the yields. He varied the beam <br>position along the horizontal and vertical directions using both a point beam and rastered beam. He <br>generated a table summarizing the results using a Monte Carlo method, cross checking with averaged <br>acceptance. His results were similar to his previous test using only the Bosted model; some results <br>agree with what was seen in the data, some have the opposite sign. He will write up his method and <br>results in a technote. He is planning to graduate in summer of 2016. More details can be seen in his <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_10_09_simulation/2015_10_14_collaboration_meeting.pdf here].<br />
<br />
*Chao<br />
**Gave an update on optics analysis. Comparisons of simulation with data revealed that the <br>reconstructed kinematics have some offset. A correction was added to the reconstructed kinematics <br>(vs beam position) and he is currently working on merging this correction into the database with a <br>finely tuned fitting procedure. The problem is that the horizontal beam position shifts the dp <br>reconstruction. He showed the results of applying the new optics matrix which corrects for this shift. <br> He will apply this method to all kinematic settings and study the uncertainty of the optics. Once this <br>is done he will write a NIM paper for g2p optics. He plans to graduate in February/March and would <br>like to include the cross section difference for one or two settings with tuned acceptance and model <br>inputs to obtain a physics result. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20151014/Chao_WeeklyMeeting_10142015.pdf here].<br />
<br />
*Ryan<br />
**Since the last collaboration meeting he has improved the model tuning procedure by using an automated <br>procedure instead of tuning the model by hand. He has tested this using carbon data from the UVa database <br>and will run it for nitrogen data once he has updated saGDH N2 cross sections from Vince. He also updated <br>the systematic error study for inelastic unpolarized radiative corrections by separating the integration/<br>iteration error from the interpolation error. He has the polarized radiative correction code running, and <br>has completed a systematic uncertainty study on the inelastic radiative corrections. He is also working <br>on evaluating physics quantities using models, specifically the hyperfine splitting calculation. He plans <br>to graduate in summer/fall of 2016 and would like to include full radiative corrections on g2p polarized <br>cross sections in his thesis. More details can be seen in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_101315.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*Important to do cross checks of results between students (ex. asymmetries)<br />
*Must be careful to include details of any physics results (whether radiative corrections are included,<br>dilution factor, model input instead of data, etc.)<br />
<br />
==9/30/2015==<br />
<br />
Present: JP, Kalyan, Jixie, Min <br><br />
By Phone: Pengjia, Toby, Ryan, Vince, Jie, Chao, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Toby<br />
**Showed an update on his acceptance/dilution study. He continued with the study of the cuts on the <br>reconstructed &theta; vs &phi; distribution at the target. He scanned several different &theta; vs &phi; cuts to see how <br>the acceptance effects the scattering angle and resulting yields. It turns out the small angle region is <br>influenced by the acceptance a lot but the center region gives a good agreement to the model. He <br>also loosed the center cut to &theta; ~ ± 40 mrad and &phi; ~ ± 10 mrad, the data still agreed with the model. <br>He then recalculated the dilution factor for 2.254 GeV longitudinal setting. More details on his <br>acceptance cuts and method can be found in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/diltalk_093015.pdf here].<br />
<br />
==9/23/2015==<br />
<br />
Present: JP, Kalyan, Min, Melissa <br><br />
By Phone: Pengjia, Toby, Ryan, Vince, Jie, Chao, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Pengjia<br />
**Showed the structure of his code to create a radiated model of the MAID and Bosted <br>models, based on Ryan's radiative correction work. He showed the breakdown of the <br>different components to the radiated model (internal, external and elastic tail). He used<br> the radiated model to calculate an asymmetry and cross section differences, which he <br> compared with data. Finally, he combined asymmetries calculated from data with the <br>Bosted model cross section to calculate a value for g1 and g2, which he compared <br>with values of g1/g2 determined using the MAID model. More details can be seen in <br>his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/09222015/asym_g12.pdf here].<br />
<br />
*Min<br />
**Gave an update on acceptance studies. Last time, she found that by adjusting the<br>apertures in the simulation she could match the data/simulation results for dp (for one <br>momentum setting). She tested this method for other momentum settings and found <br>that it did not work as well. She also showed a comparison of the yield spectrum for<br>helium runs in the 1.7 GeV setting; the shape of the two distributions are quite <br>different, which might suggest that the model deviates significantly form the data. In<br>the simulated results she saw several "bumps" in the yield, which correspond to the<br>location of resonances. She will update these results when the optics corrections are <br>complete. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/09232015.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*We would like to schedule another collaboration meeting in the near future. The <br>meeting is tentatively scheduled for Wednesday October 14th during our usual meeting <br>time (10am-12pm).<br />
*The purpose of the meeting is to:<br />
**Discuss student thesis topics (particularly any updates from the last <br>collaboration meeting)<br />
**Establish a procedure for presentation/release of collaboration plots/results<br />
*Each student should prepare a few slides (~5 minutes) to show analysis progress<br />
<br />
<br />
==9/16/2015==<br />
<br />
Present: Min, JP, Jixie, Melissa <br><br />
By Phone: Vince, Jie, Chao, Pengjia, Alex, Ryan, Toby, Ellie <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Jie<br />
**Gave an update on his simulation study using MUDIFI. Last time he showed that he uses a<br>least square fit to go from endplane to endplane. For the g2p simulation, it's used to go from<br>(x,y,&theta;,&phi;,dp) in the target plane to (x,y,&theta;,&phi;,dp) in the focal plane. SNAKE produces (x,y,&theta;,&phi;,dp)<br>data in both planes and a polynomial function can be used to determine the relationship<br>between the two planes. First the maximum power for each variable is determined, symmetries<br>are included (if applicable), then the priority of each function must be determined. A Gram-<br>Schmidt transformation is used to do the minimization, and the final step is to decide whether<br>to accept the function f<sub>i</sub>. JP/Vince asked how the priority for each function is chosen, since the<br>choice could introduce some ordering dependence. Since we don't have enough data to<br>constrain, JP suggested introducing some physics. He also suggested getting rid of dp in the<br>focal plane (since it is really just dp in the target plane) so that there is one less dimension to<br>fit. More details can be seen in Jie's slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_09_15_simulation/2015_09_15_Simulation_update.pdf here].<br />
<br />
*Ryan<br />
**Gave an update on evaluating physics quantities using models. His goal was to do a<br>comparison of the hyperfine splitting calculation in C. Carlson's 2006/2008 paper using MAID<br>and Hall B models. Previously he showed a comparison using the Hall B model, where he saw<br>good agreement between his calculation and Carlson's result. For this time he also did a<br>comparison using the MAID model. There is a large difference between the two models for the<br>value of the integrand of &Delta;<sub>2</sub>, over the full range of Q<sup>2</sup>. JP suggested comparing the value of g2<br>between the two models, instead of &Delta;<sub>2</sub>. More details can be seen in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_091615.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*Toby<br />
**Last time he showed a comparison between data and cross sections calculated using the<br>Bosted model (seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/acceptance_scatangle.pdf here]). The model was not continuous for one momentum setting. It <br>turns out the BPM was not recording for that setting, so he re-calculated the XS using<br>values for &theta; and &phi; from surrounding runs and found that the result was now consistent with<br>the neighboring momentum settings. He also played around with the acceptance cuts he<br>showed, and found a region using the "extreme cut" where the sawtooth pattern go away<br>and the yields become flat.<br />
<br />
<br />
==9/9/2015==<br />
<br />
Present: Min, JP, Jixie, Melissa <br><br />
By Phone: Vince, Jie, Chao, Ryan, Toby, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Jie<br />
**Gave an overview of his simulation study using SNAKE and MUDIFI. Using SNAKE, the<br>idea is to trace the particle trajectory in a series of free boxes, then an endplane can be<br>defined within the free boxes to determine the trajectory from endplane to endplane. In<br>g2psim this will be used to trace the trajectory between the sieve plane and the focal<br>plane. There are two important issues to consider, the magnetic field in the free boxes,<br>and the transportation method between the two endplanes. A Runge-Kutta method is <br>used for the transportation, and an adaptive method (which changes with field size and<br>gradient) is used to determine the step size. For the magnetic field, a 3D Tosca field<br>map is used for the septum, and an analytic model is used for the spectrometer magnets. <br> He also described the method for choosing the transportation function to determine the <br>25 matrix terms for each kinematic variable (up to 4th order). JP asked how to determine <br>which order is more important, and cautioned to be careful not to over fit the data. He and<br>Jie will discuss this more offline. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_09_09_simulation_update/2015_09_09_Simulation%20update.pdf here].<br />
<br />
*Chao<br />
**Gave an optics status update. The current problem is that changes in the horizontal beam<br>position changes the dp reconstruction. This was fixed by applying a linear correction in<br>BPM-x and BPM-y to &theta;, &phi; and dp. Applying this correction made the data/simulation <br>agree, but it is still necessary to understand the correction. Using dp scan data with beam<br>position scan data still leaves an offset in &theta; and &phi;. He also tried two other methods to do<br>the calibration. Method 1 uses the central hole to determine a constant offset, uses the<br>horizontal beam position scan data to determine all the matrix elements related to y, and<br>uses dp scan runs to fit the additional matrix elements. Method 2 uses beam position<br>scan data to determine the matrix elements that are not related to x<sub>fp</sub>. Neither of these<br>methods works very well, even when the fitting order of the matrix elements are adjusted.<br>He will continue to check more fitting procedures. More details can be found in his slides <br>[http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150909/Chao_WeeklyMeeting_09092015.pdf here].<br />
<br />
*Pengjia<br />
**Gave an update on comparing asymmetries from data/models for the 2.2 GeV, 5T <br>longitudinal setting. He first radiated the Bosted model XS; he showed the break down of<br>the different radiative corrections including the elastic tail (internal and external) and the<br>radiative effects from inelastic scattering. He showed a comparison with Ryan's results<br>which had good agreement, though there is some deviation when he used different proton<br>form factors (provided by Moshe). In order to compare the asymmetry result with data, he<br>needs to do the radiative corrections for the polarized MAID model, which he will continue<br>to work on. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/09092015/asym_20150909.pdf here].<br />
<br />
<br />
==9/2/2015==<br />
<br />
Present: JP, Min, Kalyan, Melissa <br><br />
By Phone: Vince, Alex, Jie, Chao, Ryan, Toby, Ellie, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Gave an update on determining the correction to asymmetries for pion contamination. <br>Previously, she used the 2.2 GeV, 5T longitudinal setting as an example, for this time <br>she used the transverse configuration, as it has the largest pion contamination. She <br>modified her method for differentiating between electrons and pions; previously she <br>identified pions as events that do not trigger the Cherenkov, this time she used a cut <br>below the single photo electron peak to select pions. JP suggested using stricter cuts <br>for selecting pions when determining the pion asymmetry, to make sure it is a clean <br>sample. Although this setting has a large pion contamination, the number of pion<br> events that remain after lead glass cuts are applied is low, so the overall correction <br>is very small. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Pion/PionAsym_08_31.pdf here].<br />
<br />
*Min<br />
**Gave an update on acceptance tuning. She looked at results from the 1.7 GeV setting <br>and found that the height of the peaks is different between data and simulation for <br>different holes in the sieve slit. Looking at the &theta; vs &phi; distribution, she noticed on the<br>positive &theta; side there were fewer holes in simulation than in data, and on the negative <br> &theta; side there were more holes in simulation compared to data. She tried adjusting the<br>aperture cuts by changing the physical location of the Q1, Q2 and septum planes to <br>uncover events that were previously blocked. After the adjustment, the data/simulation <br>results agreed much better. She showed a similar procedure for a dilution run and was<br>able to see better agreement between data/simulation after the aperture adjustments <br>were made. JP/Vince suggested being cautious when adjusting the aperture cuts, as<br> the apertures should be well defined already. They suggested adjusting things that are<br> less well known first, such as the septum field. More details can be seen in her slides<br>[http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/09022015.pdf here].<br />
<br />
*Ryan<br />
**Working on generating physics quantities using models to eventually compare with data.<br>So far, he has incorporated the MAID2007 and Hall B models. He calculated the <br>hyperfine splitting quantities &Delta;1 and &Delta;2 using the Hall B EG1 model and compared them<br> to the results in C. Carlson's 2006 paper. His results agreed very well, he only saw a<br> small deviation for &Delta;2 in the lowest Q<sup>2</sup> range. To check that nothing strange was going <br> on in the low Q<sup>2</sup> range, he calculated &Delta;2 for various small ranges around zero, to ensure<br>that the integration method is well behaved. The Carlson paper also includes calculations <br>using the Simula model, he would like to do a check of this method as well, but is unsure <br>where to find the Simula model. Since he was able to reproduce the hyperfine splitting <br>result, he is confident in his calculation method; it should be straightforward to calculate <br>other spin structure function integrals. More details on his method can be found in his <br>slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_09215.pdf here].<br />
<br />
*Toby<br />
**Showed an update on his acceptance/scattering angle study. He applied cuts of varying<br>strictness on the reconstructed &theta; vs &phi; distribution at the target. He then calculated the <br>real scattering angle before/after scattering for each cut. Using these scattering angles <br> as inputs for the Bosted model he was able to calculate the XS and compare it to data.<br>He showed the comparison between data/Bosted model for each acceptance cut. He <br>hoped that the more extreme acceptance cuts on the data would flatten the yield <br>distribution, but it actually just enhanced the sawtooth pattern. JP questioned why the <br>Bosted prediction for one momentum bin (the green one) was so much lower than the<br> neighboring ones. Toby said the only input that goes into the model is the scattering angle,<br> so it must be considerably different for this momentum setting. He also commented that<br>the model prediction is scaled to match the data, so the scaling enhances the jump in<br>the model. More details on his acceptance cuts and method can be found in his slides<br>[http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/acceptance_scatangle.pdf here].<br />
<br />
<br />
==8/26/2015==<br />
<br />
Present: Jixie, Alex, Min, Kalyan, JP, Chao, Melissa <br><br />
By Phone: Vince, Jie, Ryan, Toby, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Chao<br />
**Gave an update on optics studies. Previously, he showed a comparison between optics data <br>and simulation where he cut on individual sieve holes. For this week, he included a cut on y <br>and dp that he didn't include previously. In the plot of &theta; vs y, JP pointed out that there were <br>additional tails on some sieve holes, Chao says these tails go away when the &phi; cut is <br>included. He showed a 2D plot of &theta; vs &phi;, along with the 1D projection of these variables. JP<br>commented that the data is more smeared out than the simulation, so it is difficult to compare <br>data with simulation results. It's possible that some of the smearing comes from events that <br>punch through the sieve slit and are not being cut out (the simulation currently assumes these <br>events are stopped by the sieve). Looking at the center hole, the data/simulation agree <br>reasonably well, but the agreement gets worse for holes on the edge of the sieve slit. Chao<br>will continue to look into this. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150826/Chao_WeeklyMeeting_08262015.pdf here].<br />
**He also mentioned that ~1 month ago he reported a problem with the [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150708/Chao_WeeklyMeeting_07082015.pdf BPM simulation].<br>He found it was actually a problem with the simulation itself, which has now been updated <br> to correct the problem.<br />
<br />
<br />
'''General Discussion:'''<br />
*Pengjia has submitted his BPM NIM paper.<br />
<br />
<br />
==8/19/2015==<br />
<br />
