Difference between revisions of "G2p Analysis Minutes"

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	[https://hallaweb.jlab.org/wiki/index.php/G2p_Weekly_Analysis Agenda]		[https://hallaweb.jlab.org/wiki/index.php/G2p_Weekly_Analysis Agenda]
−	==7/8/2015==
−	Present: JP, Min, Chao, Melissa <br>	+	==07/29/2021==
−	By Phone: Toby, Vince <br>	+	Present: JP, David
−	'''Feature Presentations:'''	+	*David showed a zoomed in plot of the Q^6 Delta_LT scaling agreed upon last week, and JP and David both agreed that this made the high point look unnecessarily bad. David agreed to make a similar version of the Q^4 plot to decide between next week, and include the Q^6 plot in the current paper draft.
		+	*David mentioned that he found Chao's internal presentation of an elastic study which yielded a contribution to the acceptance systematic of 4%. JP commented this was likely to be the dominating systematic for the acceptance and suggested that David use this to obtain a back of the napkin calculation of the XS systematic. JP also suggested that this systematic could be representative of our overall uncertainty in the 1.15 scaling to match the g2p data to the Bosted model, and that we could potentially quote this number to anyone who raises issue with the scaling factor.
		+	*There was a brief discussion of the Drechsel paper JP found, he suggested Karl would probably have access and that the discussion in that paper would likely feed what we should say about d2 in our paper.
		+	*David mentioned that he has been working this week on making a draft of the paper with Karl's comments from last week and JP's comments from this week, and would try to finish in the next day or two to send to the Spokespeople.
		+	*David will be traveling next week but available for a meeting, JP suggested if the draft was sent out this week it would be a good time for a short meeting for Karl, JP, and any others to share their current thoughts and comments on that iteration of the draft.
		+
		+	==07/22/2021==
		+	Present: Alexandre, JP, Karl, David
		+
		+	*David showed a number of slides showing delta_LT multiplied by various powers of Q2.  We commented that Drecschel shows Q6/M2 delta_LT in his paper.  Also the 2004 E94010 polarizabilities showed the same quantitty.  So there is precedent for this.  David will produce a zoomed version of the plot.  He also showed delta_LT/gamma_0, although he has low confidence in the present error bars.  He will revisit and he and Karl will try to add RSS data, Maid and pdfs to see if the transition to the predicted scaling at very large Q2 is at all visible at this very low Q2.
		+	*JP Asked David to look at threshold again, and to try to dig out Chao's evaluation of the acceptance uncertainty from the elog and old wiki presentations.
		+	*Alexandre reminded that there is a lot of good old information in the elog : https://hallaweb.jlab.org/dvcslog/g2p/
		+	*We switched the weekly meeting time to 10:30am on Thursdays.
		+	*Karl will be on travel next week, but expects to be available for the weekly meeting.
		+
		+
		+
		+
		+	==05/01/2019==
		+	Present: JP, Karl, David
		+	'''Feature Presentations :
		+
		+	*David
		+	Showed a number of slides building up the 2.5T 2.2GeV dilution one step at a time to try and analyze any outstanding issues. These plots showed severe edge effects from the momentum settings on all run types. J.P. and Karl suggested fixing this by doing a fit to one of the yield, and then using an offending momentum setting to find a dp correction to the fit and apply it everywhere. The plots also showed several momentum settings where the centroid appeared to be shifted, David promised to do some detective work to try and figure out why.
		+
		+
		+	'''Verbal Updates:
		+
		+	None
		+
		+	==12/06/2018==
		+	Present: Karl, Chao, David
		+	'''Feature Presentations :
		+	None.
		+	'''Verbal Updates:
		+
		+	*David
		+	Discussed a final issue with Chao leading to simulated peaks being smeared too wide, because of a smearing parameter in the input file being too big. Said he should have final 5T Longitudinal packing fractions next week, and is prepared to have final 2.5T 2.2GeV packing fractions once Snake Model is complete. Also showed a plot of Gamma 2 indicating that the cost to using just the Material 8 data for the 2.2GeV 2.5T would be costly, more than doubling the total error bar and changing the central value slightly, highlighting the need to use one of the other methods discussed to complete the analysis.
		+
		+	*Chao
		+	Chao said that he will be needing to leave the field and seek a job in industry starting in January, but said he would finish updating the Snake model before he goes so that the packing fraction analysis can be completed with the new method.
