View source for Minutes June2013 to Dec2013

==12/11/2013==

Present: Kalyan, JP, Chao, Min, Jie, Melissa <br>
By Phone: Ellie, Toby, Ryan, Karl, Alexandre, Moshe, Pengjia<br>


'''Feature Presentations:'''

*Ryan: 
**Working on comparing elastic cross sections for carbon and nitrogen using form factor data.  It's clear there is a strong angle <br>dependence on the cross section.  He also looked at the ratio of the cross sections, and saw a strong dependence on Q<sup>2</sup>.  Next he <br>will look at the GDH carbon data, once he has access to it.  His slides can be seen [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_112713.pdf here].

*Toby:
**Gave an update on dilution analysis.  He is working on reconstructing the total background from the dilution runs.  When looking at<br>the elastic region, there was some strange structure when the calculated background was subtracted, but the method of scaling the <br>carbon cross section tonitrogen will be less accurate in the elastic region.  In the quasi-elastic region, he will need to reproduce the elastic <br>radiative tail so that it can be subtracted off.  Moshe has a simulation for the elastic peak and radiative tail for nitrogen, which he will give <br>to Toby.  His slides can be seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/12.11.13.pdf here].

*Pengjia:
**Gave an update on BPM analysis.  Described his improved method for determining the calibration constants, which includes rewriting the <br>diff/sum expression to account for the fluctuation of the pedestal throughout the run period.  By assuming a linear response in the receiver,<br> he uses harp scan data to determine the offset value.  He also uses the absolute beam position found from harp scans to examine the <br>nonlinearity of the diff/sum method.  The biggest issue is with the fluctuating pedestal, as it seems to change even within the same gain <br>setting.  Details on his method can be seen in Pengjia's slides,[http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/12112013/bpm_status_20131211.pdf here].

*Jie:
**Gave a practice talk for his upcoming talk at the Hall A Collaboration meeting, his slides can be seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/talks/jie_g2p_hall_A_collaboration.pdf here].

==12/04/2013==

Present: Kalyan, JP, Min, Chao, Jie, Jixie, Melissa <br>
By Phone: Karl, Ellie, Toby, Ryan, Pengjia<br>


'''Feature Presentations:'''

*Chao: 
**Gave an update on optics analysis, with target field on.  He started with the "best" septum configuration, 48-48-16 and looked <br>at dp = 0%.    He used the simulation to determine the theta and phi to be used in the fitting routine, and used a point beam, set <br>to the average of the BPM readout.  The reconstructed sieve pattern is decided by the beam position and reconstructed angle.  <br>Improvements from last time include using the direct BPM readout as input for the beam position (since the y-target calibration<br> is not very good), and using the calibrated matrix for the angle reconstruction (as opposed to the straight-through version).  The <br>results look good!  There seems to be a slight offset in all the points, though this can probably be tuned using the data.  Next he <br>will work on calibrating the y-matrix using a similar method using beam position scan data.  His slides can be seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20131204/Chao_WeeklyMeeting_12042013.pdf here].

*Min:
**Gave an update on optics analysis.  She is doing a comparison of target quantities between data and SNAKE.  Previously, she was <br>using the wrong database, correcting this has fixed the offset seen in phi.  For the March 4th run, there is no beam scan data, so <br>she used the y-calibration from March 14th.  There seems to be some contamination in the dp data (from other materials, such as <br>upstream windows), so JP suggested placing cuts on other acceptance variables to minimize this contamination.  Next Min will look <br>at the other dp scan runs.  Her slides can be seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/12042013/12042013.pdf here].


'''General Discussion:'''

*We will have a dry run next week for Jie, who's giving the g2p update at the Hall A meeting.  Chao will make his slides for the Analysis <br>
Workshop available at that time as well.

*Melissa will post a draft of the g2p update for the Hall A report by Friday, so comments can be made before the deadline (Dec. 13th)

*Next year we will have a new meeting time, Thursdays at 10am.

==11/13/2013==

Present: Kalyan, Chao, Jie, Min, JP, Melissa <br>
By Phone: Ellie, Toby, Ryan, Karl, Pengjia, Moshe<br>


'''Feature Presentations:'''

*Toby:
**Gave an update on dilution analysis.  Showed a general expression for the background contributions, written in terms of <br>yields from dilution runs.  Also showed the normalized yields for each background contribution.  The results look reasonable <br>for most kinematic settings, but the elastic setting is questionable.  Specifically, the "missing" quasi-elastic peak.  Toby will <br>check his method, especially the assumption he is making to determine the nitrogen cross section.  He also showed an estimate <br>for the dilution factor of ~0.2-0.3, which agrees with what we expect.  His slides can be seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/11.12.13.pdf here].

*Ryan:
**Working on radiative corrections for nitrogen data from GDH experiment.  Showed nitrogen cross section data for two different <br>beam energies compared with the Dally parameterization.  For GDH kinematics, there is a strong angle dependence on the cross <br>section.  Also showed a detailed diagram of the radiation lengths for the GDH experiment.  Finally, he compared the raw, subtracted, <br>and elastic radiated cross section for GDH data at 6deg.  He did a quick calculation to convert this to 5.66 deg, again showing that the <br>scattering angle plays a large role.  He still needs to get the GDH carbon data from Vince.  His slides can be seen [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_111313.pdf here].

*Jie:
**Gave an updated on the g2p simulation package, specifically the energy loss calculations.  There are three contributions to the <br>energy loss; ionization, internal bremsstrahlung and external bremsstrahlung.  To check the calculations, he compared the energy loss <br>for g2psim to the Geant4 simulation (set up by Jixie) results.  There is a significant discrepancy between the two methods.  Jie will <br>check his method and discuss with Jixie to determine what is causing this difference.  The details of the energy loss calculations can <br>be seen in Jie's slides, [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2013_11_13_simulation/Simulation_update.pdf here].

*Pengjia: 
**Gave an update on the status of the BPM calibrations.  In order to test the method he presented last week, he looked at runs taken later<br> in the run period, which didn't have issues with BPMB.    The method seems to work well for these runs, but JP urged Pengjia to be cautious <br>in making assumptions using this method.  Pengjia will continue to check his method for any potential problems.  His slides can be seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/11132013/bpm_status_20131113.pdf here].


