G2p Analysis Minutes

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Minutes of the weekly analysis meetings


Agenda

4/6/2016

Present: JP, Karl, Chao, Ryan, Toby, Jie, Vince, Ellie

Feature Presentations:

  • Toby

Gave an update on the dilution study. He summarized the dilution calculation for the 2.2GeV 5T transverse settings. He also used the dilution result to calculate the asymmetry for this setting. The radiative correction was considered in the calculation. And he concluded that the uncertainty of the calculation is dominated by the packing fraction uncertainty. More details can be seen in his slides here.

  • Ryan

Gave an update on his cross-section analysis of the small angle GDH data. Based on the discussion from previous meetings, he checked the uncertainty of the elastic tail. The calculation includes three different sources: the correction factor representing higher order virtual photon diagrams, bremsstrahlung and multiple photon corrections. For the multiple photon corrections, he mentioned that G.Miller has an alternative multiple photon correction result. He applied the calculation to the saGDH data and it seems that the Miller multiple photon result is better representation of saGDH elastic tails. More details can be seen in his slides here.


3/23/2016

Present: JP, Karl, Chao, Ryan, Toby, Jie, Vince, Ellie

Feature Presentations:

  • Jie

Gave an update on his study of the yield drift problem. He continued his study with dilution runs. The method he used is similar as what he did for the production runs. He made a 6mm radius circle cut and compare the simulation result with the data. There are a few runs which were measured with beam current less than 50nA. After discussion with Pengjia, Jie mentioned that those runs' BPM readout might not be accurate since the BPM is calibrated at 50nA~100nA. He will do further study together with Pengjia to understand this effect. More details can be seen in his slides here.


3/9/2016

Present: JP, Karl, Chao, Ryan, Toby, Jie, Vince, Ellie

Feature Presentations:

  • Toby

Gave an update on the dilution study. He summarized the dilution calculation for the 2.2GeV 5T transverse settings. He also used the dilution result to calculate the asymmetry for this setting. The radiative correction was considered in the calculation. And he concluded that the uncertainty of the calculation is dominated by the packing fraction uncertainty. More details can be seen in his slides here.

  • Ryan

Gave an update on his cross-section analysis of the small angle GDH data. Based on the discussion from previous meetings, he checked the uncertainty of the elastic tail. The calculation includes three different sources: the correction factor representing higher order virtual photon diagrams, bremsstrahlung and multiple photon corrections. For the multiple photon corrections, he mentioned that G.Miller has an alternative multiple photon correction result. He applied the calculation to the saGDH data and it seems that the Miller multiple photon result is better representation of saGDH elastic tails. More details can be seen in his slides here.

  • Jie

Gave an update on his study of the yield drift problem. He and Pengjia fixed the problem in the raster size calculation. He then made some cuts on the raster size to remove the boundary effect. He mentioned some of the runs had hot spot and was able to be corrected by the raster cut. He also summarized the yield spread with raster cuts for all kinematic settings. More details can be seen in his slides here.


2/24/2016

Present: Karl, Chao, Ryan, Toby, Min, Ellie, Jie

Feature Presentations:

  • Toby

Gave an update on the dilution study. He need the scattering angle to calculate the scaling factor between the carbon and nitrogen. However, his study suggests that the scattering angle calculated for the carbon target is larger than the production target. The simulation shows opposite result which is expected to be reasonable from geometries. People suggests Chao to check the scattering angle calculation in the optics package. More details can be seen in his slides here.


2/17/2016

Present: JP, Jixie, Chao, Ryan, Min, Ellie, Jie

Feature Presentations:

  • Chao

Gave an update on the optics study. He finished the matrix recalibration on right arm. The database is updated and is ready to use. The RMS values for angle and momentum calibration are summarized in his presentation. JP and Jixie has some concern about the broken septa seems to cause worse effect on left arm comparing with right arm. They suggested to check this more carefully. More details can be seen in his slides here.