		+
		+	==10/04/2018==
		+	Present: J.P., Karl, Chao, David
		+	'''Feature Presentations :
		+
		+	*David
		+	Showed several slides on the current status of the 2.5T packing fraction. With several issues fixed, the carbon peak shows good agreement with the helium peak subtracted by using a helium simulated elastic peak and subtracting it scaled by the appropriate packing fraction. For the production data, this process was repeated with an iterative process for the packing fraction of helium, showing no sensitivity to initial guess and converging on relatively reasonable packing fraction results. J.P. and Karl suggested that the fit between the simulation and the data is not perfect, it may be a reasonable enough comparison to function. However, for Material 7, the elastic yield is much sharper than for Material 8, and while the latter matches the shape of the simulation well, the former looks very different. Karl suggested to look into how the materials compare to the simulation for other settings, and J.P. noted that it should be impossible to compare the integrated yield to the simulation if their shape is different. It was also suggested to check on the status of the septa, and see if the simulation has accounted for any possible changes in it.
		+
		+	==09/27/2018==
		+	Present: J.P., Karl, David
		+	'''Feature Presentations :
		+
		+	*David
		+	Showed several slides on the current status of the 2.5T packing fraction. Showed first a carbon slide showing better agreement, but still a few very jagged areas in the simulated carbon peak, and mentioned that he has defaulted to comparing dilution data with helium in it, as the optics data proved very hard to work with. J.P. mentioned that in addition to the jagged behavior at the top of the peak, it is worth looking into why the simulation peak seems wider than the production data very slightly at the base. Using the scale factor provided by this carbon comparison, David showed several slides of the resulting packing fractions, doing a linear fit to an 0.4 and 0.6 packing fraction simulated yield. J.P. and Karl gave several suggestions for dealing with the Helium elastic peak, since that has not been done yet. J.P. also suggested it was a good idea to take the whole Nitrogen peak when integrating to find the packing fraction, rather than just part of it. David mentioned he would also talk to Chao about the odd behavior at the top of the elastic peaks and ask for suggestions.  The packing fractions at this stage seem to give reasonable values, though everyone commented it will be important to subtract the Helium elastic peak before finalizing the packing fractions, and apply this same method to one of the 5T energy settings to compare to Toby's Ratio method.
		+
		+	Verbal Updates:
		+
		+	None
		+
		+	==09/13/2018==
		+	Present: Chao, J.P., David
		+	'''Feature Presentations :
		+
		+	None
		+
		+	Verbal Updates:
		+
		+	*Chao
		+	Working on smoothing out the acceptance correction for the 5T Transverse 2.2 GeV energy setting.
		+
		+	*David
		+	Showed a few slides, indicating that the proper cuts give very good agreement for the carbon data in the elastic region. However, it was discussed that there are many jagged peaks above this region that Chao says should not exist. Chao gave a few suggestions for improving the simulation's agreement. David also asked about how to scale properly by the luminosity, and how to actually put the packing fraction in the simulation, as the setting in the simulation only changes the energy loss according to Chao. J.P. and Chao explained that David should just scale the 0.6 packing fraction simulation by 0.6, and so on, but that each element would need to be scaled separately and added together (so for 0.6 packing fraction, total yield = 0.6 Nitrogen + 0.4 Helium + 0.6 Proton, etc). J.P. also suggested to try simulating an empty cell as the helium peak should be clean and match well.
		+
		+	==08/09/2018==
		+	Present: Chao, Karl, David
		+	'''Feature Presentations :
		+
		+	None
		+
		+	Verbal Updates:
		+
		+	*Chao
		+	Working on finishing transverse data, doing another replay, save root files on his local computer so it will not be diluted anymore, will calculate transverse acceptance soon. Won’t be at meeting next week, in two weeks will show final 5T 2.2 GeV transverse acceptance.
		+
		+	*David
		+	Working on comparison between carbon g2psim and data for 2.2GeV 2.5T, asked Chao a few technical questions about weighting the g2psim histograms in C++ or Python.
		+
		+	==08/02/2018==
		+	Present: Chao, J.P., Karl, David
		+	'''Feature Presentations :
		+
		+	*Chao
		+	Chao showed a few slides of final longitudinal acceptance correction, which he said look good except for a discontinuity at the start of the quasi elastic peak for longitudinal. Karl suggested checking the same plots with no dp cut just to compare. Chao also suggested that we make a repository of all g2p codes and simulations so that we can easily access whatever we need.