'''General Discussion:'''

*Jie will be giving the g2p update at the Hall A winter collaboration meeting

*Melissa will write the update for the Hall A status report
**Each student should send a 1-2 paragraph summary of their subsystem to Melissa

*Please post all technotes to the wiki!!!

==11/6/2013==

Present: Kalyan, Chao, Jie, Min, JP, Melissa <br>
By Phone: Ellie, Toby, Ryan, Karl, Pengjia<br>

'''Feature Presentations:'''

*Melissa: 
**Gave an update on packing fraction analysis.  She improved her fitting routine to account for the contribution from <br>the quasi-elastic peak (in the case of the dilution runs) and from the hydrogen elastic peak (for the packing fraction runs).  <br>For this setting (2.2 GeV, 2.5T, transverse, target material #7), there seems to be significant difference in yield for each of <br>the four packing fraction runs.  She will look into what is causing these differences.  Her slides can be seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_11_06.pdf here].

*Chao:
**Gave an update on the status of the optics.  There are two different settings for straight-through optics; with and without <br>LHe.  Both are aligned quite well, and the straight-through optics matrix can be found in the following directory: <br>/g2p/chao/optics/matrix.  This matrix will be used to finish the angle calibration to finish up the straight-through optics <br>analysis. Next up is optics with target field, starting with the "best" septum configuration (2.5T, 2.2GeV).  The method starts <br>with using the straight-through matrix to reconstruct to the target plane, then projecting from the target plane to the sieve slit.  <br>The final step is to do ray tracing from the sieve slit to the target.  After ray tracing the sieve slit pattern has an offset of ~40mrad <br>(~3deg).  Chao's slides can be seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20131106/Chao_WeeklyMeeting_11062013.pdf here].

*Min:
**Gave an update on her results from last week (see [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/10302013/10302013.pdf here]) of comparing target quantities.  By including the energy loss contribution <br> that Jie has added to the simulation package, there is now agreement between the reconstructed delta and the data.  There is <br>still an offset in phi, which Min will work on correcting.  Her slides can be seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/11062013/11062013.pdf here].

*Pengjia:
**Working on BPM calibration for the 3/14 optics runs, as his results do not agree with Chao's fitting results.  He is trying to use <br>the harp scan runs along with BPMA information to determine the calibration for BPMB.  JP voiced concerns over the non-linearity<br> of the harp scan runs.  For next time, Pengjia will use this method for a situation where there were no problems with BPMB to show <br>that it gives a good result for the calibration.  Chao will try to estimate the uncertainty on his result from fitting the data to better<br> compare to Pengjia's result.  His slides can be seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/11062013/bpm_status_20131106.pdf here].

==10/30/2013==

Present: Kalyan, Chao, Jie, Min, Melissa <br>
By Phone: Ellie, Toby, Ryan, Karl, Pengjia<br>

'''Feature Presentations:'''

*Jie: 
**Working on updating the simulation package.  He has included the energy loss due to the various materials in the <br>target (Al, LHe etc.) and from the HRS entrance window.  He showed a comparison of the energy loss at the sieve, with no <br>target field, for the case with and without the energy loss due to multiple scattering.  The results are consistent with each<br> other.  Next he will work on extracting the packing fraction by tuning the rates in his simulation.  His slides can be seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2013_10_30_simulation/packing_fraction.pdf here].

*Ryan:
**Compiled a  list of the information he has on the nitrogen data from the Small Angle GDH experiment, which includes a <br>technote describing the radiation lengths and collisional energy loss and cross sections for several different kinematic settings.  <br>He also showed an example of the cross section data closest to our settings, which is 2.135 GeV at 6 degrees in both 2 and <br>10 MeV bins.  Next he will work on running the radiative corrections code.  His slides can be seen [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_103013.pdf here].

*Pengjia: 
**Working on BPM calibrations for the 3/14 optics run.  For this time period, the "div" (attenuation) was changed from 4 to 2, <br>which had an affect on the BPMB calibration but not BPMA.  The only harp scan data for div=2 with the target field on is from <br>the 3/16 optics run.  To get the center position for BPM B, he will use BPMA and harp data.  To determine the raster size at BPMB, <br>he will used the raster size and BPMA and the raster at the target.  To check the rotation, he will look at two runs; one with only <br>raster x on and one with only raster y on.  The results look promising, however the offset that Pengjia found (1.456 mm) does not <br>match with Chao's result from fitting the data (-3.5mm).  He will check his method to see what could have caused this difference.  <br>His slides can be seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/10302013/bpm_status_20131030.pdf here].

*Min:
**Showed a comparison of target quantities for the SNAKE transport functions and optimized data (using Chao's matrix) for a <br>straight-through run.  The beam position used was determined from Chao's fitting of the data, but is also consistent with Pengjia's <br>results.  The comparison for theta seems ok, though the mean of the peaks is off in some cases.  She will check to make sure there <br>isn't a negative sign missing between the data and SNAKE variables.  There was a considerable shift in the delta distribution, which <br>may be due to energy loss, since the SNAKE model currently does not include this.  There was also a shift in the phi distribution; <br> after manually shifting the data by 0.004 rad the results seem to agree.  Min will check for possible inconsistencies of variable <br>definitions that could have caused this shift.  Next she will update her results using the latest optics matrix and will compare with <br>other delta scan runs.  Her slides <br>can be seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/10302013/10302013.pdf here].

'''General Discussion:'''

*Chao: 
**g2p simulation is currently being compiled by several different people.  Once it is ready it will be distributed for everyone's use.  <br>He will give more details about this next week.