Present: Chao, Jie, Min, Jixie, Kalyan, Melissa <br><br />
By Phone: Vince, Ryan, Toby, Karl, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Showed a method for determining the correction to asymmetries for pion contamination. The <br>measured asymmetry can be written in terms of the electron and pion asymmetries, multiplied <br>by the fraction of events of that particle. To differentiate between electrons and pions, a cut is<br>made on events that trigger the Cherenkov detector (electrons) and events that do not trigger<br>the Cherenkov (pions). Kalyan commented that this method of selecting pions may be too blind,<br> and suggested making a 2D cut on E/p vs Cherenkov instead. To determine the fraction of<br>electrons/pions, "good event" cuts are applied (loose acceptance cuts, single track events and<br>pion rejector cuts) and the number of electrons/pions that survive the cuts are counted. Although<br>the pion asymmetry is much larger than the electron asymmetry, the number of residual pions<br>is very small, so the overall correction is small. For this example the 2.2 GeV, 5T longitudinal<br>setting was used, but the correction may be larger for the 5T transverse settings, which she <br>will do next. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Pion/PionAsym_08_19.pdf here].<br />
<br />
*Min <br />
**Gave an update on acceptance studies. She used the 1.7 GeV, 2.5T setting (with 3rd septum <br>configuration) to test the acceptance cuts using the yield ratio of data to simulation. She <br>showed a plot of target &theta; vs &phi; for both data and simulation, and applied a graphical cut to get<br>rid of events on the edges. Looking at the resulting 1D plots shows reasonable agreement<br>between &theta; and &phi;. Vince pointed out that there seems to be some additional structure in the<br>dp distribution, and suggested expanding the &delta; cut out to &pm; 4% to see if there is more <br>hidden structure. Min said she has seen this in other settings as well and will look into it. She<br>also tried adjusting the cuts on &theta;, &phi; and &delta; and looked at how the ratio of yields from data/<br>simulation changed; the ratio starts to drop off as the cuts get wider. Next she will work on<br>calculating the yields using W bins. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/08192015.pdf here].<br />
<br />
<br />
==8/12/2015==<br />
<br />
Present: Jie, Chao, Kalyan, Min, Jixie, Melissa <br><br />
By Phone: Pengjia, Ryan, Toby, Karl, Ellie, Alex <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Chao<br />
**Gave an update on optics studies. Previously, Min has shown comparisons of data/simulation<br> where she looked at different columns of sieve holes. Chao continued this study by cutting on <br>individual sieve holes. Looking at the center sieve hole, the &phi; distribution looks reasonable, but <br>the &theta; distribution has some issues. Specifically, the data is wider on the left side (negative &theta;) <br>than the simulation. He showed results for several sieve holes, including one that was in the <br>row as the center hole, but in the farthest column on the left side of the sieve slit. In this case <br>the &theta; distribution had similar width for both data and simulation, but the height of the simulation<br> distribution was larger. This may suggest that something is wrong with the acceptance in the <br>simulation. The problem with &theta; seems to be systematic; for most of the sieve holes there are <br>more events on the left side of the data than in the simulation. Kalyan asked whether the <br>thickness of the sieve slit was taken into account, Chao says it was included in the simulation <br>and optimizer. Jixie suggested comparing the dp distributions for each sieve hole. More details <br>can be seen in Chao's slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150812/Chao_WeeklyMeeting_08122015.pdf here].<br />
<br />
<br />
==7/29/2015==<br />
<br />
Present: Chao, Min, JP, Melissa <br><br />
By Phone: Alex, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Min<br />
**Gave an update on acceptance studies. Previously, Chao showed a correction for the beam<br>position in g2psim. Min checked this correction by looking at optics runs. On the data she <br>applied a cut on dp (to select elastic events) and on the focal plane (to get rid of junk <br> events). On the simulation, only an aperture cut was applied. She compared the data and<br>simulation results for &theta; and &phi; both before and after drifting from the sieve slit to the target.<br>The effect of the target field on &theta; is not very large, though there is a shift down in angle.<br>However, the shape of the &theta; distribution is different between data and simulation. The<br>effect of the target field on &phi; is significant; it's not clear why this is the case. To try to<br>determine the reason for the discrepancies, she applied a cut along each column of sieve<br>slit holes in &phi; and compared the data and simulation results for &theta;,&phi; and dp. Column 2<br>seems to have the best agreement (for dp), columns 1 and 2 have a shift while columns<br>3-6 have a difference in width. Chao suggested also cutting along each row of sieve slit<br>holes to better study the effect of the drift on &phi;. Min will work on identifying the differences<br>between data and simulation, specifically whether the boundaries are different between<br>the two. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07272015/07292015.pdf here].<br />
<br />
<br />
==7/22/2015==<br />
<br />
Present: JP, Min, Jixie, Melissa <br><br />
By Phone: Alex, Ryan, Toby, Ellie, Karl, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Showed various checks for packing fraction runs that have large discrepancies, including <br>beam position, beam energy, spectrometer central momentum setting, septum current, and<br>the location of anneals. For both the 2.2 and 1.1 GeV settings, there are significant shifts in <br>the x and y beam position (2mm or more). She showed the average and standard deviation <br> of epics readings for the LHRS septum current for each run. For several runs, there are small <br>number of epics readings that drift from the average current. It's not clear if this is the <br>current is actually changing or if it is a readout problem. She will look into the yield vs time<br>to try to determine this. JP suggested making a raster cut on the center of the beam to get<br> rid of any potential scraping. Pengjia says there is a way to cut on raster size, but there will<br> be an additional BPM uncertainty. Melissa will discuss this more offline with Pengjia. More<br>details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_07_22.pdf here].<br />
<br />
*Pengjia<br />
**Gave an update on calculating asymmetries/cross sections using the MAID model. This time, <br>he used the Bosted model to get the unpolarized cross sections for the proton. Using unradiated <br>cross section models, he still saw a factor of 6 difference when compared with data. Ryan also <br>calculated asymmetries using unradiated models, and the results were consistent with Pengjia's, <br>so it seems the radiative effects contribute significantly to the factor of 6 difference. More <br>details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07222015/MAID_update_20150722.pdf here].<br />
<br />
<br />
==7/15/2015==<br />
<br />
Present: JP, Min, Chao, Jixie, Melissa <br><br />
By Phone: Ryan, Toby, Ellie, Karl, Vince, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Chao<br />
**Doing a check of simulation/data results for the 2.2 GeV, longitudinal setting in order <br>to check that the optics calibration matrix will work for all momentum settings (not <br>just elastic). He showed a comparison for several different momentum settings.<br> Vince suggested simulating more events, since the statistics start to drop off for <br>lower momentum settings. In general, the data is broader then the result from<br>simulation. In the &theta; distribution, the "tails" seen in the data are not symmetric. JP<br> suggested carefully selecting cuts to remove any background from the data to <br>ensure a good comparison with simulation. More details can be seen in his <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150715/Chao_WeeklyMeeting_07152015.pdf here].<br />
<br />
*Pengjia<br />
**More discussion on Pengjia's [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07082015/MAID_update_20150708.pdf slides] from last week. Pengjia has seen a factor of <br>six difference between his asymmetry calculated from data compared to the <br>asymmetry determined using the MAID model. Ryan did not see this factor of six <br>in his study, but in addition to using radiated XS models, he is using a combination <br>of the Bosted and MAID models (Pengjia is using just the MAID model). Karl <br>commented that the XS from MAID is not very good for our kinematics. Pengjia <br>also showed an estimated NH3 XS. JP commented that it was surprising that the <br>delta peak wasn't visible. Pengjia will look into this for next time.<br />
<br />
<br />
==7/8/2015==<br />
<br />
Present: JP, Min, Chao, Melissa <br><br />
By Phone: Toby, Vince <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Pengjia<br />
**Working on comparing asymmetries determined from MAID to those calculated from <br>data; last time he showed a factor of 6 difference between the two results. This <br>time, he showed two different methods for calculating the differential XS from the <br>virtual photon XS. The first method calculates the differential XS directly from <br>the virtual photon XS, and the second method calculates the differential XS using <br>F<sub>1</sub>, F<sub>2</sub>, g<sub>1</sub> and g<sub>2</sub>. He also showed two different methods for calculating the <br>asymmetry from the virtual photon XS; one method uses A<sub>1</sub> and A<sub>2</sub>, while the other <br>is calculated from the virtual photon XS. There was a discrepancy between the two <br>methods, but he found that there was actually a mistake in one of the equations. <br>While the results from the two methods agree with each other, they are still a factor <br>of 6 larger than the results from data. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07082015/MAID_update_20150708.pdf here].<br />
<br />
*Toby<br />
**Showed an update of his scattering angle study for model reconstruction. He is <br>using BPM and optics data to determine the scattering angle. He showed an example <br>of the calculated scattering angle; JP questioned whether the range was really from <br>0-16 deg. Toby pointed out that there really aren't many events at the boundaries, <br>the distribution is peaked between 4.5-9 deg. He then uses this scattering angle as<br>input for the Bosted model. At low &nu; the simulation results match reasonably well<br>with the data, but the discrepancy starts to become larger as &nu; increases. He took <br>a closer look at the reconstructed scattering angle for each central momentum, and <br>found that a second peak is visible for smaller values of p0. If this second peak was <br>real, the simulation should recreate the data, so this could suggest a problem with <br>the reconstruction. However, Chao pointed out that, for this energy setting, the optics <br>calibration is not complete (currently using the longitudinal optics matrix), so the <br>reconstructed &theta; and &phi; may not be correct yet. For next time, Toby will test this <br>analysis using the 1.7 GeV setting, which has calibrated optics. More details can <br> be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/scatangle_talk.pdf here].<br />
<br />
*Melissa<br />
**Gave a summary of packing fraction analysis. For some settings, the variation in the <br>yields (and P<sub>f</sub>) is due to a fluctuation in the beam position. This will hopefully be<br>resolved by Jie's beam position/acceptance study. For the 2.2 GeV, 2.5T transverse setting<br> there is also an issue of a shift in &nu; between runs. For the 1.1 GeV, 2.5T transverse <br>setting, the yields vary depending on the beam current used for each run. JP suggested <br>a few things to check as the possible cause for these discrepancies including drift in the <br>BCM calibration, anneals of the target material, drift in field (HRS or septum), etc. She <br>has posted a technote draft [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Technotes/PF_technote_draft.pdf here], feedback would be appreciated. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_07_08.pdf here].<br />
<br />
*Min<br />
**Gave an update on her acceptance study. Last time, she showed that the simulation results <br>are more narrow than the data. For this time, she tried cutting on just the center hole, <br>and found that the dp distribution from data better matched the simulation. JP suggested <br>cutting on each of the different holes individually to determine which hole causes the dp <br>distribution to be wider. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07082015/07062015.pdf here].<br />
<br />
*Chao<br />
**Gave an update on optics analysis, currently checking whether simulation results match <br>with data, starting with optics data. First he checked whether the geometry was correct, <br>some deviation was found in the recent optics meeting. The position of the BPMs is hard-<br>coded into the simulation, and the drifting algorithm is used to drift the electrons <br>backward to the BPMs to simulate the readout of BPM A and B. He compared the &theta; <br>distribution before drifting in the target field using a fixed and non-fixed BPM location. <br>The results using a fixed BPM match well with the data. He is currently working on <br>checking this for all momentum settings, and will follow up with Pengjia about the BPM <br>problem. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150708/Chao_WeeklyMeeting_07082015.pdf here].<br />
<br />
<br />
==7/1/2015==<br />
<br />
Present: Chao, Vince, Jie, JP, Min, Melissa <br><br />
By Phone: Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Min<br />
**Gave an update on acceptance studies. She showed a summary table of each energy <br>setting and septum configuration. There hasn't been any problems in the 2.2 GeV, 5T <br>longitudinal and 1.7 GeV, 2.5T transverse settings, but some settings (2.2 GeV, 2.5T <br> transverse, 1.2 GeV, 2.5T transverse and 2.2 GeV, 5T transverse) have a discrepancy <br>in the focal plane between data and simulation. She compared the data divided by the <br>Mott XS to the simulation results without XS, and found that the simulation results <br>of &theta; and &phi; are narrower then the data. JP commented that, while including the Mott<br>XS might change the shape of the distribution, it shouldn't change the boundary. She <br>work on figuring out the cause for this discrepancy before calculating the acceptance. <br>More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07012015/07012015.pdf here].<br />
<br />
*Pengjia<br />
**Comparing asymmetries determined from the MAID model to those calculated from data.<br>Last time he showed a factor of 6 difference between the two results. He determined the <br>scattering angle and Q<sup>2</sup> by fitting the data and compared them to the quantities calculated <br>from MAID. He also showed the results of calculating the quantities g<sub>1</sub>, g<sub>2</sub>, F<sub>1</sub>, F<sub>2</sub>, A<sub>L</sub>, A<sub>T</sub>,<br> dXS<sub>L</sub>, dXS<sub>T</sub>, XS<sub>tot</sub> andXS<sub>mott</sub> using MAID. He hasn't included radiative corrections in his <br>calculations, but this probably won't account for the factor of 6. More details can be seen <br>in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07012015/MAID_20150701.pdf here].<br />
<br />
<br />
----<br />
<br />
==Jan-June 2015==<br />
[[Minutes_Jan2015_to_June2015]]<br />
----<br />
<br />
==July-Dec 2014==<br />
[[Minutes_July2014_to_Dec2014]]<br />
----<br />
<br />
==Jan-June 2014==<br />
[[Minutes_Jan2014_to_June2014]]<br />
----<br />
<br />
==June-Dec 2013==<br />
[[Minutes_June2013_to_Dec2013]]<br />
----<br />
<br />
==Jan-May 2013==<br />
[[Minutes_Jan2013_to_May2013]]<br />
----<br />
<br />
==April-Dec 2012==<br />
[[Minutes_Apr2012_to_Dec2012]]<br />
----<br />
<br />
==Jan-March 2012==<br />
[[Minutes_Jan2012_to_Mar2012]]<br />
----<br />
==July-Dec 2011==<br />
[[Minutes_July2011_to_Dec_2011]]<br />
----<br />
==Jan-June 2011==<br />
[[Minutes_Jan2011_to_June_2011]]<br />
----</div>Melissachttps://hallaweb.jlab.org/wiki/index.php?title=G2p_Analysis_Minutes&diff=26094G2p Analysis Minutes2015-10-14T19:54:44Z<p>Melissac: /* 9/30/2015 */</p>
<hr />
<div>Minutes of the weekly analysis meetings<br />
----<br />
[https://hallaweb.jlab.org/wiki/index.php/G2p_Weekly_Analysis Agenda]<br />
<br />
==10/14/2015==<br />
<br />
Present: JP, Min, Jixie, Kalyan, Melissa <br><br />
By Phone: Alexandre, Vince, Jie, Todd, Haiyan, Pengjia, Karl, Toby, Ryan, Xiaochao, Nilanga, Chao <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Karl<br />
**<br />
<br />
<br />
<br />
==9/30/2015==<br />
<br />
Present: JP, Kalyan, Jixie, Min <br><br />
By Phone: Pengjia, Toby, Ryan, Vince, Jie, Chao, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Toby<br />
**Showed an update on his acceptance/dilution study. He continued with the study of the cuts on the <br>reconstructed &theta; vs &phi; distribution at the target. He scanned several different &theta; vs &phi; cuts to see how <br>the acceptance effects the scattering angle and resulting yields. It turns out the small angle region is <br>influenced by the acceptance a lot but the center region gives a good agreement to the model. He <br>also loosed the center cut to &theta; ~ ± 40 mrad and &phi; ~ ± 10 mrad, the data still agreed with the model. <br>He then recalculated the dilution factor for 2.254 GeV longitudinal setting. More details on his <br>acceptance cuts and method can be found in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/diltalk_093015.pdf here].<br />
<br />
==9/23/2015==<br />
<br />
Present: JP, Kalyan, Min, Melissa <br><br />
By Phone: Pengjia, Toby, Ryan, Vince, Jie, Chao, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Pengjia<br />
**Showed the structure of his code to create a radiated model of the MAID and Bosted <br>models, based on Ryan's radiative correction work. He showed the breakdown of the <br>different components to the radiated model (internal, external and elastic tail). He used<br> the radiated model to calculate an asymmetry and cross section differences, which he <br> compared with data. Finally, he combined asymmetries calculated from data with the <br>Bosted model cross section to calculate a value for g1 and g2, which he compared <br>with values of g1/g2 determined using the MAID model. More details can be seen in <br>his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/09222015/asym_g12.pdf here].<br />
<br />