		+
		+	Verbal Updates:
		+
		+	*David
		+	David mentioned that he’s working on learning to use g2psim with Chao’s help, so that he can tweak it and produce simulated yields for use in the Oscar PF method.
		+
		+	==07/26/2018==
		+	Present: Chao, Karl, David
		+	'''Feature Presentations :
		+
		+	None
		+
		+	Verbal Updates:
		+
		+	*David: thanked Chao for sending g2psim, asked a few technical questions about operating it. Chao noted that it’s important to run each material seperately, so for production data, to run nitrogen, hydrogen, and helium independently and convolute them. David also showed the functional form of the uncertainty in g2 as a function of the uncertainty in the packing fraction, Karl suggested to provide rough numerical values and David agreed to do so next week.
		+
		+	*Chao: Sent David the current working version of g2p sim, very nearly done with 5T longitudinal acceptance. Will show cross sections for 5T longitudinal next week.
		+
		+	==07/19/2018==
		+	Present: Chao, J.P., Karl, David
		+	'''Feature Presentations :
		+
		+	*Karl
		+	Karl started off with some overview slides to try and get a majority of the work done by the end of the summer before people get busy. He voiced that the biggest question is whether we are using a data or model cross section, where the data is the attractive option if possible to make our results model independent, but the model may be a better option if the data is impossible or will take too long, as we can more or less publish the 5T data now, and the 2.5T data (pending pf analysis)
		+	He also asked if by the end of the meeting, we could identify all outstanding tasks and give an estimate for how long they will take to complete. Barring december, said that we should plan to have a paper submitted to PRL by the end of the year.
		+
		+	Moments paper work to be done yet: Low x contribution to BC integral
		+	Low nu contribution to gamma0
		+
		+	*David
		+	David showed a talk describing the Oscar Rondon packing fraction method. J.P. voiced that since the method requires scaling the simulation to carbon data, it cannot be used in the elastic region since you would need a different scale factor for carbon or nitrogen, so the only region to apply the method is the very inelastic one. Chao said right now he doesn’t think the simulation can do inelastic data, but that once he applies Ryan’s tweaked Bosted model, he thinks it will be able to. There was some discussion about the error bar for this packing fraction method, and J.P. said that the standard deviation of both the carbon and the production data in the chosen region would need to be applied to get the total error.
		+
		+	There was brief discussion of going back to the unfinished elastic fit method if all else fails, since all that should need to be done is finding a way to deal with quasi elastic contamination.
		+
		+	David also showed plots for the scattering angle for 2.5T 2.2GeV that show that even once the materials are separated out, all the data seems choppy at high E’ values.
		+
		+
		+	Verbal Updates:
		+
		+	*Ryan
		+	Finally, David relayed a few questions from Ryan. Karl said he doesn’t care which paper is published first and we should just publish them in the order we are able to. He also voiced that Ryan’s hyperfine question was something we could discuss offline or at the next meeting as time ran short. With regard to the question of using our cross sections, the eventual conclusion was that if Chao is able to match the timetable he provided today that it may be feasible to use g2p cross sections for all 2.2GeV energy settings.
		+
		+	*Chao
		+	Chao says within 2 weeks he can get cross section for longitudinal. Estimates within 1 month will have acceptance for 2.2 GeV, 5T Trans+Long, and another 6 weeks for 2.2GeV, 2.5T Trans. He said that 3.4 GeV has no elastic so he’s not sure there will be an acceptance. Karl and JP suggested he then prioritize the three 2.2GeV settings.
		+
		+	David estimated 6-7 weeks to get the packing fraction assuming we can get simulated yields. Chao agreed to send g2p simulation package to David so he can help with adding in missing models (Ryan Bosted-tweak?) and start learning to use it for applying the Oscar Method.
		+
		+	==07/12/2018==
		+	Present: Chao, J.P., Karl, Ellie, David
		+	'''Feature Presentations :
		+
		+	*Karl
		+	Showed the plots that he showed at Trento, and mentioned that there is a lot of interest right now specifically in the hyperfine result, as Ryan's calculation of delta 2 disagrees noticeably with the most recent papers. Said that we should try and get the paper out by the end of the year, so we should try and finish both acceptance and pf by the end of summer. Suggested that next week we sit down to figure out a game plan for how to do that.