==10/16/2013==

Present: Kalyan, JP, Jixie, Jie, Min, Chao, Melissa <br>
By Phone: Karl, Ellie, Toby, Ryan, Pengjia, Moshe<br>

'''Feature Presentations:'''

*Pengjia: 
**Working on calibrations for BPMB for the optics run on 3/14.  He is using BPMA and harp scan data (from 3/16) to <br> get the center position at BPMB.  To deterime the raster size, he is using the raster size at BPMA and the size <br>calulated from the carbon hole.  Currently, he is trying to find a method to fit two circles in a 2D histogram; one <br>for the hole size, and one for the raster size.  He still needs to figure out how a deviation from the circular fit <br>will relate to the uncertainty.  His slides can be seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/10162013/bpm_status_20131016.pdf here].

*Melissa:
**Showed a method to get the packing fraction using dilution runs.  The estimate for the packing fraction found using <br> this method seems very low, even with the approximations made.  The most likely reason is that her expression for the <br>yield does not account for the atomic mass of the target.  She will update her calculations to include this and compare<br> the results with other energy settings.  Her slides can be seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_10_16.pdf here].

*Melissa & Toby:
**Showed a comparison of their asymmetry results for all energy settings.  While the results overall look good, there <br>are some discrepancies.  They will chose one kinematic setting to focus on and determine the cause for these differences.  <br>The slides can be seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Asym/AsymCompare.pdf here].

*Moshe:
**Showed his progress on comparing cross section models to Vince's data.  The data does not seem to match well with the<br> QFS or Bosted model, but these models may not be valid in this kinematic region.  He will continue to use a cross section <br>model in his simulation until the radiative corrections for the nitrogen data are completed.
**Also showed his method for extracting the packing fraction.  To avoid quasi-elastic contributions, he does a simple <br>background subtraction by subtracting a helium dilution run from a production run.  By taking the ratio of the heavy elements <br>peak and the hydrogen peak, he can extract the packing fraction.  His preliminary results look good, with a packing fraction <br>of 0.46 (0.43) from the lhrs (rhrs) data.  This result will be used as an input for the GEp event Generator, which will then <br>provide a better estimation for the packing fraction through further iterations.  His slides can be seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/moshe/MFoct1613.pdf here].

==10/9/2013==

Present: Kalyan, JP, Jixie, Jie, Min, Melissa <br>
By Phone: Karl, Ellie, Toby, Ryan, Pengjia<br>

'''Feature Presentations:'''

*Toby: 
**Described his method for determining the dilution factor.  He expressed the number of scattered electrons in <br>terms of the background contributions, specifically in terms of known quantities which can be determined from <br>our dilution runs.  There may be small contributions from other materials (target cup plastic, target nose, etc.),<br>which Toby can include as corrections later on.   JP pointed out that, while this method works well in the DIS region,<br>it may be less valid in the resonance region; we will need to use Vince's nitrogen data to determine the nitrogen/carbon <br>cross section ratio.  Toby's slides can be seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/10.09.13.pdf here].

*Ryan:
**Looked at yields for 2.2 GeV, 2.5T, transverse setting.  He looked at the first few momentum settings, with the <br>goal of correcting for the "gap" that appears between momentum settings.  He started by making narrower focal plane <br>cuts to cut out any "junk" on the edge of the acceptance.  The result was that the gaps between momentum settings <br>actually got larger, and that making tighter focal plane cuts reduced the "strength" of the elastic peak.  He will try to adjust <br>the cuts (wider y-cut, narrower theta cut) to see if this improves the result.  There seems to be good agreement for the yields<br> between runs in the same momentum setting.  His slides can be seen [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_100813.pdf here].

*Pengjia:
**Working on BPM calibrations.  Showed the change in pedestal for each channel of the BPM throughout the run period.  Most <br>of the "jumpy" periods seem to occur when settings were changed.  Also showed the results of calibrating BPMB based on BPMA <br>and harp scan information.  The resulting raster pattern does not have a uniform distribution of events; there seems to be a hot-spot <br>near the center.  Pengjia says this is a result of the happex DAQ, as is the hole in the center of the raster pattern.  He will reconstruct <br>the same plot from HRS results to see if it looks the same.  Also, he will show the raster pattern from BPMA to see if the distribution is<br> the same.  His slides can be seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/10092013/bpm_status_20131009.pdf here].

*Jie
**Working on determination of t0 for VDCs.  Last time he showed two different methods for determining t0.  The first used the<br> maximum slope of the VDC time distribution as the t0 offset.  The second method used the maximum slope to extrapolate to <br>zero on the TDC channel axis, using the intercept as the t0 offset.   This time, Jie compared the two methods and looked at the<br> effect on the tracking variables.  The effect is small, with RMS ~10e-5.  He is also working on updating the multi-track efficiency <br>code using tight acceptance cuts.  Next he will work on the simulation package.  His slides can be seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2013_10_07_t0_final/VDC_10_07_2013.pdf here].

==10/2/2013==

Present: Kalyan, JP, Jixie, Jie, Min, Melissa <br>
By Phone: Alex, Ellie, Karl, Toby, Ryan, Pengjia<br>

'''Feature Presentations:'''

*Melissa: 
**Looking at elastic yields for dilution runs, specifically the 2.2 GeV 5T longitudinal setting.  The results so far <br>don't make sense, but it seems there is a problem with the definition of the yield.  Due to the way the livetime <br>information was calculated, the prescale must also be accounted for in the yield formula.  Her slides can be <br> seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_10_02.pdf here].

*Min
**Gave an update on optics analysis.  She determined new transport functions using trajectories from the latest <br>SNAKE simulation.  She incorporated the new transport functions into the g2p simulation and compared the thrown <br>and reconstructed results.  Overall the results look good, with some discrepancies that she will look in to.  Also, she <br>needs to check if the code accounts for energy loss.  Next she will compare variables at the target plane for runs with <br>out the sieve.  Her slides can be seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/10022013/10022013.pdf here].

*Pengjia
**Working on BPM calibrations.  Jixie talked to the survey group and provided Pengjia with updated survey information, <br> but there is no uncertainty given for the angle.  Pengjia showed a table of the resolution and uncertainty for the entire <br>run period.  The resolution at the target seems suspect; he will check his calculation and provide the formula he used next <br> time.  He is still working on calibrating BPMB using BPMA and the harp scan data for the "bad runs" listed in the table.  His <br>slides can be seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/10022013/bpm_status_20131002.pdf here].