*Min<br />
**Gave an update on acceptance studies. Last time, she found that by adjusting the<br>apertures in the simulation she could match the data/simulation results for dp (for one <br>momentum setting). She tested this method for other momentum settings and found <br>that it did not work as well. She also showed a comparison of the yield spectrum for<br>helium runs in the 1.7 GeV setting; the shape of the two distributions are quite <br>different, which might suggest that the model deviates significantly form the data. In<br>the simulated results she saw several "bumps" in the yield, which correspond to the<br>location of resonances. She will update these results when the optics corrections are <br>complete. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/09232015.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*We would like to schedule another collaboration meeting in the near future. The <br>meeting is tentatively scheduled for Wednesday October 14th during our usual meeting <br>time (10am-12pm).<br />
*The purpose of the meeting is to:<br />
**Discuss student thesis topics (particularly any updates from the last <br>collaboration meeting)<br />
**Establish a procedure for presentation/release of collaboration plots/results<br />
*Each student should prepare a few slides (~5 minutes) to show analysis progress<br />
<br />
<br />
==9/16/2015==<br />
<br />
Present: Min, JP, Jixie, Melissa <br><br />
By Phone: Vince, Jie, Chao, Pengjia, Alex, Ryan, Toby, Ellie <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Jie<br />
**Gave an update on his simulation study using MUDIFI. Last time he showed that he uses a<br>least square fit to go from endplane to endplane. For the g2p simulation, it's used to go from<br>(x,y,&theta;,&phi;,dp) in the target plane to (x,y,&theta;,&phi;,dp) in the focal plane. SNAKE produces (x,y,&theta;,&phi;,dp)<br>data in both planes and a polynomial function can be used to determine the relationship<br>between the two planes. First the maximum power for each variable is determined, symmetries<br>are included (if applicable), then the priority of each function must be determined. A Gram-<br>Schmidt transformation is used to do the minimization, and the final step is to decide whether<br>to accept the function f<sub>i</sub>. JP/Vince asked how the priority for each function is chosen, since the<br>choice could introduce some ordering dependence. Since we don't have enough data to<br>constrain, JP suggested introducing some physics. He also suggested getting rid of dp in the<br>focal plane (since it is really just dp in the target plane) so that there is one less dimension to<br>fit. More details can be seen in Jie's slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_09_15_simulation/2015_09_15_Simulation_update.pdf here].<br />
<br />
*Ryan<br />
**Gave an update on evaluating physics quantities using models. His goal was to do a<br>comparison of the hyperfine splitting calculation in C. Carlson's 2006/2008 paper using MAID<br>and Hall B models. Previously he showed a comparison using the Hall B model, where he saw<br>good agreement between his calculation and Carlson's result. For this time he also did a<br>comparison using the MAID model. There is a large difference between the two models for the<br>value of the integrand of &Delta;<sub>2</sub>, over the full range of Q<sup>2</sup>. JP suggested comparing the value of g2<br>between the two models, instead of &Delta;<sub>2</sub>. More details can be seen in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_091615.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*Toby<br />
**Last time he showed a comparison between data and cross sections calculated using the<br>Bosted model (seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/acceptance_scatangle.pdf here]). The model was not continuous for one momentum setting. It <br>turns out the BPM was not recording for that setting, so he re-calculated the XS using<br>values for &theta; and &phi; from surrounding runs and found that the result was now consistent with<br>the neighboring momentum settings. He also played around with the acceptance cuts he<br>showed, and found a region using the "extreme cut" where the sawtooth pattern go away<br>and the yields become flat.<br />
<br />
<br />
==9/9/2015==<br />
<br />
Present: Min, JP, Jixie, Melissa <br><br />
By Phone: Vince, Jie, Chao, Ryan, Toby, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Jie<br />
**Gave an overview of his simulation study using SNAKE and MUDIFI. Using SNAKE, the<br>idea is to trace the particle trajectory in a series of free boxes, then an endplane can be<br>defined within the free boxes to determine the trajectory from endplane to endplane. In<br>g2psim this will be used to trace the trajectory between the sieve plane and the focal<br>plane. There are two important issues to consider, the magnetic field in the free boxes,<br>and the transportation method between the two endplanes. A Runge-Kutta method is <br>used for the transportation, and an adaptive method (which changes with field size and<br>gradient) is used to determine the step size. For the magnetic field, a 3D Tosca field<br>map is used for the septum, and an analytic model is used for the spectrometer magnets. <br> He also described the method for choosing the transportation function to determine the <br>25 matrix terms for each kinematic variable (up to 4th order). JP asked how to determine <br>which order is more important, and cautioned to be careful not to over fit the data. He and<br>Jie will discuss this more offline. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_09_09_simulation_update/2015_09_09_Simulation%20update.pdf here].<br />
<br />
*Chao<br />
**Gave an optics status update. The current problem is that changes in the horizontal beam<br>position changes the dp reconstruction. This was fixed by applying a linear correction in<br>BPM-x and BPM-y to &theta;, &phi; and dp. Applying this correction made the data/simulation <br>agree, but it is still necessary to understand the correction. Using dp scan data with beam<br>position scan data still leaves an offset in &theta; and &phi;. He also tried two other methods to do<br>the calibration. Method 1 uses the central hole to determine a constant offset, uses the<br>horizontal beam position scan data to determine all the matrix elements related to y, and<br>uses dp scan runs to fit the additional matrix elements. Method 2 uses beam position<br>scan data to determine the matrix elements that are not related to x<sub>fp</sub>. Neither of these<br>methods works very well, even when the fitting order of the matrix elements are adjusted.<br>He will continue to check more fitting procedures. More details can be found in his slides <br>[http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150909/Chao_WeeklyMeeting_09092015.pdf here].<br />
<br />
*Pengjia<br />
**Gave an update on comparing asymmetries from data/models for the 2.2 GeV, 5T <br>longitudinal setting. He first radiated the Bosted model XS; he showed the break down of<br>the different radiative corrections including the elastic tail (internal and external) and the<br>radiative effects from inelastic scattering. He showed a comparison with Ryan's results<br>which had good agreement, though there is some deviation when he used different proton<br>form factors (provided by Moshe). In order to compare the asymmetry result with data, he<br>needs to do the radiative corrections for the polarized MAID model, which he will continue<br>to work on. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/09092015/asym_20150909.pdf here].<br />
<br />
<br />
==9/2/2015==<br />
<br />
Present: JP, Min, Kalyan, Melissa <br><br />
By Phone: Vince, Alex, Jie, Chao, Ryan, Toby, Ellie, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Gave an update on determining the correction to asymmetries for pion contamination. <br>Previously, she used the 2.2 GeV, 5T longitudinal setting as an example, for this time <br>she used the transverse configuration, as it has the largest pion contamination. She <br>modified her method for differentiating between electrons and pions; previously she <br>identified pions as events that do not trigger the Cherenkov, this time she used a cut <br>below the single photo electron peak to select pions. JP suggested using stricter cuts <br>for selecting pions when determining the pion asymmetry, to make sure it is a clean <br>sample. Although this setting has a large pion contamination, the number of pion<br> events that remain after lead glass cuts are applied is low, so the overall correction <br>is very small. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Pion/PionAsym_08_31.pdf here].<br />
<br />
*Min<br />
**Gave an update on acceptance tuning. She looked at results from the 1.7 GeV setting <br>and found that the height of the peaks is different between data and simulation for <br>different holes in the sieve slit. Looking at the &theta; vs &phi; distribution, she noticed on the<br>positive &theta; side there were fewer holes in simulation than in data, and on the negative <br> &theta; side there were more holes in simulation compared to data. She tried adjusting the<br>aperture cuts by changing the physical location of the Q1, Q2 and septum planes to <br>uncover events that were previously blocked. After the adjustment, the data/simulation <br>results agreed much better. She showed a similar procedure for a dilution run and was<br>able to see better agreement between data/simulation after the aperture adjustments <br>were made. JP/Vince suggested being cautious when adjusting the aperture cuts, as<br> the apertures should be well defined already. They suggested adjusting things that are<br> less well known first, such as the septum field. More details can be seen in her slides<br>[http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/09022015.pdf here].<br />
<br />
*Ryan<br />
**Working on generating physics quantities using models to eventually compare with data.<br>So far, he has incorporated the MAID2007 and Hall B models. He calculated the <br>hyperfine splitting quantities &Delta;1 and &Delta;2 using the Hall B EG1 model and compared them<br> to the results in C. Carlson's 2006 paper. His results agreed very well, he only saw a<br> small deviation for &Delta;2 in the lowest Q<sup>2</sup> range. To check that nothing strange was going <br> on in the low Q<sup>2</sup> range, he calculated &Delta;2 for various small ranges around zero, to ensure<br>that the integration method is well behaved. The Carlson paper also includes calculations <br>using the Simula model, he would like to do a check of this method as well, but is unsure <br>where to find the Simula model. Since he was able to reproduce the hyperfine splitting <br>result, he is confident in his calculation method; it should be straightforward to calculate <br>other spin structure function integrals. More details on his method can be found in his <br>slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_09215.pdf here].<br />
<br />
*Toby<br />
**Showed an update on his acceptance/scattering angle study. He applied cuts of varying<br>strictness on the reconstructed &theta; vs &phi; distribution at the target. He then calculated the <br>real scattering angle before/after scattering for each cut. Using these scattering angles <br> as inputs for the Bosted model he was able to calculate the XS and compare it to data.<br>He showed the comparison between data/Bosted model for each acceptance cut. He <br>hoped that the more extreme acceptance cuts on the data would flatten the yield <br>distribution, but it actually just enhanced the sawtooth pattern. JP questioned why the <br>Bosted prediction for one momentum bin (the green one) was so much lower than the<br> neighboring ones. Toby said the only input that goes into the model is the scattering angle,<br> so it must be considerably different for this momentum setting. He also commented that<br>the model prediction is scaled to match the data, so the scaling enhances the jump in<br>the model. More details on his acceptance cuts and method can be found in his slides<br>[http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/acceptance_scatangle.pdf here].<br />
<br />
<br />
==8/26/2015==<br />
<br />
Present: Jixie, Alex, Min, Kalyan, JP, Chao, Melissa <br><br />
By Phone: Vince, Jie, Ryan, Toby, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Chao<br />
**Gave an update on optics studies. Previously, he showed a comparison between optics data <br>and simulation where he cut on individual sieve holes. For this week, he included a cut on y <br>and dp that he didn't include previously. In the plot of &theta; vs y, JP pointed out that there were <br>additional tails on some sieve holes, Chao says these tails go away when the &phi; cut is <br>included. He showed a 2D plot of &theta; vs &phi;, along with the 1D projection of these variables. JP<br>commented that the data is more smeared out than the simulation, so it is difficult to compare <br>data with simulation results. It's possible that some of the smearing comes from events that <br>punch through the sieve slit and are not being cut out (the simulation currently assumes these <br>events are stopped by the sieve). Looking at the center hole, the data/simulation agree <br>reasonably well, but the agreement gets worse for holes on the edge of the sieve slit. Chao<br>will continue to look into this. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150826/Chao_WeeklyMeeting_08262015.pdf here].<br />
**He also mentioned that ~1 month ago he reported a problem with the [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150708/Chao_WeeklyMeeting_07082015.pdf BPM simulation].<br>He found it was actually a problem with the simulation itself, which has now been updated <br> to correct the problem.<br />
<br />
<br />
'''General Discussion:'''<br />
*Pengjia has submitted his BPM NIM paper.<br />
<br />
<br />
==8/19/2015==<br />
<br />
Present: Chao, Jie, Min, Jixie, Kalyan, Melissa <br><br />
By Phone: Vince, Ryan, Toby, Karl, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Showed a method for determining the correction to asymmetries for pion contamination. The <br>measured asymmetry can be written in terms of the electron and pion asymmetries, multiplied <br>by the fraction of events of that particle. To differentiate between electrons and pions, a cut is<br>made on events that trigger the Cherenkov detector (electrons) and events that do not trigger<br>the Cherenkov (pions). Kalyan commented that this method of selecting pions may be too blind,<br> and suggested making a 2D cut on E/p vs Cherenkov instead. To determine the fraction of<br>electrons/pions, "good event" cuts are applied (loose acceptance cuts, single track events and<br>pion rejector cuts) and the number of electrons/pions that survive the cuts are counted. Although<br>the pion asymmetry is much larger than the electron asymmetry, the number of residual pions<br>is very small, so the overall correction is small. For this example the 2.2 GeV, 5T longitudinal<br>setting was used, but the correction may be larger for the 5T transverse settings, which she <br>will do next. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Pion/PionAsym_08_19.pdf here].<br />
<br />
*Min <br />
**Gave an update on acceptance studies. She used the 1.7 GeV, 2.5T setting (with 3rd septum <br>configuration) to test the acceptance cuts using the yield ratio of data to simulation. She <br>showed a plot of target &theta; vs &phi; for both data and simulation, and applied a graphical cut to get<br>rid of events on the edges. Looking at the resulting 1D plots shows reasonable agreement<br>between &theta; and &phi;. Vince pointed out that there seems to be some additional structure in the<br>dp distribution, and suggested expanding the &delta; cut out to &pm; 4% to see if there is more <br>hidden structure. Min said she has seen this in other settings as well and will look into it. She<br>also tried adjusting the cuts on &theta;, &phi; and &delta; and looked at how the ratio of yields from data/<br>simulation changed; the ratio starts to drop off as the cuts get wider. Next she will work on<br>calculating the yields using W bins. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/08192015.pdf here].<br />
<br />
<br />
==8/12/2015==<br />
<br />
Present: Jie, Chao, Kalyan, Min, Jixie, Melissa <br><br />
By Phone: Pengjia, Ryan, Toby, Karl, Ellie, Alex <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Chao<br />
**Gave an update on optics studies. Previously, Min has shown comparisons of data/simulation<br> where she looked at different columns of sieve holes. Chao continued this study by cutting on <br>individual sieve holes. Looking at the center sieve hole, the &phi; distribution looks reasonable, but <br>the &theta; distribution has some issues. Specifically, the data is wider on the left side (negative &theta;) <br>than the simulation. He showed results for several sieve holes, including one that was in the <br>row as the center hole, but in the farthest column on the left side of the sieve slit. In this case <br>the &theta; distribution had similar width for both data and simulation, but the height of the simulation<br> distribution was larger. This may suggest that something is wrong with the acceptance in the <br>simulation. The problem with &theta; seems to be systematic; for most of the sieve holes there are <br>more events on the left side of the data than in the simulation. Kalyan asked whether the <br>thickness of the sieve slit was taken into account, Chao says it was included in the simulation <br>and optimizer. Jixie suggested comparing the dp distributions for each sieve hole. More details <br>can be seen in Chao's slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150812/Chao_WeeklyMeeting_08122015.pdf here].<br />
<br />
<br />
==7/29/2015==<br />
<br />
Present: Chao, Min, JP, Melissa <br><br />
By Phone: Alex, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Min<br />