  • Ryan

Gave an update on his cross-section analysis of the small angle GDH data. Based on the discussion from the last week's meeting, he removed the extrapolation part in RADCON and then test the code with some test cross-sections from Pbosted Model. There is no problem in this case. So he compared the Pbosted model with saGDH data at large <math>\nu</math>. He is waiting for the response from Vince about the uncertainty of the saGDH cross-section at large <math>\nu</math>. More details can be seen in his slides here.


2/10/2016

Present: JP, Karl, Alex, Jixie, Toby, Chao, Ryan, Min, Ellie, Vince

Feature Presentations:

  • Ryan

Gave an update on his cross-section analysis of the small angle GDH data. He is dealing the problem that after doing the tail subtraction and radiative correction the cross sections go negative at high <math>\nu</math>. He did a refit of the few low <math>Q^2</math> points using a charge form factor fit. The results still deviated from the PBosted model at high <math>\nu</math>. However, JP and Karl suggests that the code RADCOR code should not give negative cross section result. There might be some problems in the extrapolation part. Karl suggests to check the input data to see if there are constrains at the high <math>\nu</math> region. More details can be seen in his slides here.


2/3/2016

Present: JP, Karl, Alex, Jixie, Toby, Jie, Chao, Ryan, Ellie, Vince

Feature Presentations:

  • Min

Gave an update on her acceptance study. She continued to compare the simulation result with data. Since the optics database is updated with the vertical beam position correction. The result suggests that the delta distribution is improved however the phi distribution still shows large discrepancy. She used this result to calculate the acceptance factor and applied it to the cross-section calculation. The result shows a factor of two difference. JP suggests that the acceptance calculated from the compare between the simulation and the data could still be influenced by the cross-section difference at small scattering angle. More details can be seen in her slides here.

  • Toby

His presentation on 1/12 is reviewed. JP mentioned his concern about the uncertainty propagation. Toby is going to check it again and update his tech note about it.

General Discussion:

  • The replay package is restored on the work disk.
  • Toby will talk to Melissa and take over her packing fraction study.


1/26/2016

Present: Jixie, JP
By Phone: Jie, Chao, Ryan, Ellie

General Discussion:

  • The analysis meeting will be moved back to 10 am Wednesday starting from next week.
  • There is no meeting room available thus everyone will join by bluejeans. The meeting ID is 4828802914.


1/12/2016

Present: Melissa, Jixie
By Phone: Jie, Chao, Ryan, Toby, Ellie

Feature Presentations:

  • Ryan

Gave an update on his cross-section analysis of the small angle GDH data. yield study using simulation. He is working on the problem that after doing the tail subtraction and running the inelastic Radiative Correction code the fully corrected cross sections go negative at high <math>\nu</math>. To solve this, he did a fit on the Nitrogen form factor. During the fitting, two models is considered: the oscillator model and the Fermi Model and the Fermi Model is proved to be better. He will complete the calculation of the elastic tail by using the form factor in a few weeks. More details can be seen in his slides here.

  • Toby

Gave an review on the polarization uncertainty estimation. He claimed that the reason of the small uncertainties for the target polarization is because we took large amount of TE for each material. Thus the uncertainty of the calibration constant is reduced by average. Jixie suggests that the error propagation still need to be carefully checked. More details can be seen in his slides here

General Discussion:

  • Chao updated his optics technical note.
  • There is no meeting next week due to the Hall A collaboration meeting.



Jul-Dec 2015

Minutes_Jul2015_to_Dec2015


Jan-Jun 2015

Minutes_Jan2015_to_June2015


Jul-Dec 2014

Minutes_July2014_to_Dec2014


Jan-Jun 2014

Minutes_Jan2014_to_June2014


Jun-Dec 2013

Minutes_June2013_to_Dec2013


Jan-May 2013

Minutes_Jan2013_to_May2013


April-Dec 2012

Minutes_Apr2012_to_Dec2012


Jan-Mar 2012

Minutes_Jan2012_to_Mar2012


Jul-Dec 2011

Minutes_July2011_to_Dec_2011


Jan-Jun 2011

Minutes_Jan2011_to_June_2011