==9/25/2013==

Present: Kalyan, JP, Jie, Jixie, Min, Melissa <br>
By Phone: Chao, Ellie, Karl, Toby, Ryan, Pengjia<br>

'''Feature Presentations:'''

*Jie: 
**Showed a summary of the t0 calibration for the VDCs.  He used two different methods to find t0.  The first <br>method uses the point where the slope is steepest as t0.  The second method looks for the point where the slope <br>is steepest, then extrapolates to the TDC channel axis to find t0.  The remaining question about both methods is <br>how to deal with events that have t < 0.  Jie will provide more details of how these events are dealt with.  His slides <br>can be seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2013_09_24_multi_track_notes/VDC_summary.pdf here].
**Also wrote up a technote for the multitrack analysis, which can be found [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2013_09_24_multi_track_notes/vdc_eff.pdf here].  Feedback would be appreciated.


'''General Discussion:'''

*Pengjia:
**Still working on BPM calibrations, will hopefully be done in the next couple of weeks.  He will also provide a <br>global picture to describe quality of BPM information throughout the run period.

*Ryan:
**Updated the trigger efficiencies to use actual PID cuts (previous cuts were estimated), and results are in the mysql<br> database.
**Got nitrogen/carbon data from Vince and will start looking at radiative corrections.  The carbon data may not be <br>reliable due to ice build-up on septum during the run period.

==9/18/2013==

Present: Kalyan, JP, Jie, Jixie, Melissa <br>
By Phone: Ellie, Toby, Ryan, Chao, Pengjia, Karl<br>

'''General Discussion:'''

*Pengjia: Discussion on BPM calibrations, specifically the period in March when the calibration for BPMB is bad.  <br>For the new calibration, Pengjia is using harp scan data to determine the position, and is determining the <br>radius by using either the "carbon hole" target or the BPMA raster size.  JP says he needs to use both pieces of <br>information to determine the size.  Pengjia needs more information from the survey group, JP/Jixie will talk to <br>them to get more details.


*Toby: Working on setting up replay on new ifarm machines.  Chao has already setup Root/Analyzer.  There are <br>still some problems with replay, which will hopefully be fixed by the end of the week.



*Analysis Tasks:
**Optics and BPM calibrations are still ongoing (Min, Chao and Pengjia)
**Next step is looking at elastic runs and determining the packing fraction and dilution factor.  An important <br>contribution to this will be the nitrogen/carbon data from the small angle GDH experiment (from Vince).
***Ryan will work on radiative corrections for GDH nitrogen data
***Toby will work on determining the dilution factor
***Melissa will look at elastic data to understand spectrum, and will do a cross check of PbPt (once dilution factor is ready)
***Jie will work on setting up simulation program to get packing fraction
**For reference, the analysis flowchart can be seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/kalyan/g2p_analysis_flow_feb2013.pdf here]

==9/11/2013==

Present: Kalyan, Chao, JP, Min, Melissa <br>
By Phone: Alex, Moshe, Pengjia, Ellie, Toby, Ryan<br>


'''Feature presentations:'''
*Pengjia:  
**Gave an update on the status of BPM calibrations.  At one point during the run period, the "div" <br>(attenuation) was changed from 4 to 2, which did not affect the calibration for BPMA but seems to have had <br>a large affect on BPMB.  To solve this problem, Pengjia is using a "brute force" calibration, where he finds a <br>reliable beam position from BPMA, then uses the carbon hole to determine the target center.  From there he <br>can adjust the calibration coefficients to optimize the calibration for BPMB.  JP suggested using a different <br>method to determine the center of the hole, as using the carbon is not a reliable method since the target will <br>move slightly during cool down etc.  His slides can be seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/09112013/bpm_status_20130910.ppt here].

*Toby: 
**Showed raw and physics asymmetry results as a comparison to Melissa's results.  However, there are still <br>some problems with the pass 2 replay, specifically the insertion of the helicity into the rootfiles, so these<br> results do not contain the full statistics.  His slides can be seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/09.11.13.pdf here].
**Also, the computer center will be upgrading to CentOS 6.2 by the end of the month, so Toby will work <br> with Jixie and Chao to rebuild all the g2p software on the new machines.

*Moshe:
**Gave an update on the status of the GEp event generator.  He is using models for elastic hydrogen, helium-4 and<br> nitrogen-14 cross sections, and is using P. Bosted's model for non-elastic cross sections.  JP suggested looking at <br>data (from Vince) for nitrogen, as the Bosted model will not be enough and the quasi-elastic nitrogen contribution is <br>quite large.  He is also working on calculating the energy loss using a Geant4 simulation, but first he will need to <br>determine a value for the packing fraction (for each target material) by using HRSMC.  His slides can be seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/moshe/meetingSep11_MF.pdf here]

==9/4/2013==

Present: Kalyan, Chao, JP, Jixie, Min, Jie <br>
By Phone: Ellie, Toby, Ryan, Karl <br>


'''Feature presentations:'''
*Chao:
**From last meeting we start to doubt the beam position. So Chao modified the program optimizor<br> such that it can also calculate the beam position at the end of the fit.  The detail is that chi^2 <br>is now defined as Chi^2=dX^2+dY^2, where dX and dY are the distance of projected-back-position to <br>beam position, and this projected-back-position is based on surveyed sieve hole position and reconstructed theta | phi angles. <br>The program is ready to run and the result shows that the beam position given by BPM on March 4 is OK while on March 14 is not correct. <br>The uncertainty of the beam position fitted by this program <br>is about 1.5 mm.<br>
**His talk can be found [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20130904/Chao_WeeklyMeeting_09042013.pdf here].

*Min:
**Gave an update on SNAKE tuning. The focal plane variable of March 4 can match the real data with uncertainty <br>when select only the center row.  But can not match well with March 14 data. The septum current ratio optimized by <br>matching focal plane of these data set agrees with Jixie's Geant4 prediction. <br>
**Mannually shift the BPM horizontal position of March 14 optics runs, she found that the focal plane variables <br>can be matched within unsertainty when shifted from 4.5 mm to -3 mm or -4 mm.  This indicates that the BPM position <br>of March 14 runs are not reliable.  
**Started to adjust aperture on SNAKE. JP suggested also using reconstruction matrix to do reconstruction and then <br> match the target plane variables.
**Will tune quartroples later.