**Gave an update on acceptance studies. Previously, Chao showed a correction for the beam<br>position in g2psim. Min checked this correction by looking at optics runs. On the data she <br>applied a cut on dp (to select elastic events) and on the focal plane (to get rid of junk <br> events). On the simulation, only an aperture cut was applied. She compared the data and<br>simulation results for &theta; and &phi; both before and after drifting from the sieve slit to the target.<br>The effect of the target field on &theta; is not very large, though there is a shift down in angle.<br>However, the shape of the &theta; distribution is different between data and simulation. The<br>effect of the target field on &phi; is significant; it's not clear why this is the case. To try to<br>determine the reason for the discrepancies, she applied a cut along each column of sieve<br>slit holes in &phi; and compared the data and simulation results for &theta;,&phi; and dp. Column 2<br>seems to have the best agreement (for dp), columns 1 and 2 have a shift while columns<br>3-6 have a difference in width. Chao suggested also cutting along each row of sieve slit<br>holes to better study the effect of the drift on &phi;. Min will work on identifying the differences<br>between data and simulation, specifically whether the boundaries are different between<br>the two. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07272015/07292015.pdf here].<br />
<br />
<br />
==7/22/2015==<br />
<br />
Present: JP, Min, Jixie, Melissa <br><br />
By Phone: Alex, Ryan, Toby, Ellie, Karl, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Showed various checks for packing fraction runs that have large discrepancies, including <br>beam position, beam energy, spectrometer central momentum setting, septum current, and<br>the location of anneals. For both the 2.2 and 1.1 GeV settings, there are significant shifts in <br>the x and y beam position (2mm or more). She showed the average and standard deviation <br> of epics readings for the LHRS septum current for each run. For several runs, there are small <br>number of epics readings that drift from the average current. It's not clear if this is the <br>current is actually changing or if it is a readout problem. She will look into the yield vs time<br>to try to determine this. JP suggested making a raster cut on the center of the beam to get<br> rid of any potential scraping. Pengjia says there is a way to cut on raster size, but there will<br> be an additional BPM uncertainty. Melissa will discuss this more offline with Pengjia. More<br>details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_07_22.pdf here].<br />
<br />
*Pengjia<br />
**Gave an update on calculating asymmetries/cross sections using the MAID model. This time, <br>he used the Bosted model to get the unpolarized cross sections for the proton. Using unradiated <br>cross section models, he still saw a factor of 6 difference when compared with data. Ryan also <br>calculated asymmetries using unradiated models, and the results were consistent with Pengjia's, <br>so it seems the radiative effects contribute significantly to the factor of 6 difference. More <br>details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07222015/MAID_update_20150722.pdf here].<br />
<br />
<br />
==7/15/2015==<br />
<br />
Present: JP, Min, Chao, Jixie, Melissa <br><br />
By Phone: Ryan, Toby, Ellie, Karl, Vince, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Chao<br />
**Doing a check of simulation/data results for the 2.2 GeV, longitudinal setting in order <br>to check that the optics calibration matrix will work for all momentum settings (not <br>just elastic). He showed a comparison for several different momentum settings.<br> Vince suggested simulating more events, since the statistics start to drop off for <br>lower momentum settings. In general, the data is broader then the result from<br>simulation. In the &theta; distribution, the "tails" seen in the data are not symmetric. JP<br> suggested carefully selecting cuts to remove any background from the data to <br>ensure a good comparison with simulation. More details can be seen in his <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150715/Chao_WeeklyMeeting_07152015.pdf here].<br />
<br />
*Pengjia<br />
**More discussion on Pengjia's [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07082015/MAID_update_20150708.pdf slides] from last week. Pengjia has seen a factor of <br>six difference between his asymmetry calculated from data compared to the <br>asymmetry determined using the MAID model. Ryan did not see this factor of six <br>in his study, but in addition to using radiated XS models, he is using a combination <br>of the Bosted and MAID models (Pengjia is using just the MAID model). Karl <br>commented that the XS from MAID is not very good for our kinematics. Pengjia <br>also showed an estimated NH3 XS. JP commented that it was surprising that the <br>delta peak wasn't visible. Pengjia will look into this for next time.<br />
<br />
<br />
==7/8/2015==<br />
<br />
Present: JP, Min, Chao, Melissa <br><br />
By Phone: Toby, Vince <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Pengjia<br />
**Working on comparing asymmetries determined from MAID to those calculated from <br>data; last time he showed a factor of 6 difference between the two results. This <br>time, he showed two different methods for calculating the differential XS from the <br>virtual photon XS. The first method calculates the differential XS directly from <br>the virtual photon XS, and the second method calculates the differential XS using <br>F<sub>1</sub>, F<sub>2</sub>, g<sub>1</sub> and g<sub>2</sub>. He also showed two different methods for calculating the <br>asymmetry from the virtual photon XS; one method uses A<sub>1</sub> and A<sub>2</sub>, while the other <br>is calculated from the virtual photon XS. There was a discrepancy between the two <br>methods, but he found that there was actually a mistake in one of the equations. <br>While the results from the two methods agree with each other, they are still a factor <br>of 6 larger than the results from data. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07082015/MAID_update_20150708.pdf here].<br />
<br />
*Toby<br />
**Showed an update of his scattering angle study for model reconstruction. He is <br>using BPM and optics data to determine the scattering angle. He showed an example <br>of the calculated scattering angle; JP questioned whether the range was really from <br>0-16 deg. Toby pointed out that there really aren't many events at the boundaries, <br>the distribution is peaked between 4.5-9 deg. He then uses this scattering angle as<br>input for the Bosted model. At low &nu; the simulation results match reasonably well<br>with the data, but the discrepancy starts to become larger as &nu; increases. He took <br>a closer look at the reconstructed scattering angle for each central momentum, and <br>found that a second peak is visible for smaller values of p0. If this second peak was <br>real, the simulation should recreate the data, so this could suggest a problem with <br>the reconstruction. However, Chao pointed out that, for this energy setting, the optics <br>calibration is not complete (currently using the longitudinal optics matrix), so the <br>reconstructed &theta; and &phi; may not be correct yet. For next time, Toby will test this <br>analysis using the 1.7 GeV setting, which has calibrated optics. More details can <br> be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/scatangle_talk.pdf here].<br />
<br />
*Melissa<br />
**Gave a summary of packing fraction analysis. For some settings, the variation in the <br>yields (and P<sub>f</sub>) is due to a fluctuation in the beam position. This will hopefully be<br>resolved by Jie's beam position/acceptance study. For the 2.2 GeV, 2.5T transverse setting<br> there is also an issue of a shift in &nu; between runs. For the 1.1 GeV, 2.5T transverse <br>setting, the yields vary depending on the beam current used for each run. JP suggested <br>a few things to check as the possible cause for these discrepancies including drift in the <br>BCM calibration, anneals of the target material, drift in field (HRS or septum), etc. She <br>has posted a technote draft [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Technotes/PF_technote_draft.pdf here], feedback would be appreciated. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_07_08.pdf here].<br />
<br />
*Min<br />
**Gave an update on her acceptance study. Last time, she showed that the simulation results <br>are more narrow than the data. For this time, she tried cutting on just the center hole, <br>and found that the dp distribution from data better matched the simulation. JP suggested <br>cutting on each of the different holes individually to determine which hole causes the dp <br>distribution to be wider. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07082015/07062015.pdf here].<br />
<br />
*Chao<br />
**Gave an update on optics analysis, currently checking whether simulation results match <br>with data, starting with optics data. First he checked whether the geometry was correct, <br>some deviation was found in the recent optics meeting. The position of the BPMs is hard-<br>coded into the simulation, and the drifting algorithm is used to drift the electrons <br>backward to the BPMs to simulate the readout of BPM A and B. He compared the &theta; <br>distribution before drifting in the target field using a fixed and non-fixed BPM location. <br>The results using a fixed BPM match well with the data. He is currently working on <br>checking this for all momentum settings, and will follow up with Pengjia about the BPM <br>problem. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150708/Chao_WeeklyMeeting_07082015.pdf here].<br />
<br />
<br />
==7/1/2015==<br />
<br />
Present: Chao, Vince, Jie, JP, Min, Melissa <br><br />
By Phone: Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Min<br />
**Gave an update on acceptance studies. She showed a summary table of each energy <br>setting and septum configuration. There hasn't been any problems in the 2.2 GeV, 5T <br>longitudinal and 1.7 GeV, 2.5T transverse settings, but some settings (2.2 GeV, 2.5T <br> transverse, 1.2 GeV, 2.5T transverse and 2.2 GeV, 5T transverse) have a discrepancy <br>in the focal plane between data and simulation. She compared the data divided by the <br>Mott XS to the simulation results without XS, and found that the simulation results <br>of &theta; and &phi; are narrower then the data. JP commented that, while including the Mott<br>XS might change the shape of the distribution, it shouldn't change the boundary. She <br>work on figuring out the cause for this discrepancy before calculating the acceptance. <br>More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07012015/07012015.pdf here].<br />
<br />
*Pengjia<br />
**Comparing asymmetries determined from the MAID model to those calculated from data.<br>Last time he showed a factor of 6 difference between the two results. He determined the <br>scattering angle and Q<sup>2</sup> by fitting the data and compared them to the quantities calculated <br>from MAID. He also showed the results of calculating the quantities g<sub>1</sub>, g<sub>2</sub>, F<sub>1</sub>, F<sub>2</sub>, A<sub>L</sub>, A<sub>T</sub>,<br> dXS<sub>L</sub>, dXS<sub>T</sub>, XS<sub>tot</sub> andXS<sub>mott</sub> using MAID. He hasn't included radiative corrections in his <br>calculations, but this probably won't account for the factor of 6. More details can be seen <br>in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07012015/MAID_20150701.pdf here].<br />
<br />
<br />
----<br />
<br />
==Jan-June 2015==<br />
[[Minutes_Jan2015_to_June2015]]<br />
----<br />
<br />
==July-Dec 2014==<br />
[[Minutes_July2014_to_Dec2014]]<br />
----<br />
<br />
==Jan-June 2014==<br />
[[Minutes_Jan2014_to_June2014]]<br />
----<br />
<br />
==June-Dec 2013==<br />
[[Minutes_June2013_to_Dec2013]]<br />
----<br />
<br />
==Jan-May 2013==<br />
[[Minutes_Jan2013_to_May2013]]<br />
----<br />
<br />
==April-Dec 2012==<br />
[[Minutes_Apr2012_to_Dec2012]]<br />
----<br />
<br />
==Jan-March 2012==<br />
[[Minutes_Jan2012_to_Mar2012]]<br />
----<br />
==July-Dec 2011==<br />
[[Minutes_July2011_to_Dec_2011]]<br />
----<br />
==Jan-June 2011==<br />
[[Minutes_Jan2011_to_June_2011]]<br />
----</div>Melissachttps://hallaweb.jlab.org/wiki/index.php?title=G2p_Weekly_Analysis&diff=26073G2p Weekly Analysis2015-10-14T12:54:00Z<p>Melissac: /* AGENDAS */</p>
<hr />
<div>Analysis meetings are held every Wednesday at 9:00 in F228. ([https://hallaweb.jlab.org/wiki/index.php/G2p_Analysis_Minutes Minutes])<br />
<br />
The conference phone number is 866-740-1260 (US) or 303-248-0285 (International). Access Code: 1466792<br />
<br />
Please edit the agenda to link to your talk prior to the start of the meeting. For help doing this, [https://hallaweb.jlab.org/wiki/index.php/Getting_Started_with_the_g2pWiki click here] <br />
<br />
Group members can post files at /u/group/halla/www/hallaweb/html/experiment/g2p/collaborators, <br><br />
which will then be accessible on the web from http://hallaweb.jlab.org/experiment/g2p/collaborators/<br />
<br />
=AGENDAS=<br />
<br />
'''Wednesday, October 14 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/slifer/2015/slifer_g2pcollab_101415.pdf Overview] <br />
| Karl<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/graduate_2015.pdf graduate] <br />
| Pengjia<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/talks/MCummings_CollabMeeting_20151013.pdf update] <br />
| Melissa<br />
|}<br />
<br />
<br />
'''Wednesday, September 30 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/diltalk_093015.pdf dilution update] <br />
| Toby<br />
|}<br />
<br />
<br />
'''Wednesday, September 23 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/09222015/asym_g12.pdf asymmetry] <br />
| Pengjia<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/09232015.pdf Acceptance Spectrum] <br />
| Min<br />
|}<br />
<br />
<br />
'''Wednesday, September 16 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_09_15_simulation/2015_09_15_Simulation_update.pdf simulation update] <br />
| jie<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_091615.pdf Model Calc. of Physics Quantities] <br />
| Ryan<br />
|}<br />
<br />
<br />
'''Wednesday, September 9 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_09_09_simulation_update/2015_09_09_Simulation%20update.pdf simulation update] <br />
| jie<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150909/Chao_WeeklyMeeting_09092015.pdf Optics Update] <br />
| Chao<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/09092015/asym_20150909.pdf asymmetry] <br />
| Pengjia<br />
|}<br />
<br />
<br />
'''Wednesday, September 2 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Pion/PionAsym_08_31.pdf Pion Asymmetries] <br />
| Melissa<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_09215.pdf Model Calc. of Physics Quantities] <br />
| Ryan<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/acceptance_scatangle.pdf Scattering Angle study contd.] <br />
| Toby<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/09022015.pdf Acceptance Tuning] <br />
| Min<br />
|}<br />
<br />
<br />
'''Wednesday, August 26 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150826/Chao_WeeklyMeeting_08262015.pdf Optics Update] <br />
| Chao<br />
|}<br />
<br />
<br />
'''Wednesday, August 19 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Pion/PionAsym_08_19.pdf Pion Asymmetries] <br />
| Melissa<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/08192015.pdf Acceptance Update] <br />
| Min<br />
|}<br />
<br />
<br />
'''Wednesday, August 12 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150812/Chao_WeeklyMeeting_08122015.pdf Optics Update] <br />
| Chao<br />
|}<br />
<br />
<br />
'''Wednesday, July 29 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07272015/07292015.pdf Acceptance - Optics run] <br />
| Min<br />
|}<br />
<br />
<br />
'''Wednesday, July 22 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_07_22.pdf Epics Checks for Pf Analysis] <br />
| Melissa<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07222015/MAID_update_20150722.pdf MAID update] <br />
| Pengjia<br />
|}<br />
<br />
<br />
'''Wednesday, July 15 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150715/Chao_WeeklyMeeting_07152015.pdf Optics Update] <br />
| Chao<br />
|}<br />
<br />
<br />
'''Wednesday, July 8 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07082015/MAID_update_20150708.pdf MAID update] <br />
| Pengjia<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/scatangle_talk.pdf model reconstruction - scattering angle study] <br />
| Toby<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_07_08.pdf Summary of Pf Analysis ] <br />
| Melissa<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07082015/07062015.pdf Dp Comparison ] <br />
| Min<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150708/Chao_WeeklyMeeting_07082015.pdf Optics Update] <br />
| Chao<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_07_05_plots/2015_07_06_Simulation_update.pdf Simulation Update] <br />
| Jie<br />
|}<br />
<br />
<br />
'''Wednesday, July 1 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07012015/07012015.pdf Acceptance Update] <br />
| Min<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07012015/MAID_20150701.pdf MAID asymmetry] <br />
| Pengjia<br />
|}<br />
<br />
<br />
'''Wednesday, June 24 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Technotes/PF_technote_draft.pdf PF Technote Draft] <br />
| Melissa<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/asymplots.pdf Asymmetry plots] <br />
| Toby<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_06_24_simulation/2015_06_25_Simulation_update.pdf simulation update] <br />
| Jie<br />
<br />
|}<br />
<br />
<br />
'''Wednesday, June 17 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_061715.pdf Pol Rad Corrections] <br />
| Ryan<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/anglecorrection.pdf Angle Correction to simulation] <br />
| Toby<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/06172015/06172015.pdf Acceptance Study - Dilution] <br />
| Min<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/Chao_WeeklyMeeting_06172015.pdf Optics Update] <br />
| Chao<br />
|}<br />
<br />
<br />
'''Wednesday, June 10 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_06_09_simulation/2015_06_10_Simulation_update.pdf Simulation update] <br />
| Jie<br />
|}<br />
<br />
<br />
'''Wednesday, May 27 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/05272015/maid_asym_20150527.pdf Asymmetries from MAID] <br />
| Pengjia<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/05272015/05272015.pdf Acceptance Update 3rd septum] <br />
| Min<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/05272015/Chao_WeeklyMeeting_05272015.pdf Optics Update] <br />
| Chao<br />
|}<br />
<br />
<br />
'''Wednesday, May 20 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/05202015/maid_asym.pdf Asymmetries from MAID] <br />
| Pengjia<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_05_20_snakefield/2015_05_20_hrsfield_update.pdf q1 and septum field] <br />
| Jie<br />
<br />
|}<br />
<br />
<br />
'''Wednesday, May 13 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_05_13_simu_rad_technotes/radiation_simulation_technotes.pdf energy-loss technotes] <br />