		+
		+	Verbal Updates:
		+
		+	*David
		+	Mentioned that he and Karl got in touch with Oscar Rondon to ask a few questions about his packing fraction method, which we hope to try. Also said that he is currently re-playing the packing fraction rootfiles for several gradations of cut in case we want to study the cut dependence of the ratio method. Also working on producing plots for the scattering angle fit for just the carbon data, and for each production material independently. Karl asked Chao about how good the simulation is for the transverse settings, Chao said he has been focusing on the simulation for the 5T 2.2GeV settings but could maybe look into it.
		+
		+	*Chao
		+	Chao said he is continuing to work on the acceptance, and has been looking into the super-elastic peak J.P. asked about last week.
		+
		+	==05/31/2018==
		+
		+	Present: Chao, J.P., Karl, Ellie, David
		+	'''Feature Presentations :
		+
		+	*Chao
		+	Fit correction to the yield for 7 momentum settings in quasielastic region. Checked if the correction is stable and showed plot of yield for a 2.2GeV 5T run with the correction applied. J.P. says effective correction should be fine to fix relative difference. Discussed discontinuity at nu = ~459 MeV, Chao said he can fit that region to try and remove it. Karl asked about the motivation for the correction, Chao explained it is a fit that he found that works. See agendas section for plots.
		+
		+	Verbal Updates:
		+
		+	*David
		+	Still trying to work on packing fraction analysis. Modified code from Toby to re-add 5T settings, can nearly reproduce Toby's results but scaled down by a factor of 3.5 for all 5T energy settings. Sent an email to Toby and trying to look into what variable change could cause this difference between 2.5T and 5T.
		+
		+	==05/24/2018==
		+
		+	Present: Chao, J.P., Karl, David
		+	'''Feature Presentations :
		+
		+	None
		+
		+	Verbal Updates:
		+
		+	*Chao
		+	Still working on data corrections for the acceptance discontinuity, will have results next week. Also looked into beam position and found how to retrieve data from EPICS to help David, though warned that this does not give the real beam position, but the beam jumps should still show up in the raw data.
		+
		+	*David
		+	Working on packing fractions and the to-do list of suggestions Ryan left last week, is able to reproduce Toby's ratios, working on doing a fit to the scattering angle to determine how the simulation might change with the tighter cut. J.P. suggested that taking the average scattering angle required correcting the data to an average as well. David also mentioned that he fixed the issue with getting null results from Toby's code for 5T, but still cannot reproduce the 5T packing fractions correctly.
		+
		+	==05/17/2018==
		+
		+	Present: Chao, J.P., Karl, David
		+	'''Feature Presentations :
		+
		+	None
		+
		+	Verbal Updates:
		+
		+	*David
		+	Showed a few plots of the spread and average for each momentum setting involved in the asymmetry discrepancy analysis for the 2.5T data. However, J.P. noted that some of the means didn't quite make sense given the error bars of the points involved, and it became clear that there were a few mistakes in the normalization of the parameters for these plots. Further, differences between the global run by run asymmetry plot and the momentum-setting ones lead to the conclusion that there must have been a mistake in the presentation of the plots. David said he would re-do this section of the analysis more carefully and try again next week to determine if any of the momentum settings seem pathological.
		+
		+	==04/26/2018==
		+
		+	Present: J.P., Karl, David
		+	'''Feature Presentations :
		+
		+	None
		+
		+	Verbal Updates:
		+
		+	*David
		+	Showed a reprisal of his update on the Left and Right HRS Asymmetry comparison for the 2.2 GeV 2.5 T data to catch J.P. up, and mentioned that he will produce a plot of total asymmetry plotted against run number by using a run by run asymmetry, at Ryan's suggestion. J.P. and Karl both agreed that it would not be wholly unacceptable to add a systematic to the moment data if the issue could not be resolved otherwise, but that it would be ideal to solve it and not have to do that. J.P. also suggested that since the asymmetry seems to be unstable for both arms around the relevant point, that perhaps something happened with the beam, and suggested cross comparing to Jie's BPM analysis to try and determine if there was a beam jump or something similar around the time that the inconsistency occurs.