*Jie:
**Just back from China. Will work on writing the multi-tracks-analysis-note.

==8/28/2013==

Present: Kalyan, Chao, JP, Jixie, Min, Melissa <br>
By Phone: Ellie, Toby, Ryan, Karl, Pengjia <br>



'''Feature presentations:'''
*Ryan
**Looked at livetime asymmetries for all production runs over each momentum/energy setting and determined the mean <br>value, error and standard deviation for each resulting histogram.  The livetime correction to the yield is done on a run-by-run <br>basis, but this method will allow Ryan to look for any overall systematic shifts in the livetime.  JP suggested correcting the <br>livetime asymmetry within each momentum setting with the "expected value" so that all runs can be combined to increase the <br>total statistics.  Also, each run should be weighted by statistics to make the standard deviation a meaningful representation of <br>the uncertainty.  His slides can be seen [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_082813.pdf here].

*Pengjia
**Gave an update on the status of the BPM calibration.  Showed the uncertainties provided by the survey group, which gives an <br> uncertainty at the BPM of 0.25mm.  He needs to contact the survey group to better understand the values provided.  
**Also showed a timeline of calibration settings for early in the run period (March).  Looking first at BPMA, it seems that the <br>calibration is fairly stable over this period.  However, the calibration for BPMB is not very stable.  It seems that using different "div" <br>settings (2 or 4) caused the BPMB settings to change but did not affect BPMA.  JP suggested looking at runs immediately after the <br>calibration is done to see when the calibration for BPMB goes bad.  Pengjia's slides can be seen   [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/08282013/bpm_status_20130828.ppt here].



----

==8/21/2013==

Present: Kalyan, Chao, JP, Jixie, Min, Melissa <br>
By Phone: Ellie, Toby, Ryan, Pengjia, Alex <br>



'''Feature presentations:'''
*Melissa
**Updated previous asymmetry results to include charge/livetime/prescale normalization for all energy settings.  Also <br>showed the corresponding physics asymmetries.  The 1.1 and 1.7 GeV settings need some work, as the scaling from raw <br>to physics asymmetries doesn't quite make sense.  Also need to look at asymmetries run by run to identify any possible bad <br>runs.  Her slides can be seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Asym/Asym_08_21.pdf here].  

*Chao
**Last time he found an offset between two sets of straight-thru data and is working on determining the reason for this <br>offset.  He first tried using only first order matrix elements for the optimization, but the resulting sieve pattern was not <br>aligned very well.  Next he tried including second order matrix elements in the optimization, using the data from a run with<br> liquid helium.  Using this database to look at the run without liquid helium revealed a horizontal offset of 7.3mm.  A possible <br>reason for this offset is that the BPM information is not quite correct.  To check this he looked at simulations for two different<br> beam positions.  The results looked suggested only a -0.3mm horizontal offset.  Finally, he compared the focal plane plots for <br>settings with and without liquid helium.  The bpm tells us there should be a ~7mm offset (~8mrad) difference between the <br>settings, but the data shows only ~2mrad difference.  Chao will work with Pengjia to try to determine if there is a problem with <br>the bpm information.  His slides can be seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20130821/Chao_WeeklyMeeting_08212013.pdf here].

*Min
**Merged the db_run.dat and db_run.dat files for left and right HRS into one file to fix problems with replay on batch farm.
**Working on tuning the SNAKE parameters.  She found the best results by adjusting the position of the septum and HRS along <br>the beam direction.  Looking at the focal plane distribution for SNAKE and the data, there is a point where the SNAKE model "turns" <br>away from the data.  Moving the HRS from its original position (1.96mm) to 0 does not seem to help, but moving the HRS and <br>septum both in the negative-y direction seems to correct for this "turn".  Looking at a run with a large beam offset, there seems to be <br> a much larger difference between the data and SNAKE.  Further, the plot of x vs y doesn't seem to match at all.   It's possible that the <br>issue with bpm information that Chao found is causing similar problems for Min; she will try fixing the magnet positions and adjusting <br>the beam position to see how this effects her results.  Her slides can be seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/08212013/082113_min.pdf here].





----

==8/14/2013==

Present: Kalyan, JP, Chao, Min, Melissa <br>
By Phone: Ellie, Toby, Ryan, Karl, Pengjia, Alex, Guy <br>



'''Feature presentations:'''
*Pengjia
**Showed an update on the status of BPM calibrations. He is currently using a method where he looks at the linear <br>portion of the BPM current vs. signal, and extrapolates the fit to determine and offest.  This offset is used instead <br>of the pedestal value.  JP is concerned about using this method - he and Pengjia will discuss it more offline.  
**Also mentioned the makeup of the uncertainty for BPM calibrations.  It will come from the BPM hardware resolution <br>(plus addition noise from radiation), uncertainty in the survey, and possibly a third contributer.  The Beampackage is <br> ready to calibrate bpms and rasters for all run periods, with the exception of the fast raster which still has some issues. <br> His slides can be found [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/08142013/bpm_status_20130814.pdf here]

*Toby
**Presented raw asymmetries from pass 2.  The results looking promising but still need to be corrected for charge, <br> livetime and prescale, and should use focal plane variables for acceptance cuts instead of "gold" variables.
**Also, there are still a few issues with the replay for pass 2 that need to be corrected.  His slides can be seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/08.14.13.pdf here]. 

*Ryan
**Showed the results of livetime asymmetry analysis.  He cross checked his results using scalar totals from both the <br>TTree and hel_ring tree, which also turned out to be a good check of the helicity decoder.  In general, he found most <br> runs had a livetime asymmetry of less than 200 ppm.  He will check to see if the distribution of his results is gaussian.  <br>The results are also in the mysql database.  His slides can be seen [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_081413.pdf here].