| Jie<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/dilutionnote.pdf dilution note] <br />
| Toby<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_05_13.pdf 1.1 GeV Elastic Yields] <br />
| Melissa<br />
|}<br />
<br />
<br />
'''Wednesday, May 6 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150506/Chao_WeeklyMeeting_05062015.pdf Optics Update] <br />
| Chao<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/05062015/05062015.pdf Acceptance Update] <br />
| Min<br />
|}<br />
<br />
<br />
'''Wednesday, April 29 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/04282015/Asymmetries%20for%20different%20raster%20cut.pdf Asymmetries for different raster cut] <br />
| Pengjia<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_04_29.pdf Pf Update] <br />
| Melissa<br />
|}<br />
<br />
<br />
'''Wednesday, April 22 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/technotes/bcm_technote.pdf BCM technote draft] <br />
| Pengjia<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/qualitychecktalk.pdf Quality check summary] <br />
| Toby<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150422/Chao_WeeklyMeeting_04222015.pdf Optics Update] <br />
| Chao<br />
|}<br />
<br />
<br />
'''Wednesday, April 15 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_04_15_acc/2015_04_15_Simulation_update.pdf SIMULATION Update] <br />
| Jie<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_04_15.pdf Pf Update] <br />
| Melissa<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_041515.pdf Rad Corrections] <br />
| Ryan<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/diltalk_041515.pdf Dilution Update] <br />
| Toby<br />
|}<br />
<br />
<br />
'''Wednesday, April 8 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150408/Chao_WeeklyMeeting_04082015.pdf Optics Update] <br />
| Chao<br />
|}<br />
<br />
<br />
'''Wednesday, April 1 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_04_01.pdf PF Update] <br />
| Melissa<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_040115.pdf Model Tune] <br />
| Ryan<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/04012015/04012015.pdf Acceptance Update] <br />
| Min<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_03_31_bpmpos/2015_03_31_Simulation_update.pdf Simulation Update] <br />
| Jie<br />
|}<br />
<br />
<br />
'''Wednesday, March 25 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_03_23_rad_effects/2015_03_25_Simulation_updae.pdf Simulation_update] <br />
| Jie<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/pf_dil_talk.pdf Dilution update] <br />
| Toby<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150325/Chao_WeeklyMeeting_03252015.pdf Optics Update] <br />
| Chao<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/03252015/asym_lr.pdf asymmetry] <br />
| Pengjia<br />
|}<br />
<br />
<br />
'''Wednesday, March 18 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_03_18.pdf Packing Fraction] <br />
| Melissa<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_031715.pdf Model Tune] <br />
| Ryan<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/03182015/03182015.pdf Acceptance Update] <br />
| Min<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/03112015/ Rastercut update] <br />
| Pengjia<br />
|}<br />
<br />
<br />
'''Wednesday, March 11 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_03_06_xs_ratio/2015_03_11_Simulation_updae.pdf simulation update] <br />
| Jie<br />
|}<br />
<br />
<br />
'''Wednesday, March 4 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/diltalk_030415.pdf dilution analysis] <br />
| Toby<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_030415.pdf Model Tune] <br />
| Ryan<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_03_04.pdf Packing Fraction] <br />
| Melissa<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/03042015/03042015.pdf Acceptance Update] <br />
| Min<br />
|}<br />
<br />
<br />
'''Wednesday, February 25 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_02_24_yields/Simulation_update_2015_02_24.pdf yields study] <br />
| Jie<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/technotes/Chao_TechNote_TargetField.pdf TN: Target Field Mapping TN Draft] <br />
| Chao<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/02252015/Position_Cut_20150225.pdf position cut for yields study] <br />
| Pengjia<br />
|}<br />
<br />
<br />
'''Wednesday, February 18 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/02182015/librastercut.pdf rastercut library(not available)] <br />
| Pengjia<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/02182015/02182015.pdf Acceptance Update] <br />
| Min<br />
|}<br />
<br />
<br />
'''Wednesday, February 11 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/dilution021015.pdf Dilution update] <br />
| Toby<br />
|}<br />
<br />
<br />
'''Wednesday, February 4 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Yields/Yields_02_03.pdf Run Quality Check - RHRS] <br />
| Melissa<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150204/Chao_WeeklyMeeting_02042015.pdf RHRS Optics Update] <br />
| Chao<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_02_04_radiative/2015_02_04_Simulation_updae.pdf Simulation update] <br />
| Jie<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/02042015/02042015.pdf Acceptance Update] <br />
| Min<br />
|}<br />
<br />
<br />
'''Wednesday, January 28 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_012815.pdf 1.157 GeV Run Quality Check] <br />
| Ryan<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/01282015/yield_drift_20150128.pdf run quality check] <br />
| Pengjia<br />
|}<br />
<br />
<br />
'''Wednesday, January 21 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Yields/Yields_01_21.pdf Data Quality Check for 2.2GeV, 2.5T] <br />
| Melissa<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150121/Chao_WeeklyMeeting_01212015.pdf RHRS Optics Update] <br />
| Chao<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/01212015/01212015.pdf Acceptance Update] <br />
| Min<br />
|}<br />
<br />
<br />
'''Wednesday, January 14 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/scaler_yield_drift_talk.pdf Yield Drift Study - Scalers] <br />
| Toby<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_011415.pdf 1.157 GeV Run Quality Check] <br />
| Ryan<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_01_12_dp/Simulation_update_2015_01_12.pdf dp] <br />
| Jie<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/01152015/data_quality_20150115.pdf 1.711 GeV run quality check] <br />
| Pengjia<br />
|}<br />
<br />
<br />
'''Wednesday, January 7 2015<br />
{|border=2<br />
|-bgcolor=Grey<br />
! Topic <br />
! Presenter<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/talks/MCummingsCollabMeeting_Jan.pdf Analysis Updates] <br />
| Melissa<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150107/Chao_WeeklyMeeting_01072015.pdf Optics Update] <br />
| Chao<br />
|-<br />
| [https://userweb.jlab.org/~rbziel/CollabMeeting_12015.pdf Analysis Update] <br />
| Ryan<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/01072015/01072015.pdf Acceptance Update] <br />
| Min<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_01_06_pbosted/2015_01_06_Simulation_update.pdf simulation Update] <br />
| Jie<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/01.07.15.pdf dilution/quality check update] <br />
| Toby<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/01072015/false_asym_20150107.pdf false asymmetry] <br />
| Pengjia<br />
|-<br />
| [http://hallaweb.jlab.org/experiment/g2p/collaborators/slifer/2015/slifer_g2pcollab_010715.pdf Review]<br />
| Karl<br />
|}<br />
<br />
<br />
<br />
==2014==<br />
[[Slides_2014]]<br />
<br />
==2013==<br />
[[Slides_2013]]<br />
<br />
==2012==<br />
[[Slides_2012]]<br />
<br />
==2011==<br />
[[Slides_2011]]</div>Melissachttps://hallaweb.jlab.org/wiki/index.php?title=G2p_technotes&diff=26070G2p technotes2015-10-13T21:42:05Z<p>Melissac: /* E08-027 Technical Notes */</p>
<hr />
<div>==E08-027 Technical Notes==<br />
*[http://hallaweb.jlab.org/experiment/g2p/technotes/E08027_TN2011_01.pdf TN #01] : <I>Temperature of CH2 foil under 2.2 GeV-150nA electron beam</I>, <B>M. Defurne</B>, 2011.<br />
*[http://hallaweb.jlab.org/experiment/g2p/technotes/E08027_TN2011_02.pdf TN #02] : <I>Uncertainty on g2 due to target spin misalignment</I>, <B>P. Zhu</B>, 2011. ([http://hallaweb.jlab.org/experiment/g2p/technotes/E08027_TN2011_02.xls spreadsheet]).<br />
*[http://hallaweb.jlab.org/experiment/g2p/technotes/E08027_TN2012_03.pdf TN #03] [https://userweb.jlab.org/~rbziel/TEff_Update.pdf Update 2/11/14] : <I>Trigger Scintillator Efficiency</I>, <B>R. Zielinski</B>, 2012.<br />
*[http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/Field%20Mapping/report.pdf TN #04] : <I>Magnetic field mapping on can surface</I>, <B>T. Badman</B>, 2012.<br />
*[http://hallaweb.jlab.org/experiment/g2p/technotes/E08027_TN2013_04.pdf TN #05] : <I>Efficiency Studies and PID Cut Optimization</I>, <B>M. Cummings</B>, 2013.<br />
*[http://hallaweb.jlab.org/experiment/g2p/technotes/E08027_TN2013_05.pdf TN #06] : <I>Summary of Data Quality Checks for PID Detectors</I>, <B>M. Cummings</B>, 2013.<br />
*[http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2011_10_05_fieldmap_report/Target_Field_Map_Report.pdf TN #07] : <I>Magnetic field mapping on a translation table </I>, <B>J. Liu</B>, 2013.<br />
*[http://hallaweb.jlab.org/experiment/g2p/technotes/bpm_technote.pdf TN #08] : <I>Beam position reconstruction for g2p experiment in Hall A at Jefferson Lab</I>, <B>P. Zhu</B>, 2014.<br />
*[http://hallaweb.jlab.org/experiment/g2p/technotes/E08027_TN2013_06.pdf TN #09] : <I>Proton Polarization Studies and Uncertainty Analysis for E08-027</I>, <B>T. Badman</B>, 2013.<br />
*[http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/technote/pointingSummary.pdf TN #10] : <I>Central Scattering Angle Measurement</I>, <B>M. Huang</B>, 2014.<br />
*[https://userweb.jlab.org/~rbziel/Unpol_Rad_Final.pdf TN #11] : <I>Unpolarized Radiative Corrections</I>, <B>R. Zielinski</B>, 2014.<br />
*[https://hallaweb.jlab.org/experiment/g2p/collaborators/chao/technotes/Chao_TechNote_HelicityDecoder.pdf TN #12] : <I>Helicity Decoder for E08-027</I>, <B>C. Gu</B>, 2014.<br />
*[https://hallaweb.jlab.org/experiment/g2p/collaborators/chao/technotes/Chao_TechNote_TargetField.pdf TN #13] : <I>Target Field Mapping and Uncertainty Estimation</I>, <B>C. Gu</B>, 2015.<br />
*[http://hallaweb.jlab.org/experiment/g2p/technotes/bcm_technote.pdf TN #14] : <I>Beam Charge Measurement for g2p Experiment</I>, <B>P. Zhu</B>, 2015.<br />
*[http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2013_09_24_multi_track_notes/vdc_eff_technotes.pdf TN #15] : <I>VDC Multi-track Efficiency Study</I>, <B>J. Liu</B>, 2015.<br />
*[http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_05_13_simu_rad_technotes/radiation_simulation_technotes.pdf TN #16] : <I>Radiation Effects in Simulation</I>, <B>J. Liu</B>, 2015.<br />
*[http://hallaweb.jlab.org/experiment/g2p/technotes/E08027_TN2015_17.pdf TN #17] : <I>Packing Fraction Analysis</I>, <B>M. Cummings</B>, 2015.<br />
<br />
==Other Technotes<br />
*[https://jlabdoc.jlab.org/docushare/dsweb/Get/Document-66674/12-051.pdf JLab-TN-12-051] [http://hallaweb.jlab.org/experiment/g2p/technotes/12-051.pdf (alternate link)] : <I>Uncertainty in DNP Target Data for E08-007</I>, <B>D. Keller</B>, 2012.<br />
*[http://hallaweb.jlab.org/experiment/g2p/technotes/dXs_extraction_2nd.pdf EG4 TN] : <I>Procedure for extraction of difference of cross sections.</I>, <B>H. Kang</B>, 2011</div>Melissachttps://hallaweb.jlab.org/wiki/index.php?title=G2p_Analysis_Minutes&diff=26018G2p Analysis Minutes2015-09-29T20:22:29Z<p>Melissac: /* 9/23/2015 */</p>
<hr />
<div>Minutes of the weekly analysis meetings<br />
----<br />
[https://hallaweb.jlab.org/wiki/index.php/G2p_Weekly_Analysis Agenda]<br />
<br />
==9/23/2015==<br />
<br />
Present: JP, Kalyan, Min, Melissa <br><br />
By Phone: Pengjia, Toby, Ryan, Vince, Jie, Chao, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Pengjia<br />
**Showed the structure of his code to create a radiated model of the MAID and Bosted <br>models, based on Ryan's radiative correction work. He showed the breakdown of the <br>different components to the radiated model (internal, external and elastic tail). He used<br> the radiated model to calculate an asymmetry and cross section differences, which he <br> compared with data. Finally, he combined asymmetries calculated from data with the <br>Bosted model cross section to calculate a value for g1 and g2, which he compared <br>with values of g1/g2 determined using the MAID model. More details can be seen in <br>his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/09222015/asym_g12.pdf here].<br />
<br />
*Min<br />
**Gave an update on acceptance studies. Last time, she found that by adjusting the<br>apertures in the simulation she could match the data/simulation results for dp (for one <br>momentum setting). She tested this method for other momentum settings and found <br>that it did not work as well. She also showed a comparison of the yield spectrum for<br>helium runs in the 1.7 GeV setting; the shape of the two distributions are quite <br>different, which might suggest that the model deviates significantly form the data. In<br>the simulated results she saw several "bumps" in the yield, which correspond to the<br>location of resonances. She will update these results when the optics corrections are <br>complete. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/09232015.pdf here].<br />
<br />
<br />
<br />
'''General Discussion:'''<br />
*We would like to schedule another collaboration meeting in the near future. The <br>meeting is tentatively scheduled for Wednesday October 14th during our usual meeting <br>time (10am-12pm).<br />
*The purpose of the meeting is to:<br />
**Discuss student thesis topics (particularly any updates from the last <br>collaboration meeting)<br />
**Establish a procedure for presentation/release of collaboration plots/results<br />
*Each student should prepare a few slides (~5 minutes) to show analysis progress<br />
<br />
==9/16/2015==<br />
<br />
Present: Min, JP, Jixie, Melissa <br><br />
By Phone: Vince, Jie, Chao, Pengjia, Alex, Ryan, Toby, Ellie <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Jie<br />
**Gave an update on his simulation study using MUDIFI. Last time he showed that he uses a<br>least square fit to go from endplane to endplane. For the g2p simulation, it's used to go from<br>(x,y,&theta;,&phi;,dp) in the target plane to (x,y,&theta;,&phi;,dp) in the focal plane. SNAKE produces (x,y,&theta;,&phi;,dp)<br>data in both planes and a polynomial function can be used to determine the relationship<br>between the two planes. First the maximum power for each variable is determined, symmetries<br>are included (if applicable), then the priority of each function must be determined. A Gram-<br>Schmidt transformation is used to do the minimization, and the final step is to decide whether<br>to accept the function f<sub>i</sub>. JP/Vince asked how the priority for each function is chosen, since the<br>choice could introduce some ordering dependence. Since we don't have enough data to<br>constrain, JP suggested introducing some physics. He also suggested getting rid of dp in the<br>focal plane (since it is really just dp in the target plane) so that there is one less dimension to<br>fit. More details can be seen in Jie's slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_09_15_simulation/2015_09_15_Simulation_update.pdf here].<br />
<br />
*Ryan<br />
**Gave an update on evaluating physics quantities using models. His goal was to do a<br>comparison of the hyperfine splitting calculation in C. Carlson's 2006/2008 paper using MAID<br>and Hall B models. Previously he showed a comparison using the Hall B model, where he saw<br>good agreement between his calculation and Carlson's result. For this time he also did a<br>comparison using the MAID model. There is a large difference between the two models for the<br>value of the integrand of &Delta;<sub>2</sub>, over the full range of Q<sup>2</sup>. JP suggested comparing the value of g2<br>between the two models, instead of &Delta;<sub>2</sub>. More details can be seen in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_091615.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*Toby<br />
**Last time he showed a comparison between data and cross sections calculated using the<br>Bosted model (seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/acceptance_scatangle.pdf here]). The model was not continuous for one momentum setting. It <br>turns out the BPM was not recording for that setting, so he re-calculated the XS using<br>values for &theta; and &phi; from surrounding runs and found that the result was now consistent with<br>the neighboring momentum settings. He also played around with the acceptance cuts he<br>showed, and found a region using the "extreme cut" where the sawtooth pattern go away<br>and the yields become flat.<br />
<br />
==9/9/2015==<br />
<br />
Present: Min, JP, Jixie, Melissa <br><br />
By Phone: Vince, Jie, Chao, Ryan, Toby, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Jie<br />
**Gave an overview of his simulation study using SNAKE and MUDIFI. Using SNAKE, the<br>idea is to trace the particle trajectory in a series of free boxes, then an endplane can be<br>defined within the free boxes to determine the trajectory from endplane to endplane. In<br>g2psim this will be used to trace the trajectory between the sieve plane and the focal<br>plane. There are two important issues to consider, the magnetic field in the free boxes,<br>and the transportation method between the two endplanes. A Runge-Kutta method is <br>used for the transportation, and an adaptive method (which changes with field size and<br>gradient) is used to determine the step size. For the magnetic field, a 3D Tosca field<br>map is used for the septum, and an analytic model is used for the spectrometer magnets. <br> He also described the method for choosing the transportation function to determine the <br>25 matrix terms for each kinematic variable (up to 4th order). JP asked how to determine <br>which order is more important, and cautioned to be careful not to over fit the data. He and<br>Jie will discuss this more offline. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_09_09_simulation_update/2015_09_09_Simulation%20update.pdf here].<br />
<br />
*Chao<br />