		+	Also showed a table of packing fractions generated from Toby's scripts with different acceptance cuts. Said that the inclusion/exclusion of the RunStatus 6 Packing Fraction runs seems to have little impact on the Packing Fractions generated, but that using Ryan's tight cut in place of any of Toby's loose cuts produces packing fractions for the 2.2 GeV 2.5 T setting that seemed to Karl to be more reasonable. J.P. and Karl both suggested that one standard cut should be used for everything, preferably Ryan's tight cut since that has been well documented and discussed already. David said he will produce a re-done version of Table 6.4 from Toby's thesis, with all of the packing fractions generated using Ryan's tight cut.
		+
		+	==04/05/2018==
		+
		+	Present: Chao, David
		+	'''Feature Presentations :
		+
		+	None
		+
		+	Verbal Updates:
		+
		+	*Chao
		+	Still working on trying to resolve acceptance issue, before J.P. left for China he advised that Chao try cuts on various variables that go into the acceptance, like the Raster and the BPMs, to try to quantify what the effect on the acceptance is. Chao said he is currently working on doing this.
		+
		+	*David
		+	Said that he compared error bar on Gamma 2 to the variation in Gamma 2 caused by the discrepancy in the asymmetry between the left and right arms for the 2.5T 2254 MeV data, and that the total errorbar (statistical+systematic) is about 33% of the value of the moment, while the discrepancy causes a 20% change, for comparison. Also discovered that Toby's rootfile code appears to produce root files formatted differently from the ones his packing fraction script calls so working on eliminating the differences so that they can actually run together.
		+
		+	==03/29/2018==
		+
		+	Present: Karl, David
		+	'''Feature Presentations :
		+
		+	*David
		+	Presented an update on the 2.5T 2254 MeV data asymmetry comparison, showing the result of replaying the data with a tighter momentum cut. Unfortunately, the tighter momentum cut seems to worsen the chi^2 comparison rather than improve it. Also showed and discussed with Karl an attempt to determine how serious the effects of the asymmetry discrepancy are on the final value for Gamma 2. The discrepancy seems to be responsible for a 20% variation in Gamma 2, but Karl said this value should be compared to the size of the existing error bar to determine if just throwing a systematic on and using the original data would be a valid way to go. Also re-showed the comparison of data taken on the first sweep up the momentum spectrum to data taken going back down, and showed that the largest discrepancy only occurs on the second set of runs, though no glaring change is notable in the log book.
		+
		+	David also mentioned that he's started work on trying to replay Toby's root files to re-generate the packing fractions for the 2.5T data.
		+
		+	Verbal Updates:
		+
		+	None
		+
		+	==03/23/2018==
		+
		+	Present: Chao, David
		+	'''Feature Presentations :
		+
		+	*Chao
		+	Trying to resolve the issue Ryan discovered with acceptance not being continuous for production runs, using Dummy run to try and look at background and subtract out the effects of the target cell itself, runs are scaled by live charge so are proportional to cross section, so can be subtracted. This subtraction removes everything outside the target cell, effectively, the background, but does not consider the difference between foil target and extended target. Cut simulated target into 1mm slices to investigate-- for real target, there is no cross section difference between z=0, z=-13, and z=13, for any kinematic variable. Chao's conclusion is that either simulation doesn't match well, *or* the acceptance should not be dependent on the z position in the target. See slides attached to agendas section.
		+
		+	Verbal Updates:
		+
		+	*David
		+	Left arm replay finished and asymmetries regenerated for 2.5T 2.2GeV runs, ran into issue with many of the right arm runs failing repeatedly on the batch farm. Going to try running interactively with Screen and using a different queue to avoid timeouts.
		+
		+	==03/09/2018==
		+
		+	Present: Ryan, J.P., Karl, David
		+	'''Feature Presentations :
		+
		+	None.
		+
		+	Verbal Updates:
		+
		+	*Ryan
		+	Still waiting on Chao to get back to him about cross section issue, said Chao's explanation makes sense to him. J.P. asked about question dealing with the Y acceptance, but Ryan commented that he hasn't talked to Chao about it yet. Ryan agrees that the target length is the only thing different between carbon and production runs and that this is likely the source of the cross section issue.
		+
		+	*David
		+	Replay finally working, ran into issue with some of the files coming out un-filled from the batch farm, but this is an issue Ryan has seen before and Ryan advised that he replay just the failed runs repeatedly until all of them function.
		+
		+	==11/27/2017==
		+
		+	Present: Ryan, Ellie, J.P., Karl, David
		+	'''Feature Presentations :
		+
		+	None.
		+
		+	Verbal Updates:
		+
		+	*Ryan
		+	Discussed progress on the PRL with Karl and J.P., and whether or not the acceptance should be included.