----

==8/7/2013==

Present: Kalyan, Jixie, Chao, Alex, JP, Min, Melissa <br>
By Phone: Ellie, Toby, Ryan, Karl, Pengjia <br>

'''General Discussion:'''
*Karl posted a couple of new papers to the wiki, they can be found [http://prd.aps.org/abstract/PRD/v87/i5/e054032 here] and [http://prd.aps.org/abstract/PRD/v85/i1/e016012 here].


'''Feature presentations:'''
*Melissa
**Showed raw asymmetry results for 2.2 GeV, 2.5T setting.  JP suggested only using focal plane variables (not <br>reconstructed variables) for acceptance cuts until optics with target field is completed.  Also, the prescale value <br> needs to be included to account for total statistics.  Once the issues with the second farm pass are resolved, she <br>will include the normalization for charge/livetime and complete the analysis for all energy settings.  Her slides can <br>be seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Asym/Asym_08_07.pdf here].

*Chao
**Showed an update on first order matrix calibration for the straight-thru conditions.  Min did a study where there <br>was helium in the target nose, now Chao is doing a similar study but using runs where there was helium in the target <br>nose.  Using the most updated BPM information, there is still a ~1.5mm offset in the horizontal direction.  He is able<br> to clean up the data by cutting on focal plane and y-target, then makes a dp cut to distinguish between helium and <br>carbon peaks.  Comparing his results for the first order matrix to the results without helium, the matrix changes quite <br>a bit.  He will try to figure out what is causing this change and will compare the results to the SNAKE model.  His slides <br>can be found [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20130807/Chao_WeeklyMeeting_08072013.pdf here].

*Min
**Working on matching SNAKE model to the data.  Showed the results (for two sieve holes) of moving the septum and/or <br>HRS magnets by 1-2mm.  There seemed to be some improvement, but she will continue to study this.  She will also look <br>at the rest of the sieve holes to see the distribution/acceptance.  Her slides can be found [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/08072013/080713_snake.pdf here].




----

==7/31/2013==

Present: Vince, Kalyan, Chao, Min, Jixie, Melissa <br>
By Phone: Ellie, Toby, Ryan, Pengjia, Alex <br>

'''Feature presentations:'''
*Pengjia
**Gave an update on the status of the BPMS.  Showed plots of current vs raw BPM ADC values for several different <br>beam positions and saw that the distribution is linear above 30nA.  Using the offset of the fit to the current, <br>he can determine the pedestal for each channel.  Overall, the results look much better using this method, <br>although BPMB may still have some issues.  Also showed a plot of raw current vs entry number.  The spread in <br>position looks better then before using the new values for the pedestals.  Next he will try to improve his <br>method to minimize current dependence and will try to use a non-linear fitting of calibration data.  His <br>presentation can be found [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07312013/bpm_status_20130731.pdf here] 

*Toby
**Working on pass-2 of farm replay.  There were some issues using the batch farm, but they seem to be fixed now.  <br> Rootfiles should be ready soon!

*Ryan
**Was delayed by problems with helicity decoder, but should be able to finish helicity dependent deadtime analysis soon.


----

==7/24/2013==

Present: Vince, Kalyan, Chao, Min, Jixie, Melissa <br>
By Phone: Moshe, Pengjia, Ellie, Toby, Ryan, Guy <br>

'''Feature presentations:'''

*Chao:
**Gave an update on simulations using the straight through optics conditions.   He showed results comparing <br> the reconstructed and thrown variables for 3 cases. First, assuming an uncertainty in bpmA/bpmB of 0.2/0.4 mm.  <br>Second, assuming no resolution in the bpms .  And third, using only bpmA.  From this he concluded the BPM <br>resolution will contribute 2e-4 to the delta reconstruction.  A question was raised as to why the phi distribution was  <br>so wide.  Chao will check this for next time.
**Also updated the simulation package.  The most recent version of the event generator uses a “random walk” <br>algorithm to generate particles following the cross section distribution.  The simulation code is available for use, <br>and Chao will work on producing some documentation.
**Next up is working on optimizing the optics matrix for March 4th data to help Min, since the simulation package <br>will need input from her SNAKE model.  His presentation can be found [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20130724/Chao_WeeklyMeeting_07242013.pdf here].

*Min
**Gave an update on her SNAKE model.  Using the most updated beam package and looked at the distributions of <br>the current, bpmA, bpmB and target variables versus entry for run 3185 (for both x and y).  The distribution of the <br>target variables seems to follow the bpmB distribution.  She selected a region of events in this run to remove <br>oscillations.  Looking at the results for the uncertainty from the first order matrix, the uncertainty seems to be smaller <br>then before with delta-y = 1.90mm and dela-phi = 0.68mrad.  However, looking at the current results for tuning the <br>septum field, the comparison between SNAKE at the data is not much better. 
**Next she will try moving the location of the quads by 1-2mm and comparing the trajectories of runs 2725 and 3185. <br>Her presentation can be found [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/07242013/072413_snake.pdf here].

----

==7/17/2013==

Present: Vince, Chao, Min, Jixie, Kalyan <br>
By Phone: Ellie, Alex, Toby, Moshe, Pengjia, Karl <br>

'''Feature presentations:'''

*Pengjia:
**Present the pedestal as a function of time for the whole data set. The pedestal were <br> drifting along time. They were not stable at all. Currently Pengjia subtracts only the averaged pedestal <br> of a period of time to reconstruct beam position for that period. He will need to do the subtraction run by run. <br> 
**Also presented are the BPM calibration against Harp position for 100, 75 and 50 nA. It seems that the <br> calibration for 50 nA need to be redone. He also shown that the calibration constant is sensertive to <br>  beam current. Whenever the beam tripped and then the beam position is not stable during the current was <br> ramping up.
**See detail [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07172013/bpm_status_20130717.pdf here].

*Moshe:
**Working on an event generator for simulation.  Right now he is working on the energy loss caculation <br> using both EStar and Geant4. He mentioned that the energy loss result from EStar <br> does not agree with that from Geant4. <br> 
**He is also trying to get cross section models for helium-4 and nitrogen-14. He has QFS model <br> in hand but this model is known to be poor. Vince agreed to provided him with some N-14 <br> data and Moshe will try to compare P.Bosted's model with Vince's data. Then decide which model to use.
**See his presentation [http://hallaweb.jlab.org/experiment/g2p/collaborators/moshe/meeting_Jul1713.pdf here].