**Gave an optics status update. The current problem is that changes in the horizontal beam<br>position changes the dp reconstruction. This was fixed by applying a linear correction in<br>BPM-x and BPM-y to &theta;, &phi; and dp. Applying this correction made the data/simulation <br>agree, but it is still necessary to understand the correction. Using dp scan data with beam<br>position scan data still leaves an offset in &theta; and &phi;. He also tried two other methods to do<br>the calibration. Method 1 uses the central hole to determine a constant offset, uses the<br>horizontal beam position scan data to determine all the matrix elements related to y, and<br>uses dp scan runs to fit the additional matrix elements. Method 2 uses beam position<br>scan data to determine the matrix elements that are not related to x<sub>fp</sub>. Neither of these<br>methods works very well, even when the fitting order of the matrix elements are adjusted.<br>He will continue to check more fitting procedures. More details can be found in his slides <br>[http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150909/Chao_WeeklyMeeting_09092015.pdf here].<br />
<br />
*Pengjia<br />
**Gave an update on comparing asymmetries from data/models for the 2.2 GeV, 5T <br>longitudinal setting. He first radiated the Bosted model XS; he showed the break down of<br>the different radiative corrections including the elastic tail (internal and external) and the<br>radiative effects from inelastic scattering. He showed a comparison with Ryan's results<br>which had good agreement, though there is some deviation when he used different proton<br>form factors (provided by Moshe). In order to compare the asymmetry result with data, he<br>needs to do the radiative corrections for the polarized MAID model, which he will continue<br>to work on. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/09092015/asym_20150909.pdf here].<br />
<br />
==9/2/2015==<br />
<br />
Present: JP, Min, Kalyan, Melissa <br><br />
By Phone: Vince, Alex, Jie, Chao, Ryan, Toby, Ellie, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Gave an update on determining the correction to asymmetries for pion contamination. <br>Previously, she used the 2.2 GeV, 5T longitudinal setting as an example, for this time <br>she used the transverse configuration, as it has the largest pion contamination. She <br>modified her method for differentiating between electrons and pions; previously she <br>identified pions as events that do not trigger the Cherenkov, this time she used a cut <br>below the single photo electron peak to select pions. JP suggested using stricter cuts <br>for selecting pions when determining the pion asymmetry, to make sure it is a clean <br>sample. Although this setting has a large pion contamination, the number of pion<br> events that remain after lead glass cuts are applied is low, so the overall correction <br>is very small. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Pion/PionAsym_08_31.pdf here].<br />
<br />
*Min<br />
**Gave an update on acceptance tuning. She looked at results from the 1.7 GeV setting <br>and found that the height of the peaks is different between data and simulation for <br>different holes in the sieve slit. Looking at the &theta; vs &phi; distribution, she noticed on the<br>positive &theta; side there were fewer holes in simulation than in data, and on the negative <br> &theta; side there were more holes in simulation compared to data. She tried adjusting the<br>aperture cuts by changing the physical location of the Q1, Q2 and septum planes to <br>uncover events that were previously blocked. After the adjustment, the data/simulation <br>results agreed much better. She showed a similar procedure for a dilution run and was<br>able to see better agreement between data/simulation after the aperture adjustments <br>were made. JP/Vince suggested being cautious when adjusting the aperture cuts, as<br> the apertures should be well defined already. They suggested adjusting things that are<br> less well known first, such as the septum field. More details can be seen in her slides<br>[http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/09022015.pdf here].<br />
<br />
*Ryan<br />
**Working on generating physics quantities using models to eventually compare with data.<br>So far, he has incorporated the MAID2007 and Hall B models. He calculated the <br>hyperfine splitting quantities &Delta;1 and &Delta;2 using the Hall B EG1 model and compared them<br> to the results in C. Carlson's 2006 paper. His results agreed very well, he only saw a<br> small deviation for &Delta;2 in the lowest Q<sup>2</sup> range. To check that nothing strange was going <br> on in the low Q<sup>2</sup> range, he calculated &Delta;2 for various small ranges around zero, to ensure<br>that the integration method is well behaved. The Carlson paper also includes calculations <br>using the Simula model, he would like to do a check of this method as well, but is unsure <br>where to find the Simula model. Since he was able to reproduce the hyperfine splitting <br>result, he is confident in his calculation method; it should be straightforward to calculate <br>other spin structure function integrals. More details on his method can be found in his <br>slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_09215.pdf here].<br />
<br />
*Toby<br />
**Showed an update on his acceptance/scattering angle study. He applied cuts of varying<br>strictness on the reconstructed &theta; vs &phi; distribution at the target. He then calculated the <br>real scattering angle before/after scattering for each cut. Using these scattering angles <br> as inputs for the Bosted model he was able to calculate the XS and compare it to data.<br>He showed the comparison between data/Bosted model for each acceptance cut. He <br>hoped that the more extreme acceptance cuts on the data would flatten the yield <br>distribution, but it actually just enhanced the sawtooth pattern. JP questioned why the <br>Bosted prediction for one momentum bin (the green one) was so much lower than the<br> neighboring ones. Toby said the only input that goes into the model is the scattering angle,<br> so it must be considerably different for this momentum setting. He also commented that<br>the model prediction is scaled to match the data, so the scaling enhances the jump in<br>the model. More details on his acceptance cuts and method can be found in his slides<br>[http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/acceptance_scatangle.pdf here].<br />
<br />
==8/26/2015==<br />
<br />
Present: Jixie, Alex, Min, Kalyan, JP, Chao, Melissa <br><br />
By Phone: Vince, Jie, Ryan, Toby, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Chao<br />
**Gave an update on optics studies. Previously, he showed a comparison between optics data <br>and simulation where he cut on individual sieve holes. For this week, he included a cut on y <br>and dp that he didn't include previously. In the plot of &theta; vs y, JP pointed out that there were <br>additional tails on some sieve holes, Chao says these tails go away when the &phi; cut is <br>included. He showed a 2D plot of &theta; vs &phi;, along with the 1D projection of these variables. JP<br>commented that the data is more smeared out than the simulation, so it is difficult to compare <br>data with simulation results. It's possible that some of the smearing comes from events that <br>punch through the sieve slit and are not being cut out (the simulation currently assumes these <br>events are stopped by the sieve). Looking at the center hole, the data/simulation agree <br>reasonably well, but the agreement gets worse for holes on the edge of the sieve slit. Chao<br>will continue to look into this. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150826/Chao_WeeklyMeeting_08262015.pdf here].<br />
**He also mentioned that ~1 month ago he reported a problem with the [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150708/Chao_WeeklyMeeting_07082015.pdf BPM simulation].<br>He found it was actually a problem with the simulation itself, which has now been updated <br> to correct the problem.<br />
<br />
<br />
'''General Discussion:'''<br />
*Pengjia has submitted his BPM NIM paper.<br />
<br />
==8/19/2015==<br />
<br />
Present: Chao, Jie, Min, Jixie, Kalyan, Melissa <br><br />
By Phone: Vince, Ryan, Toby, Karl, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Showed a method for determining the correction to asymmetries for pion contamination. The <br>measured asymmetry can be written in terms of the electron and pion asymmetries, multiplied <br>by the fraction of events of that particle. To differentiate between electrons and pions, a cut is<br>made on events that trigger the Cherenkov detector (electrons) and events that do not trigger<br>the Cherenkov (pions). Kalyan commented that this method of selecting pions may be too blind,<br> and suggested making a 2D cut on E/p vs Cherenkov instead. To determine the fraction of<br>electrons/pions, "good event" cuts are applied (loose acceptance cuts, single track events and<br>pion rejector cuts) and the number of electrons/pions that survive the cuts are counted. Although<br>the pion asymmetry is much larger than the electron asymmetry, the number of residual pions<br>is very small, so the overall correction is small. For this example the 2.2 GeV, 5T longitudinal<br>setting was used, but the correction may be larger for the 5T transverse settings, which she <br>will do next. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Pion/PionAsym_08_19.pdf here].<br />
<br />
*Min <br />
**Gave an update on acceptance studies. She used the 1.7 GeV, 2.5T setting (with 3rd septum <br>configuration) to test the acceptance cuts using the yield ratio of data to simulation. She <br>showed a plot of target &theta; vs &phi; for both data and simulation, and applied a graphical cut to get<br>rid of events on the edges. Looking at the resulting 1D plots shows reasonable agreement<br>between &theta; and &phi;. Vince pointed out that there seems to be some additional structure in the<br>dp distribution, and suggested expanding the &delta; cut out to &pm; 4% to see if there is more <br>hidden structure. Min said she has seen this in other settings as well and will look into it. She<br>also tried adjusting the cuts on &theta;, &phi; and &delta; and looked at how the ratio of yields from data/<br>simulation changed; the ratio starts to drop off as the cuts get wider. Next she will work on<br>calculating the yields using W bins. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/08192015.pdf here].<br />
<br />
==8/12/2015==<br />
<br />
Present: Jie, Chao, Kalyan, Min, Jixie, Melissa <br><br />
By Phone: Pengjia, Ryan, Toby, Karl, Ellie, Alex <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Chao<br />
**Gave an update on optics studies. Previously, Min has shown comparisons of data/simulation<br> where she looked at different columns of sieve holes. Chao continued this study by cutting on <br>individual sieve holes. Looking at the center sieve hole, the &phi; distribution looks reasonable, but <br>the &theta; distribution has some issues. Specifically, the data is wider on the left side (negative &theta;) <br>than the simulation. He showed results for several sieve holes, including one that was in the <br>row as the center hole, but in the farthest column on the left side of the sieve slit. In this case <br>the &theta; distribution had similar width for both data and simulation, but the height of the simulation<br> distribution was larger. This may suggest that something is wrong with the acceptance in the <br>simulation. The problem with &theta; seems to be systematic; for most of the sieve holes there are <br>more events on the left side of the data than in the simulation. Kalyan asked whether the <br>thickness of the sieve slit was taken into account, Chao says it was included in the simulation <br>and optimizer. Jixie suggested comparing the dp distributions for each sieve hole. More details <br>can be seen in Chao's slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150812/Chao_WeeklyMeeting_08122015.pdf here].<br />
<br />
==7/29/2015==<br />
<br />
Present: Chao, Min, JP, Melissa <br><br />
By Phone: Alex, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Min<br />
**Gave an update on acceptance studies. Previously, Chao showed a correction for the beam<br>position in g2psim. Min checked this correction by looking at optics runs. On the data she <br>applied a cut on dp (to select elastic events) and on the focal plane (to get rid of junk <br> events). On the simulation, only an aperture cut was applied. She compared the data and<br>simulation results for &theta; and &phi; both before and after drifting from the sieve slit to the target.<br>The effect of the target field on &theta; is not very large, though there is a shift down in angle.<br>However, the shape of the &theta; distribution is different between data and simulation. The<br>effect of the target field on &phi; is significant; it's not clear why this is the case. To try to<br>determine the reason for the discrepancies, she applied a cut along each column of sieve<br>slit holes in &phi; and compared the data and simulation results for &theta;,&phi; and dp. Column 2<br>seems to have the best agreement (for dp), columns 1 and 2 have a shift while columns<br>3-6 have a difference in width. Chao suggested also cutting along each row of sieve slit<br>holes to better study the effect of the drift on &phi;. Min will work on identifying the differences<br>between data and simulation, specifically whether the boundaries are different between<br>the two. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07272015/07292015.pdf here].<br />
<br />
==7/22/2015==<br />
<br />
Present: JP, Min, Jixie, Melissa <br><br />
By Phone: Alex, Ryan, Toby, Ellie, Karl, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Showed various checks for packing fraction runs that have large discrepancies, including <br>beam position, beam energy, spectrometer central momentum setting, septum current, and<br>the location of anneals. For both the 2.2 and 1.1 GeV settings, there are significant shifts in <br>the x and y beam position (2mm or more). She showed the average and standard deviation <br> of epics readings for the LHRS septum current for each run. For several runs, there are small <br>number of epics readings that drift from the average current. It's not clear if this is the <br>current is actually changing or if it is a readout problem. She will look into the yield vs time<br>to try to determine this. JP suggested making a raster cut on the center of the beam to get<br> rid of any potential scraping. Pengjia says there is a way to cut on raster size, but there will<br> be an additional BPM uncertainty. Melissa will discuss this more offline with Pengjia. More<br>details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_07_22.pdf here].<br />
<br />
*Pengjia<br />
**Gave an update on calculating asymmetries/cross sections using the MAID model. This time, <br>he used the Bosted model to get the unpolarized cross sections for the proton. Using unradiated <br>cross section models, he still saw a factor of 6 difference when compared with data. Ryan also <br>calculated asymmetries using unradiated models, and the results were consistent with Pengjia's, <br>so it seems the radiative effects contribute significantly to the factor of 6 difference. More <br>details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07222015/MAID_update_20150722.pdf here].<br />
<br />
==7/15/2015==<br />
<br />
Present: JP, Min, Chao, Jixie, Melissa <br><br />
By Phone: Ryan, Toby, Ellie, Karl, Vince, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Chao<br />
**Doing a check of simulation/data results for the 2.2 GeV, longitudinal setting in order <br>to check that the optics calibration matrix will work for all momentum settings (not <br>just elastic). He showed a comparison for several different momentum settings.<br> Vince suggested simulating more events, since the statistics start to drop off for <br>lower momentum settings. In general, the data is broader then the result from<br>simulation. In the &theta; distribution, the "tails" seen in the data are not symmetric. JP<br> suggested carefully selecting cuts to remove any background from the data to <br>ensure a good comparison with simulation. More details can be seen in his <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150715/Chao_WeeklyMeeting_07152015.pdf here].<br />
<br />
*Pengjia<br />
**More discussion on Pengjia's [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07082015/MAID_update_20150708.pdf slides] from last week. Pengjia has seen a factor of <br>six difference between his asymmetry calculated from data compared to the <br>asymmetry determined using the MAID model. Ryan did not see this factor of six <br>in his study, but in addition to using radiated XS models, he is using a combination <br>of the Bosted and MAID models (Pengjia is using just the MAID model). Karl <br>commented that the XS from MAID is not very good for our kinematics. Pengjia <br>also showed an estimated NH3 XS. JP commented that it was surprising that the <br>delta peak wasn't visible. Pengjia will look into this for next time.<br />
<br />
==7/8/2015==<br />
<br />
Present: JP, Min, Chao, Melissa <br><br />
By Phone: Toby, Vince <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Pengjia<br />
**Working on comparing asymmetries determined from MAID to those calculated from <br>data; last time he showed a factor of 6 difference between the two results. This <br>time, he showed two different methods for calculating the differential XS from the <br>virtual photon XS. The first method calculates the differential XS directly from <br>the virtual photon XS, and the second method calculates the differential XS using <br>F<sub>1</sub>, F<sub>2</sub>, g<sub>1</sub> and g<sub>2</sub>. He also showed two different methods for calculating the <br>asymmetry from the virtual photon XS; one method uses A<sub>1</sub> and A<sub>2</sub>, while the other <br>is calculated from the virtual photon XS. There was a discrepancy between the two <br>methods, but he found that there was actually a mistake in one of the equations. <br>While the results from the two methods agree with each other, they are still a factor <br>of 6 larger than the results from data. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07082015/MAID_update_20150708.pdf here].<br />
<br />
*Toby<br />