		+
		+	==11/17/2017==
		+
		+	Present: Ryan, Ellie, J.P., Karl, David
		+	'''Feature Presentations :
		+
		+	None.
		+
		+	Verbal Updates:
		+
		+	*Ryan
		+	Corresponding about Hyperfine results with Franziska Hagelstein, got numbers for delta_1 and delta_2, Karl suggested that this is good but evidence that since Ryan's data is on the Arxiv, people are going to want to use it and this is more incentive for us to be expedient in getting to publish. Ryan is working on finishing the hyperfine paper and intends to include both 2.2 GeV 2.5 T data, and the g1 point.
		+
		+	*Karl
		+	Has approved Toby's thesis, after edits that provide more detail on the choice of the ratio method over the fit method for the packing fractions.
		+
		+	*David
		+	Still working on tight dp cut replay, has all of Toby's dilution and packing fraction scripts running locally, Ryan and Karl suggested trying to replay dilutions with a tighter acceptance.
		+
		+	*Chao
		+	Trying to get acceptance study running on JLab batch farm. Longitudinal study for the acceptance is done.
		+
		+
		+
		+	==10/27/2017==
		+
		+	Present: Ryan, Ellie, J.P., David
		+	'''Feature Presentations :
		+
		+	*Chao
		+	Acceptance study for the longitudinal settings is just about finished. Elastic peak agrees well with theory, continuity of nu spectrum is good. Needs a conversion between slow and fast raster current. Transverse spectrum has not as good continuity, will be fixed soon.
		+
		+	Verbal Updates:
		+
		+	*David
		+	Still working on tight dp cut replay, showed proof of principle doing dp cut on bin by bin basis, that seems to give more evidence that this is the issue, but aims to make it better with the count by count replay.
		+
		+	*Karl
		+	Showed plots of g2p packing fractions vs SANE packing fractions, discussed the elastic fit method with Toby to determine that the .3 packing fraction is not good, but wants to investigate the suspiciously high 2.5T packing fractions, since SANE data never goes above .74.
		+
		+	==10/06/2017==
		+
		+	Present: Ryan, Ellie, J.P., David
		+	'''Feature Presentations :
		+
		+	None
		+
		+	Verbal Updates:
		+
		+	*Ryan
		+	Working on the PRL for the ChiPT paper, just started.
		+
		+	*David
		+	Working on resolving systematic shift in 467 Nu point for 2.2 GeV 2.5T asymmetry between left and right HRS, showed normalized yields, J.P. and Ryan suggested a tight dp cut. Also discussed the suspiciously good chi^2 generated with the method J.P. suggested before, J.P. said he thinks it is fine that the chi^2 is small but that it is necessary to evolve the kinematics of one arm to the other one before combining the 2.5T asymmetries. Also mentioned working on a cross check for the 5T data for g2 with Toby and Ryan, but has a sign error, it was suggested for David to fix the sign of the asymmetry to the theory or the elastic asymmetry peak.
		+
		+
		+	==09/22/2017==
		+
		+	Present: Ryan, Chao, Ellie, Karl, David
		+
		+	'''Feature Presentations :
		+
		+	None
		+
		+	Verbal Updates:
		+
		+	*Ryan
		+	Sent model codes to David, discussed dilution's odd behavior at nu > 1000 MeV, explained that previously he and Toby have switched to a model above 950 MeV abruptly from data. Said that packing fraction systematic error doubled after Toby fixed the radiative correction issue. Karl and Ryan discussed the issue of Toby assuming the ratio of carbon to nitrogen was a flat 15%, where Ryan was able to find a paper plotting it vs W.
		+
		+	*Chao
		+	Unable to speak, but will present 5T 2.2 GeV acceptance next week.
		+
		+	*David
		+	Has generated g2 for 2.5T 2.2GeV data, will refine over the coming week.
		+
		+	==09/06/2017==
		+
		+	Present: Karl, J.P., David, Ellie
		+
		+	'''Feature Presentations :
		+
		+	*David
		+	Showed a study on the left and right arm HRS asymmetry comparison for 2.5T. Was able to replicate Ryan's results for 5T asymmetries, J.P. and Karl suggested redefining the chi^2 in terms of the uncertainty of both arms to remove ambiguity. 2.5T 2.2 GeV asymmetries show good agreement with the exception of three data points, which David is investigating, after noting that the runs going into those data points jump by about 5 days and change target material. Karl and J.P. suggested it was also important to obtain information about whether Toby's dilutions should change based on the target material. More details on his slides can be found [https://hallaweb.jlab.org/wiki/images/4/43/G2pHRSCompare.pdf here].