----

==7/10/2013==

Present: Vince, Chao, Min, Jixie, Melissa <br>
By Phone: Ellie, Ryan, Toby, Moshe, Pengjia, Karl <br>

'''Feature presentations:'''
*Chao
**Gave an update and summary of the helicity decoder  There were a couple of bugs that needed to be fixed, <br>including the one bit delay.  Also, the ring buffer creates a set of unused, extra events at the beginning of each <br>run, which will now be marked as an error.  Finally, there was an alignment issue when inserting helicity information <br>back into the rootfile.  These issues should all be fixed now.  When using the decoder, the variable that should be <br>used to obtain the correct helicity of an event is "hel_act", and all events with hel_error /= 0 should be cut out.
**Also working on improving the decoder to deal with beam trip cuts.  The cut should be made in units of helicity <br>patterns, so time information (from the fast clock) will be added to help make these cuts.  His slides can be found [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20130710/Chao_WeeklyMeeting_07102013.pdf here].

*Melissa
**Gave a summary of her method to determine raw asymmetries including the applied cuts and method for extracting <br> the asymmetry.  However, the issue with the helicity decoder described in Chao's talk means that the results shown are <br>not reliable.  Concern was expressed over the error bars shown, she will carefully check this when she re-does the <br>analysis with the correct helicity information.  Her slides can be seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Asym/Asym_07_10.pdf here].

*Min
**Updated the LHRS optics calibration by including beam trip cuts and using the latest bpm information from Pengjia. <br> The results seem better!  Cuts still need to be applied for when the beam moves.  Since BPMB is not always stable, she <br> thought about just using BPMA to calculate the beam position at the target.  Vince suggested that by correcting for the <br>beam movement the poor resolution in BPM B might be less significant and Min could still get reasonable results.  Her <br>slides can be found [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/071013/07102013_LHRS.pdf here].




----

==7/3/2013==

Present: Kalyan, Chao, Min, Melissa <br>
By Phone: Ellie, Ryan, Toby, Pengjia, Alex <br>

'''Feature presentations:'''
*Ryan
**Updated the MySQL database to include Jie's results from multi-track analysis and Toby's results from target <br>polarization analysis.  This information is also now included in the ROOT library.  Also fixed several bugs that caused <br>missing information for some runs in the database.  He is also working on helicity dependent deadtime analysis.  <br>His slides can be seen [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_070313.pdf here].

*Pengjia
**Gave an update on BPM analysis.  He compared two techniques to reduce noise in the pedestal; applying a filter <br>and taking the average of every two seconds of data.  The two methods seem to give similar results.  For next time <br>he will look at how the change in current affects the position, and how using a 2Hz filter affects the mean value of <br>the BPM.  His slides can be seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/07032013/bpm_noise_wfilter_20130703.pdf here].

*Toby
**Finished writing a technote for the target polarization analysis and will be looking for feedback soon.  He will also <br>start preparing for a second round of farm replay, since no event-type information exists in the rootfiles currently.


----

==6/25/2013==

Present: Karl, JP, Chao, Kalyan, Min, Melissa <br>
By-Phone: Ryan, Toby, Ellie, Pengjia, Alex, Moshe <br>

'''General Discussion:'''
*Ryan will submit an abstract for a general g2p talk for the DNP meeting this fall.


'''Feature presentations:'''
*Chao
**Gave an update on optics simulation package.  He showed the results of comparing the reconstructed and thrown <br>variables from simulation to see if he could reproduce the central value of delta, theta and phi.  He determines the <br>average for each variable by taking the average of each point and weighting by the cross section.  Currently, his <br>reconstruction stops at the target plane with z=0, which assumes that the target is symmetric along the z-direction.  <br>He needs to find a careful way to correct for this.  His presentation can be found [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20130626/Chao_WeeklyMeeting_06262013.pdf here]

*Min
**Gave an update of LHRS optics calibration.  She worked with Pengjia to get the bpm package with filter working <br>for ifarm replay (only LHRS for now, RHRS will be working soon).  She used the updated bpm information to update <br>her results for straight-thru optics.  She found that the results for theta were larger by a factor of ~3.  She will try to <br>figure out if this is a result of the bpm filter or something else.  She will also update her results to include cuts for <br>beam trips and beam moves.  Her presentation can be found [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/06262013/062613_LHRS_revisit.pdf here]

*Melissa
**Gave a followup on beam charge asymmetries.  She updated her results to include beam trip cuts to compare with <br>Pengjia's results.  The effect of adding the beam trip cuts is small (~ >0.05%), and Pengjia and Melissa's results agree <br>within ~1% or less.  She also showed a comparison between results taken from ring buffer data and happex data.  <br>There is a >1% difference between the two systems.  Her slides can be seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/BeamCharge/BeamCharge_06_26.pdf here]



----

==6/19/2013==

Present: Karl, JP, Vince, Jixie, Ellie, Kalyan, Chao, Jie, Min, Melissa <br>
By-Phone: Ryan, Toby, Pengjia, Alex <br>

'''Feature presentations:'''
*Ryan
**Gave a recap of the y-target calibration for the LHRS.  Last time he showed that he got strange results <br> during the optimization, specifically for the (0,0) and (-4,0) settings.  By using a different run for <br>the (-4,0) setting he was able to improve the results.  He then tried maximizing the event number per hole,<br> while still keeping the number of events approximately the same per hole.  This improved the resolution of<br> the results.  He also tried increasing the order of the optimization in the database.  This also improved <br>the resolution, but may not be a reasonable solution since increasing the order can over constrain the matrix. <br>His presentation can be found [https://userweb.jlab.org/~rbziel/Weekly_Meetings/Optics_061913.pdf here]. 