**Showed an update of his scattering angle study for model reconstruction. He is <br>using BPM and optics data to determine the scattering angle. He showed an example <br>of the calculated scattering angle; JP questioned whether the range was really from <br>0-16 deg. Toby pointed out that there really aren't many events at the boundaries, <br>the distribution is peaked between 4.5-9 deg. He then uses this scattering angle as<br>input for the Bosted model. At low &nu; the simulation results match reasonably well<br>with the data, but the discrepancy starts to become larger as &nu; increases. He took <br>a closer look at the reconstructed scattering angle for each central momentum, and <br>found that a second peak is visible for smaller values of p0. If this second peak was <br>real, the simulation should recreate the data, so this could suggest a problem with <br>the reconstruction. However, Chao pointed out that, for this energy setting, the optics <br>calibration is not complete (currently using the longitudinal optics matrix), so the <br>reconstructed &theta; and &phi; may not be correct yet. For next time, Toby will test this <br>analysis using the 1.7 GeV setting, which has calibrated optics. More details can <br> be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/scatangle_talk.pdf here].<br />
<br />
*Melissa<br />
**Gave a summary of packing fraction analysis. For some settings, the variation in the <br>yields (and P<sub>f</sub>) is due to a fluctuation in the beam position. This will hopefully be<br>resolved by Jie's beam position/acceptance study. For the 2.2 GeV, 2.5T transverse setting<br> there is also an issue of a shift in &nu; between runs. For the 1.1 GeV, 2.5T transverse <br>setting, the yields vary depending on the beam current used for each run. JP suggested <br>a few things to check as the possible cause for these discrepancies including drift in the <br>BCM calibration, anneals of the target material, drift in field (HRS or septum), etc. She <br>has posted a technote draft [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Technotes/PF_technote_draft.pdf here], feedback would be appreciated. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_07_08.pdf here].<br />
<br />
*Min<br />
**Gave an update on her acceptance study. Last time, she showed that the simulation results <br>are more narrow than the data. For this time, she tried cutting on just the center hole, <br>and found that the dp distribution from data better matched the simulation. JP suggested <br>cutting on each of the different holes individually to determine which hole causes the dp <br>distribution to be wider. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07082015/07062015.pdf here].<br />
<br />
*Chao<br />
**Gave an update on optics analysis, currently checking whether simulation results match <br>with data, starting with optics data. First he checked whether the geometry was correct, <br>some deviation was found in the recent optics meeting. The position of the BPMs is hard-<br>coded into the simulation, and the drifting algorithm is used to drift the electrons <br>backward to the BPMs to simulate the readout of BPM A and B. He compared the &theta; <br>distribution before drifting in the target field using a fixed and non-fixed BPM location. <br>The results using a fixed BPM match well with the data. He is currently working on <br>checking this for all momentum settings, and will follow up with Pengjia about the BPM <br>problem. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150708/Chao_WeeklyMeeting_07082015.pdf here].<br />
<br />
==7/1/2015==<br />
<br />
Present: Chao, Vince, Jie, JP, Min, Melissa <br><br />
By Phone: Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Min<br />
**Gave an update on acceptance studies. She showed a summary table of each energy <br>setting and septum configuration. There hasn't been any problems in the 2.2 GeV, 5T <br>longitudinal and 1.7 GeV, 2.5T transverse settings, but some settings (2.2 GeV, 2.5T <br> transverse, 1.2 GeV, 2.5T transverse and 2.2 GeV, 5T transverse) have a discrepancy <br>in the focal plane between data and simulation. She compared the data divided by the <br>Mott XS to the simulation results without XS, and found that the simulation results <br>of &theta; and &phi; are narrower then the data. JP commented that, while including the Mott<br>XS might change the shape of the distribution, it shouldn't change the boundary. She <br>work on figuring out the cause for this discrepancy before calculating the acceptance. <br>More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07012015/07012015.pdf here].<br />
<br />
*Pengjia<br />
**Comparing asymmetries determined from the MAID model to those calculated from data.<br>Last time he showed a factor of 6 difference between the two results. He determined the <br>scattering angle and Q<sup>2</sup> by fitting the data and compared them to the quantities calculated <br>from MAID. He also showed the results of calculating the quantities g<sub>1</sub>, g<sub>2</sub>, F<sub>1</sub>, F<sub>2</sub>, A<sub>L</sub>, A<sub>T</sub>,<br> dXS<sub>L</sub>, dXS<sub>T</sub>, XS<sub>tot</sub> andXS<sub>mott</sub> using MAID. He hasn't included radiative corrections in his <br>calculations, but this probably won't account for the factor of 6. More details can be seen <br>in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07012015/MAID_20150701.pdf here].<br />
<br />
<br />
----<br />
<br />
==Jan-June 2015==<br />
[[Minutes_Jan2015_to_June2015]]<br />
----<br />
<br />
==July-Dec 2014==<br />
[[Minutes_July2014_to_Dec2014]]<br />
----<br />
<br />
==Jan-June 2014==<br />
[[Minutes_Jan2014_to_June2014]]<br />
----<br />
<br />
==June-Dec 2013==<br />
[[Minutes_June2013_to_Dec2013]]<br />
----<br />
<br />
==Jan-May 2013==<br />
[[Minutes_Jan2013_to_May2013]]<br />
----<br />
<br />
==April-Dec 2012==<br />
[[Minutes_Apr2012_to_Dec2012]]<br />
----<br />
<br />
==Jan-March 2012==<br />
[[Minutes_Jan2012_to_Mar2012]]<br />
----<br />
==July-Dec 2011==<br />
[[Minutes_July2011_to_Dec_2011]]<br />
----<br />
==Jan-June 2011==<br />
[[Minutes_Jan2011_to_June_2011]]<br />
----</div>Melissachttps://hallaweb.jlab.org/wiki/index.php?title=G2p_Analysis_Minutes&diff=25971G2p Analysis Minutes2015-09-25T02:40:46Z<p>Melissac: /* 9/16/2015 */</p>
<hr />
<div>Minutes of the weekly analysis meetings<br />
----<br />
[https://hallaweb.jlab.org/wiki/index.php/G2p_Weekly_Analysis Agenda]<br />
<br />
==9/23/2015==<br />
<br />
Present: JP, Kalyan, Min, Melissa <br><br />
By Phone: Pengjia, Toby, Ryan, Vince, Jie, Chao, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Pengjia<br />
**Showed the structure of his code to create a radiated model of the MAID and Bosted <br>models, based on Ryan's radiative correction work. He showed the breakdown of the <br>different components to the radiated model (internal, external and elastic tail). He used<br> the radiated model to calculate an asymmetry and cross section differences, which he <br> compared with data. Finally, he combined asymmetries calculated from data with the <br>Bosted model cross section to calculate a value for g1 and g2, which he compared <br>with values of g1/g2 determined using the MAID model. More details can be seen in <br>his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/09222015/asym_g12.pdf here].<br />
<br />
*Min<br />
**Gave an update on acceptance studies. Last time, she found that by adjusting the<br>apertures in the simulation she could match the data/simulation results for dp (for one <br>momentum setting). She tested this method for other momentum settings and found <br>that it did not work as well. She also showed a comparison of the yield spectrum for<br>helium runs in the 1.7 GeV setting; the shape of the two distributions are quite <br>different, which might suggest that the model deviates significantly form the data. In<br>the simulated results she saw several "bumps" in the yield, which correspond to the<br>location of resonances. She will update these results when the optics corrections are <br>complete. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/09232015.pdf here].<br />
<br />
<br />
<br />
'''General Discussion:'''<br />
*We would like to schedule another collaboration meeting to discuss thesis topics. The <br>meeting is tentatively scheduled for Wednesday October 14th during our usual meeting <br>time (10am-12pm). <br />
<br />
<br />
<br />
==9/16/2015==<br />
<br />
Present: Min, JP, Jixie, Melissa <br><br />
By Phone: Vince, Jie, Chao, Pengjia, Alex, Ryan, Toby, Ellie <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Jie<br />
**Gave an update on his simulation study using MUDIFI. Last time he showed that he uses a<br>least square fit to go from endplane to endplane. For the g2p simulation, it's used to go from<br>(x,y,&theta;,&phi;,dp) in the target plane to (x,y,&theta;,&phi;,dp) in the focal plane. SNAKE produces (x,y,&theta;,&phi;,dp)<br>data in both planes and a polynomial function can be used to determine the relationship<br>between the two planes. First the maximum power for each variable is determined, symmetries<br>are included (if applicable), then the priority of each function must be determined. A Gram-<br>Schmidt transformation is used to do the minimization, and the final step is to decide whether<br>to accept the function f<sub>i</sub>. JP/Vince asked how the priority for each function is chosen, since the<br>choice could introduce some ordering dependence. Since we don't have enough data to<br>constrain, JP suggested introducing some physics. He also suggested getting rid of dp in the<br>focal plane (since it is really just dp in the target plane) so that there is one less dimension to<br>fit. More details can be seen in Jie's slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_09_15_simulation/2015_09_15_Simulation_update.pdf here].<br />
<br />
*Ryan<br />
**Gave an update on evaluating physics quantities using models. His goal was to do a<br>comparison of the hyperfine splitting calculation in C. Carlson's 2006/2008 paper using MAID<br>and Hall B models. Previously he showed a comparison using the Hall B model, where he saw<br>good agreement between his calculation and Carlson's result. For this time he also did a<br>comparison using the MAID model. There is a large difference between the two models for the<br>value of the integrand of &Delta;<sub>2</sub>, over the full range of Q<sup>2</sup>. JP suggested comparing the value of g2<br>between the two models, instead of &Delta;<sub>2</sub>. More details can be seen in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_091615.pdf here].<br />
<br />
<br />
'''General Discussion:'''<br />
*Toby<br />
**Last time he showed a comparison between data and cross sections calculated using the<br>Bosted model (seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/acceptance_scatangle.pdf here]). The model was not continuous for one momentum setting. It <br>turns out the BPM was not recording for that setting, so he re-calculated the XS using<br>values for &theta; and &phi; from surrounding runs and found that the result was now consistent with<br>the neighboring momentum settings. He also played around with the acceptance cuts he<br>showed, and found a region using the "extreme cut" where the sawtooth pattern go away<br>and the yields become flat.<br />
<br />
==9/9/2015==<br />
<br />
Present: Min, JP, Jixie, Melissa <br><br />
By Phone: Vince, Jie, Chao, Ryan, Toby, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Jie<br />
**Gave an overview of his simulation study using SNAKE and MUDIFI. Using SNAKE, the<br>idea is to trace the particle trajectory in a series of free boxes, then an endplane can be<br>defined within the free boxes to determine the trajectory from endplane to endplane. In<br>g2psim this will be used to trace the trajectory between the sieve plane and the focal<br>plane. There are two important issues to consider, the magnetic field in the free boxes,<br>and the transportation method between the two endplanes. A Runge-Kutta method is <br>used for the transportation, and an adaptive method (which changes with field size and<br>gradient) is used to determine the step size. For the magnetic field, a 3D Tosca field<br>map is used for the septum, and an analytic model is used for the spectrometer magnets. <br> He also described the method for choosing the transportation function to determine the <br>25 matrix terms for each kinematic variable (up to 4th order). JP asked how to determine <br>which order is more important, and cautioned to be careful not to over fit the data. He and<br>Jie will discuss this more offline. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_09_09_simulation_update/2015_09_09_Simulation%20update.pdf here].<br />
<br />
*Chao<br />
**Gave an optics status update. The current problem is that changes in the horizontal beam<br>position changes the dp reconstruction. This was fixed by applying a linear correction in<br>BPM-x and BPM-y to &theta;, &phi; and dp. Applying this correction made the data/simulation <br>agree, but it is still necessary to understand the correction. Using dp scan data with beam<br>position scan data still leaves an offset in &theta; and &phi;. He also tried two other methods to do<br>the calibration. Method 1 uses the central hole to determine a constant offset, uses the<br>horizontal beam position scan data to determine all the matrix elements related to y, and<br>uses dp scan runs to fit the additional matrix elements. Method 2 uses beam position<br>scan data to determine the matrix elements that are not related to x<sub>fp</sub>. Neither of these<br>methods works very well, even when the fitting order of the matrix elements are adjusted.<br>He will continue to check more fitting procedures. More details can be found in his slides <br>[http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150909/Chao_WeeklyMeeting_09092015.pdf here].<br />
<br />
*Pengjia<br />
**Gave an update on comparing asymmetries from data/models for the 2.2 GeV, 5T <br>longitudinal setting. He first radiated the Bosted model XS; he showed the break down of<br>the different radiative corrections including the elastic tail (internal and external) and the<br>radiative effects from inelastic scattering. He showed a comparison with Ryan's results<br>which had good agreement, though there is some deviation when he used different proton<br>form factors (provided by Moshe). In order to compare the asymmetry result with data, he<br>needs to do the radiative corrections for the polarized MAID model, which he will continue<br>to work on. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/09092015/asym_20150909.pdf here].<br />
<br />
==9/2/2015==<br />
<br />
Present: JP, Min, Kalyan, Melissa <br><br />
By Phone: Vince, Alex, Jie, Chao, Ryan, Toby, Ellie, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Gave an update on determining the correction to asymmetries for pion contamination. <br>Previously, she used the 2.2 GeV, 5T longitudinal setting as an example, for this time <br>she used the transverse configuration, as it has the largest pion contamination. She <br>modified her method for differentiating between electrons and pions; previously she <br>identified pions as events that do not trigger the Cherenkov, this time she used a cut <br>below the single photo electron peak to select pions. JP suggested using stricter cuts <br>for selecting pions when determining the pion asymmetry, to make sure it is a clean <br>sample. Although this setting has a large pion contamination, the number of pion<br> events that remain after lead glass cuts are applied is low, so the overall correction <br>is very small. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Pion/PionAsym_08_31.pdf here].<br />
<br />
*Min<br />
**Gave an update on acceptance tuning. She looked at results from the 1.7 GeV setting <br>and found that the height of the peaks is different between data and simulation for <br>different holes in the sieve slit. Looking at the &theta; vs &phi; distribution, she noticed on the<br>positive &theta; side there were fewer holes in simulation than in data, and on the negative <br> &theta; side there were more holes in simulation compared to data. She tried adjusting the<br>aperture cuts by changing the physical location of the Q1, Q2 and septum planes to <br>uncover events that were previously blocked. After the adjustment, the data/simulation <br>results agreed much better. She showed a similar procedure for a dilution run and was<br>able to see better agreement between data/simulation after the aperture adjustments <br>were made. JP/Vince suggested being cautious when adjusting the aperture cuts, as<br> the apertures should be well defined already. They suggested adjusting things that are<br> less well known first, such as the septum field. More details can be seen in her slides<br>[http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/09022015.pdf here].<br />
<br />
*Ryan<br />
**Working on generating physics quantities using models to eventually compare with data.<br>So far, he has incorporated the MAID2007 and Hall B models. He calculated the <br>hyperfine splitting quantities &Delta;1 and &Delta;2 using the Hall B EG1 model and compared them<br> to the results in C. Carlson's 2006 paper. His results agreed very well, he only saw a<br> small deviation for &Delta;2 in the lowest Q<sup>2</sup> range. To check that nothing strange was going <br> on in the low Q<sup>2</sup> range, he calculated &Delta;2 for various small ranges around zero, to ensure<br>that the integration method is well behaved. The Carlson paper also includes calculations <br>using the Simula model, he would like to do a check of this method as well, but is unsure <br>where to find the Simula model. Since he was able to reproduce the hyperfine splitting <br>result, he is confident in his calculation method; it should be straightforward to calculate <br>other spin structure function integrals. More details on his method can be found in his <br>slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_09215.pdf here].<br />
<br />
*Toby<br />
**Showed an update on his acceptance/scattering angle study. He applied cuts of varying<br>strictness on the reconstructed &theta; vs &phi; distribution at the target. He then calculated the <br>real scattering angle before/after scattering for each cut. Using these scattering angles <br> as inputs for the Bosted model he was able to calculate the XS and compare it to data.<br>He showed the comparison between data/Bosted model for each acceptance cut. He <br>hoped that the more extreme acceptance cuts on the data would flatten the yield <br>distribution, but it actually just enhanced the sawtooth pattern. JP questioned why the <br>Bosted prediction for one momentum bin (the green one) was so much lower than the<br> neighboring ones. Toby said the only input that goes into the model is the scattering angle,<br> so it must be considerably different for this momentum setting. He also commented that<br>the model prediction is scaled to match the data, so the scaling enhances the jump in<br>the model. More details on his acceptance cuts and method can be found in his slides<br>[http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/acceptance_scatangle.pdf here].<br />
<br />