		+
		+	Verbal Updates:
		+
		+	None
		+
		+	==08/23/2017==
		+
		+	Present: Ryan, J.P., Toby, David, Alexandre
		+
		+	'''Feature Presentation :
		+
		+	None
		+
		+	Verbal Updates:
		+
		+	*Ryan
		+	Discovered the the divergence in XS from Toby was because the radiation lengths were flipped in Toby's analysis-- TA comes after TB (T after and T before). Toby promised to re-run the code and ensure
		+
		+	*David
		+	Working on Left+Right HRS 2.5T comparison still, trying to get Chi^2 for 5T comparison to be as good as in Ryan's analysis. Using same runs, LHRS asymmetry agrees with Ryan's but RHRS differs for three data points.
		+
		+	==08/09/2017==
		+
		+	Present: Ryan, Chao, J.P., Karl, David
		+
		+	'''Feature Presentation :
		+
		+	None
		+
		+	Verbal Updates:
		+
		+	*Chao
		+	Working on optics runs to complete acceptance study, trying to figure out a way to work around not having definitive BPM Results.
		+
		+	*Ryan
		+	Trying to get signatures from committee on thesis, still waiting to hear back from Toby about dilution issues.
		+
		+	*David
		+	Working on Left+Right HRS 2.5T comparison, have preliminary results but with a very large Chi^2 of ~25, trying to work on account for second order effects to knock that down and make sure it is viable to combine the data from both arms.
		+
		+	==08/02/2017==
		+
		+	Present: Ryan, Karl, David, J.P.
		+
		+	'''Feature Presentation :
		+
		+	None
		+
		+	Verbal Updates:
		+
		+	*David
		+	Still working on HRS asymmetry comparison for the LHRS and RHRS, installing ROOT and configuring local coding environment. Ryan agreed to help guide David through setting up his environment.
		+
		+	Discussed intelligent magnet power supply, which David will investigate communicating with via USB, irrelevant to the g2p collaboration.
		+
		+	*Ryan
		+	Thesis edits essentially complete, L+R HRS Comparison had an angle difference of .3 degrees
		+	Ryan and Karl discussed trying to get a better dilution and packing fraction from Toby to deal with other issues in 2.5 T 2.2 GeV data
		+	Ryan should be able to get shell of Hyperfine results soon
		+
		+	*Karl
		+	Karl asked Xiaochao to contact Jie about finishing the BPM analysis, Jie responded that he will not finish the analysis.
		+	In terms of administrative issues, Karl agreed to add David to g2p mailing list so that he can take over sending out weekly meeting emails from Ryan.
		+
		+	==07/19/2017==
		+
		+	Present: Ryan, Toby, Karl, David
−	*Pengjia	+	'''Feature Presentations :
−	**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].	+
	*Toby		*Toby
−	**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].	+	Showed an update on the dilution and packing fraction calculation for 2.5T. This is an issue at large nu where the fit to the packing fraction and dilution grow large where the model expects them to level off. Toby thinks this might be an issue with the radiative scale factor he is applying to the data. There is also some questions about the choice of acceptance cut used to generate the quantities. He chose a large acceptance cut to improve statistics but this might have systematic effects causing the rise. He will repeat the analysis at a few difference acceptance cuts to check this effect.  More details on his slides can be found [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/2Tdilution_071917.pdf here].
−	*Melissa	+	Verbal Updates:
−	**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 <br> be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_07_08.pdf here].	+
−	*Min	+	*David
−	**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].	+	Working on HRS asymmetry comparison for the LHRS and RHRS
		+
		+	==07/12/2017==
		+
		+	Present: Ryan, Toby, Karl, Ellie, David, Chao
		+
		+	'''Feature Presentations :
		+
		+	*Ryan
		+	Showed beam energy values for the experiment run period on production runs. There are some  bigger than expected fluctuations. To first order the effect of this is small (Mott XS variation) but the question is how this could effect calibrations, such as the BPM calibration. More details on his slides can be found [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_071217.pdf here].