*Pengjia
**Gave an update on BPM analysis.  He is currently rewriting the insert and calibration piece of the <br>beampackage to include the new filter method presented last time.  
**Also working on a beam move check that uses rms detection for fast beam moves, looks at current trip<br> information, and splits events if the beam moves more than 0.3mm.  He is still debugging this.  He <br>also discussed pedestal subtraction for the bpm calibration.  The pedestal shown was quite wide and had <br>multiple peaks.  Pengjia will study this more to determine if this behavior is consistent through all runs,<br> or if this was a specific period when conditions were changing.  His presentation can be found [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/06192013/bpm_status_20130619.pdf here].

*Toby
**Worked with Josh and James to determine that there was in fact a bug in the online code to determine <br>target polarizations.  This means the 2.5T polarization is actually ~50% of what was reported online.  <br>This does not affect the 5T results.
**Showed details for his method of determining the TE points.  He takes the time reported online for the <br>TE as the approximate start time, does a 0th order fit of the points and looks at the chi-squared value. <br>He then adds points until he finds the end point of the TE.  Finally, he adds points at the beginning of <br>the TE to minimize the chi-squared value.  The polarization is then averaged over each run.  He questioned <br>how the polarization decay contributes to the uncertainty for each run, since the poarization is actually <br>decaying over each run.  JP suggested using the average of the decay curve to determine this.  Toby's <br>presentation can be found [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/06.19.13.pdf here].

*Jie
**Has completed the efficiency study for multi-track events.  This information will be in the mysql <br>database soon.
**Also working on data quality checks for optics variables.  He looked at the t0 calibration first. One <br>concern is how "negative time" events are being dealt with.  Jie will check that they aren't being cut out. <br>He also looked at the transport and rotated x,y,theta and phi variables.  Within each kinematic settings, <br>these varibales look stable over all production runs.  Jie will take a closer look the elastic settings next.  <br>His presentation can be found [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2013_06_18_optics_data_quality_check/data_quality_20130618.pdf here].

----

==6/12/2013==

Present: Karl, JP, Vince, Jixie, Chao, Jie, Min, Alexandre, Kalyan, Melissa <br>
By-Phone: Ellie, Toby, Ryan, Moshe, Pengjia <br>

'''Feature presentations:'''
*Chao
**Has fixed the bit-shift problem in the offline helicity decoder.  The next round of farm replay will <br>have correct helicity information.

*Melissa
**Showed a comparison between her and Pengjia's results for beam charge asymmetries.  The results <br>show ~0.5% difference.  It's possible that the beam trip cuts that Pengjia used is the reason for this <br>difference.  Her presentation can be found [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/BeamCharge/BeamCharge_06_12.pdf here].

*Min
**Showed an update of angle and vertex matrix calibration results using previous bpm calibrations.  The results <br>are not better.  She is still working on improving it by applying beam current cuts and beam position cuts.<br>  She will also try using a different run to optimize that has the same conditions but a more stable current <br>She will check that the beam position is also stable during this run.  Her slides can be found [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/06122013/061213_optics.pdf here]


----

==6/5/2013==

Present: Karl, Vince, Kalyan, Chao, Jie, Min, Melissa  <br>
By-Phone: Ellie, Toby, Ryan, Moshe, Guy, Pengjia <br>

'''General discussion:''' <br>
*There will be a practice talk for Min's Hall A Collaboration Meeting talk sometime soon (Friday or Monday?)


'''Feature presentations:'''
*Moshe
**Gave an update on the status of GEp analysis.  He did a first round of analysis without calibrations, <br>to determine a general procedure for analysis.  He showed preliminary results for elastic peak <br>identification, binning optimization, dilution factors and asymmetry extraction.  He is also working <br>on writing a GEp event generator for HRSMC.  His presentation can be found [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Moshe/meeting_June0513_MF-1.pdf here].
**Details of status of GEp analysis can be found in [http://www.phys.huji.ac.il/~SimLiT/.gep/interim_analysis_report.pdf this document], written by Moshe.

*Pengjia
**Working on improving BPM resolution.  He added a low pass, software FIR filter when processing <br>the data, which seems to work very well.  The previous results were 7-8X larger then the results that <br>have been processed with the filter.  He is working on incorporating this into his beampackage code, <br>and will repeat his BPM noise study using the filter.  Will also check if the central value changes at all <br>as a result of the filter.  His presentation can be found [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/06052013/bpm_resolution_improvement_20130605.pdf here].

*Ryan
**Working on the LHRS Y-target calibration.  He optimized 3 runs in the 2.2 GeV (0T, 6deg) setting <br>with different beam positions; (4,0), (0,0), (-4,0).  The results seemed strange, specifically for the (0,0) <br>and (-4,0) settings.  He first tried optimizing each run individually, which gives results that make sense. <br>He then tried optimizing them in pairs, and got reasonable results except for the combination of (0,0)  <br>and (-4,0).  Finally, he tried to check these results using other runs with the same beam positions, but <br>found that during these optics runs, the beam position was never moved back to (0,0).  Vince pointed <br>out that the typical resolution for y-target is ~1mm, so these results may be ok.  Ryan's presentation <br>can be found [https://userweb.jlab.org/~rbziel/Weekly_Meetings/Optics_060513.pdf here].

*Toby
**Showed updated target polarization calibration constants.  He decided to use a 3rd order polynomial <br>to fit the wings of the baseline-subtracted signal.  It's possible that the discrepancy between using a <br>2nd and 3rd order polynomial could result from the signal "bleeding" into the wings.  He described his <br>method for minimizing the reduced chi-squared to find the TE points.  He starts with a set of 15 points <br>where the target is most thermalized, and adds points from the beginning/end of the TE to further reduce <br>the chi-squared.
**He also found that the 2.5T calibration constants found offline are ~50% smaller than what was determined <br>online.  He will work closely with James/Josh to confirm that this really is a problem.  His presentation can <br>be found [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/06.05.13.pdf here].

*Jie
**Showed an updated version of multi-track efficiency analysis.  He determined that his new method of <br>including background cuts is not as reliable as his previous method to determine uncertainty.  By including <br>background cuts, the systematic uncertainty is decreased by about 20%, but it very position dependent, so <br>he suggests staying with his previous results.  His presentation can be found [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2013_06_04_multi_track_eff/Multitrack_20130604.pdf here].