==8/26/2015==<br />
<br />
Present: Jixie, Alex, Min, Kalyan, JP, Chao, Melissa <br><br />
By Phone: Vince, Jie, Ryan, Toby, Karl <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Chao<br />
**Gave an update on optics studies. Previously, he showed a comparison between optics data <br>and simulation where he cut on individual sieve holes. For this week, he included a cut on y <br>and dp that he didn't include previously. In the plot of &theta; vs y, JP pointed out that there were <br>additional tails on some sieve holes, Chao says these tails go away when the &phi; cut is <br>included. He showed a 2D plot of &theta; vs &phi;, along with the 1D projection of these variables. JP<br>commented that the data is more smeared out than the simulation, so it is difficult to compare <br>data with simulation results. It's possible that some of the smearing comes from events that <br>punch through the sieve slit and are not being cut out (the simulation currently assumes these <br>events are stopped by the sieve). Looking at the center hole, the data/simulation agree <br>reasonably well, but the agreement gets worse for holes on the edge of the sieve slit. Chao<br>will continue to look into this. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150826/Chao_WeeklyMeeting_08262015.pdf here].<br />
**He also mentioned that ~1 month ago he reported a problem with the [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150708/Chao_WeeklyMeeting_07082015.pdf BPM simulation].<br>He found it was actually a problem with the simulation itself, which has now been updated <br> to correct the problem.<br />
<br />
<br />
'''General Discussion:'''<br />
*Pengjia has submitted his BPM NIM paper.<br />
<br />
==8/19/2015==<br />
<br />
Present: Chao, Jie, Min, Jixie, Kalyan, Melissa <br><br />
By Phone: Vince, Ryan, Toby, Karl, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Showed a method for determining the correction to asymmetries for pion contamination. The <br>measured asymmetry can be written in terms of the electron and pion asymmetries, multiplied <br>by the fraction of events of that particle. To differentiate between electrons and pions, a cut is<br>made on events that trigger the Cherenkov detector (electrons) and events that do not trigger<br>the Cherenkov (pions). Kalyan commented that this method of selecting pions may be too blind,<br> and suggested making a 2D cut on E/p vs Cherenkov instead. To determine the fraction of<br>electrons/pions, "good event" cuts are applied (loose acceptance cuts, single track events and<br>pion rejector cuts) and the number of electrons/pions that survive the cuts are counted. Although<br>the pion asymmetry is much larger than the electron asymmetry, the number of residual pions<br>is very small, so the overall correction is small. For this example the 2.2 GeV, 5T longitudinal<br>setting was used, but the correction may be larger for the 5T transverse settings, which she <br>will do next. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Pion/PionAsym_08_19.pdf here].<br />
<br />
*Min <br />
**Gave an update on acceptance studies. She used the 1.7 GeV, 2.5T setting (with 3rd septum <br>configuration) to test the acceptance cuts using the yield ratio of data to simulation. She <br>showed a plot of target &theta; vs &phi; for both data and simulation, and applied a graphical cut to get<br>rid of events on the edges. Looking at the resulting 1D plots shows reasonable agreement<br>between &theta; and &phi;. Vince pointed out that there seems to be some additional structure in the<br>dp distribution, and suggested expanding the &delta; cut out to &pm; 4% to see if there is more <br>hidden structure. Min said she has seen this in other settings as well and will look into it. She<br>also tried adjusting the cuts on &theta;, &phi; and &delta; and looked at how the ratio of yields from data/<br>simulation changed; the ratio starts to drop off as the cuts get wider. Next she will work on<br>calculating the yields using W bins. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/08192015.pdf here].<br />
<br />
==8/12/2015==<br />
<br />
Present: Jie, Chao, Kalyan, Min, Jixie, Melissa <br><br />
By Phone: Pengjia, Ryan, Toby, Karl, Ellie, Alex <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Chao<br />
**Gave an update on optics studies. Previously, Min has shown comparisons of data/simulation<br> where she looked at different columns of sieve holes. Chao continued this study by cutting on <br>individual sieve holes. Looking at the center sieve hole, the &phi; distribution looks reasonable, but <br>the &theta; distribution has some issues. Specifically, the data is wider on the left side (negative &theta;) <br>than the simulation. He showed results for several sieve holes, including one that was in the <br>row as the center hole, but in the farthest column on the left side of the sieve slit. In this case <br>the &theta; distribution had similar width for both data and simulation, but the height of the simulation<br> distribution was larger. This may suggest that something is wrong with the acceptance in the <br>simulation. The problem with &theta; seems to be systematic; for most of the sieve holes there are <br>more events on the left side of the data than in the simulation. Kalyan asked whether the <br>thickness of the sieve slit was taken into account, Chao says it was included in the simulation <br>and optimizer. Jixie suggested comparing the dp distributions for each sieve hole. More details <br>can be seen in Chao's slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150812/Chao_WeeklyMeeting_08122015.pdf here].<br />
<br />
==7/29/2015==<br />
<br />
Present: Chao, Min, JP, Melissa <br><br />
By Phone: Alex, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Min<br />
**Gave an update on acceptance studies. Previously, Chao showed a correction for the beam<br>position in g2psim. Min checked this correction by looking at optics runs. On the data she <br>applied a cut on dp (to select elastic events) and on the focal plane (to get rid of junk <br> events). On the simulation, only an aperture cut was applied. She compared the data and<br>simulation results for &theta; and &phi; both before and after drifting from the sieve slit to the target.<br>The effect of the target field on &theta; is not very large, though there is a shift down in angle.<br>However, the shape of the &theta; distribution is different between data and simulation. The<br>effect of the target field on &phi; is significant; it's not clear why this is the case. To try to<br>determine the reason for the discrepancies, she applied a cut along each column of sieve<br>slit holes in &phi; and compared the data and simulation results for &theta;,&phi; and dp. Column 2<br>seems to have the best agreement (for dp), columns 1 and 2 have a shift while columns<br>3-6 have a difference in width. Chao suggested also cutting along each row of sieve slit<br>holes to better study the effect of the drift on &phi;. Min will work on identifying the differences<br>between data and simulation, specifically whether the boundaries are different between<br>the two. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07272015/07292015.pdf here].<br />
<br />
==7/22/2015==<br />
<br />
Present: JP, Min, Jixie, Melissa <br><br />
By Phone: Alex, Ryan, Toby, Ellie, Karl, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Melissa<br />
**Showed various checks for packing fraction runs that have large discrepancies, including <br>beam position, beam energy, spectrometer central momentum setting, septum current, and<br>the location of anneals. For both the 2.2 and 1.1 GeV settings, there are significant shifts in <br>the x and y beam position (2mm or more). She showed the average and standard deviation <br> of epics readings for the LHRS septum current for each run. For several runs, there are small <br>number of epics readings that drift from the average current. It's not clear if this is the <br>current is actually changing or if it is a readout problem. She will look into the yield vs time<br>to try to determine this. JP suggested making a raster cut on the center of the beam to get<br> rid of any potential scraping. Pengjia says there is a way to cut on raster size, but there will<br> be an additional BPM uncertainty. Melissa will discuss this more offline with Pengjia. More<br>details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_07_22.pdf here].<br />
<br />
*Pengjia<br />
**Gave an update on calculating asymmetries/cross sections using the MAID model. This time, <br>he used the Bosted model to get the unpolarized cross sections for the proton. Using unradiated <br>cross section models, he still saw a factor of 6 difference when compared with data. Ryan also <br>calculated asymmetries using unradiated models, and the results were consistent with Pengjia's, <br>so it seems the radiative effects contribute significantly to the factor of 6 difference. More <br>details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07222015/MAID_update_20150722.pdf here].<br />
<br />
==7/15/2015==<br />
<br />
Present: JP, Min, Chao, Jixie, Melissa <br><br />
By Phone: Ryan, Toby, Ellie, Karl, Vince, Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Chao<br />
**Doing a check of simulation/data results for the 2.2 GeV, longitudinal setting in order <br>to check that the optics calibration matrix will work for all momentum settings (not <br>just elastic). He showed a comparison for several different momentum settings.<br> Vince suggested simulating more events, since the statistics start to drop off for <br>lower momentum settings. In general, the data is broader then the result from<br>simulation. In the &theta; distribution, the "tails" seen in the data are not symmetric. JP<br> suggested carefully selecting cuts to remove any background from the data to <br>ensure a good comparison with simulation. More details can be seen in his <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150715/Chao_WeeklyMeeting_07152015.pdf here].<br />
<br />
*Pengjia<br />
**More discussion on Pengjia's [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07082015/MAID_update_20150708.pdf slides] from last week. Pengjia has seen a factor of <br>six difference between his asymmetry calculated from data compared to the <br>asymmetry determined using the MAID model. Ryan did not see this factor of six <br>in his study, but in addition to using radiated XS models, he is using a combination <br>of the Bosted and MAID models (Pengjia is using just the MAID model). Karl <br>commented that the XS from MAID is not very good for our kinematics. Pengjia <br>also showed an estimated NH3 XS. JP commented that it was surprising that the <br>delta peak wasn't visible. Pengjia will look into this for next time.<br />
<br />
==7/8/2015==<br />
<br />
Present: JP, Min, Chao, Melissa <br><br />
By Phone: Toby, Vince <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Pengjia<br />
**Working on comparing asymmetries determined from MAID to those calculated from <br>data; last time he showed a factor of 6 difference between the two results. This <br>time, he showed two different methods for calculating the differential XS from the <br>virtual photon XS. The first method calculates the differential XS directly from <br>the virtual photon XS, and the second method calculates the differential XS using <br>F<sub>1</sub>, F<sub>2</sub>, g<sub>1</sub> and g<sub>2</sub>. He also showed two different methods for calculating the <br>asymmetry from the virtual photon XS; one method uses A<sub>1</sub> and A<sub>2</sub>, while the other <br>is calculated from the virtual photon XS. There was a discrepancy between the two <br>methods, but he found that there was actually a mistake in one of the equations. <br>While the results from the two methods agree with each other, they are still a factor <br>of 6 larger than the results from data. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07082015/MAID_update_20150708.pdf here].<br />
<br />
*Toby<br />
**Showed an update of his scattering angle study for model reconstruction. He is <br>using BPM and optics data to determine the scattering angle. He showed an example <br>of the calculated scattering angle; JP questioned whether the range was really from <br>0-16 deg. Toby pointed out that there really aren't many events at the boundaries, <br>the distribution is peaked between 4.5-9 deg. He then uses this scattering angle as<br>input for the Bosted model. At low &nu; the simulation results match reasonably well<br>with the data, but the discrepancy starts to become larger as &nu; increases. He took <br>a closer look at the reconstructed scattering angle for each central momentum, and <br>found that a second peak is visible for smaller values of p0. If this second peak was <br>real, the simulation should recreate the data, so this could suggest a problem with <br>the reconstruction. However, Chao pointed out that, for this energy setting, the optics <br>calibration is not complete (currently using the longitudinal optics matrix), so the <br>reconstructed &theta; and &phi; may not be correct yet. For next time, Toby will test this <br>analysis using the 1.7 GeV setting, which has calibrated optics. More details can <br> be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/scatangle_talk.pdf here].<br />
<br />
*Melissa<br />
**Gave a summary of packing fraction analysis. For some settings, the variation in the <br>yields (and P<sub>f</sub>) is due to a fluctuation in the beam position. This will hopefully be<br>resolved by Jie's beam position/acceptance study. For the 2.2 GeV, 2.5T transverse setting<br> there is also an issue of a shift in &nu; between runs. For the 1.1 GeV, 2.5T transverse <br>setting, the yields vary depending on the beam current used for each run. JP suggested <br>a few things to check as the possible cause for these discrepancies including drift in the <br>BCM calibration, anneals of the target material, drift in field (HRS or septum), etc. She <br>has posted a technote draft [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Technotes/PF_technote_draft.pdf here], feedback would be appreciated. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_07_08.pdf here].<br />
<br />
*Min<br />
**Gave an update on her acceptance study. Last time, she showed that the simulation results <br>are more narrow than the data. For this time, she tried cutting on just the center hole, <br>and found that the dp distribution from data better matched the simulation. JP suggested <br>cutting on each of the different holes individually to determine which hole causes the dp <br>distribution to be wider. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07082015/07062015.pdf here].<br />
<br />
*Chao<br />
**Gave an update on optics analysis, currently checking whether simulation results match <br>with data, starting with optics data. First he checked whether the geometry was correct, <br>some deviation was found in the recent optics meeting. The position of the BPMs is hard-<br>coded into the simulation, and the drifting algorithm is used to drift the electrons <br>backward to the BPMs to simulate the readout of BPM A and B. He compared the &theta; <br>distribution before drifting in the target field using a fixed and non-fixed BPM location. <br>The results using a fixed BPM match well with the data. He is currently working on <br>checking this for all momentum settings, and will follow up with Pengjia about the BPM <br>problem. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150708/Chao_WeeklyMeeting_07082015.pdf here].<br />
<br />
==7/1/2015==<br />
<br />
Present: Chao, Vince, Jie, JP, Min, Melissa <br><br />
By Phone: Pengjia <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Min<br />
**Gave an update on acceptance studies. She showed a summary table of each energy <br>setting and septum configuration. There hasn't been any problems in the 2.2 GeV, 5T <br>longitudinal and 1.7 GeV, 2.5T transverse settings, but some settings (2.2 GeV, 2.5T <br> transverse, 1.2 GeV, 2.5T transverse and 2.2 GeV, 5T transverse) have a discrepancy <br>in the focal plane between data and simulation. She compared the data divided by the <br>Mott XS to the simulation results without XS, and found that the simulation results <br>of &theta; and &phi; are narrower then the data. JP commented that, while including the Mott<br>XS might change the shape of the distribution, it shouldn't change the boundary. She <br>work on figuring out the cause for this discrepancy before calculating the acceptance. <br>More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07012015/07012015.pdf here].<br />
<br />
*Pengjia<br />
**Comparing asymmetries determined from the MAID model to those calculated from data.<br>Last time he showed a factor of 6 difference between the two results. He determined the <br>scattering angle and Q<sup>2</sup> by fitting the data and compared them to the quantities calculated <br>from MAID. He also showed the results of calculating the quantities g<sub>1</sub>, g<sub>2</sub>, F<sub>1</sub>, F<sub>2</sub>, A<sub>L</sub>, A<sub>T</sub>,<br> dXS<sub>L</sub>, dXS<sub>T</sub>, XS<sub>tot</sub> andXS<sub>mott</sub> using MAID. He hasn't included radiative corrections in his <br>calculations, but this probably won't account for the factor of 6. More details can be seen <br>in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07012015/MAID_20150701.pdf here].<br />
<br />
<br />
----<br />
<br />
==Jan-June 2015==<br />
[[Minutes_Jan2015_to_June2015]]<br />
----<br />
<br />
==July-Dec 2014==<br />
[[Minutes_July2014_to_Dec2014]]<br />
----<br />
<br />
==Jan-June 2014==<br />
[[Minutes_Jan2014_to_June2014]]<br />
----<br />
<br />
==June-Dec 2013==<br />
[[Minutes_June2013_to_Dec2013]]<br />
----<br />
<br />
==Jan-May 2013==<br />
[[Minutes_Jan2013_to_May2013]]<br />
----<br />
<br />
==April-Dec 2012==<br />
[[Minutes_Apr2012_to_Dec2012]]<br />
----<br />
<br />
==Jan-March 2012==<br />
[[Minutes_Jan2012_to_Mar2012]]<br />
----<br />
==July-Dec 2011==<br />
[[Minutes_July2011_to_Dec_2011]]<br />
----<br />
==Jan-June 2011==<br />
[[Minutes_Jan2011_to_June_2011]]<br />
----</div>Melissachttps://hallaweb.jlab.org/wiki/index.php?title=G2p_Analysis_Minutes&diff=25918G2p Analysis Minutes2015-09-18T01:35:48Z<p>Melissac: /* 9/16/2015 */</p>
<hr />
<div>Minutes of the weekly analysis meetings<br />
----<br />
[https://hallaweb.jlab.org/wiki/index.php/G2p_Weekly_Analysis Agenda]<br />
<br />
==9/16/2015==<br />
<br />
Present: Min, JP, Jixie, Melissa <br><br />
By Phone: Vince, Jie, Chao, Pengjia, Alex, Ryan, Toby, Ellie <br><br />
<br />
'''Feature Presentations:'''<br />
<br />
*Jie<br />
**Gave an update on his simulation study using MUDIFI. Last time he showed that he uses a&