		+
		+	Verbal Updates:
		+
		+	*Toby
		+	2.5 T packing fraction values. Taking into account yield drifts gives a systematic error on the order of 15% at 2.2 GeV 2.5 T. Looking into 1.7 GeV settings next
		+
		+	*David
		+	Working on HRS asymmetry comparison for the LHRS and RHRS
	*Chao		*Chao
−	**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].	+	Working on acceptance simulation. Running simulation for the production runs. Slow going because he can only runs a handful of jobs at a time.
		+	==07/05/2017==
−	==7/1/2015==	+	Present: Ryan, Karl, Toby, J.P., Chao, David
−	Present: Chao, Vince, Jie, JP, Min, Melissa <br>	+	General Discussion:
−	By Phone: Pengjia <br>	+
−	'''Feature Presentations:'''	+	*Batch farm is prioritizing multi-threaded jobs so this will impact g2p replay and also Chao's acceptance simulation timeline.
−	*Min	+	*Toby is going to start looking at the 2.5T dilutions this week.
−	**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].	+
−	*Pengjia	+	*David has generated asymmetries but results are consistent with zero so he will try larger binning (up from 10 MeV)
−	**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].	+
−	==6/24/2015==	+	==06/28/2017==
		+	Present: Ryan, Toby, David, Karl, Chao, JP, Alexandre, Xiaochao, Ellie
−	Present: JP, Min, Chao, Jie, Jixie<br>	+	General Discussion:
−	By Phone: Vince, Toby, Ellie, Pengjia, Karl <br>	+	*2.5T data quality. Based upon error bars from a quick moment analysis of the 2.5T data from Ryan it appears that the 2.2/1.7 GeV data is useful for publication with Q2 values of approx 0.04 GeV2 and 0.02 GeV2, respectively. The 1.1 GeV data error bars are very large, which is in part due to the very small asymmetry prediction at that low Q2 (0.009 GeV2).
−	'''Feature Presentations:'''	+	*Toby is leaving to start a job on July 24. He will try and get something together for the dilution and packing fraction analysis for the 2.5T settings.
		+
		+	*Chao is making good progress with the longitudinal acceptance for the carbon data. He is able to produce a continuous spectrum with good agreement in the overlap regions at large nu. Unfortunately there is no overlap around the delta-resonance. He will do a similar study except at the transverse settings next.
		+
		+	*David is going to work on the data quality check for the 2.5T asymmetries. His first step is to produce g2p asymmetries and compare to results from Ryan and Toby.
		+
		+	==06/21/2017==
		+	No meeting because of Hall A collaboration meeting.
		+
		+	==06/14/2017==
		+
		+	Present: Ryan, Karl, Toby, J.P.,Chao
		+
		+	'''Feature Presentation :
		+
		+	*Ryan
		+	Showed the results of a quick analysis of the 1.7 and 1.1 GeV 2.5 T settings. The 1.7 GeV data looks pretty good and can most likely be used going forward. There is one momentum setting just previous to the delta where the majority of the data was taken with a mismatched septa and dipole configuration, so it is not included in these slides. He will try including this data to see the effect it has on the results. It should probably be OK for the asymmetry. The 1.1 GeV data looks worse statistically, which related to the much smaller asymmetry that we see as we go to lower and lower Q2.  As we go to lower Q2 we also have the added complication of the Christy fit we're using for the unpol XS getting worse and worse. Going forward Ryan will do a quick moment analysis of this data. More details on his slides can be found  [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_061417.pdf here].
	*Toby		*Toby
−	**Presented some asymmetry plots which Ryan will show in the Chiral Dynamics conference.<br> The plots can be seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/asymplots.pdf here]. All statistics has been included in these plots along with<br> the dilution and the polarizaiton results. The calculated asymmetries is compared with fully<br> radiated MAID model. Toby will continue working on the physics asymmetries of all the<br> kinematics settings.	+	Showed different methods for calculating the low-x portion of the BC sum rule. These include the polarized PDF's and Hall B model. The problem is that none of these methods are really applicable at the g2p kinematics (PDF's hold down to Q2 = 1 GeV2), and that the low-x portion of the integral must be a sizable contribution for the BC sum rule to hold. Going forward we will most likely assume that the BC sum rule holds and use that assumption to place a limit on the low-x behavior of g2 at low Q2. More details on his slides can be found [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/bcsum_unmeasured_061417.pdf here].
		+
		+	==06/07/2017==
		+
		+	Present: Ryan, Karl, Toby, J.P.,Chao, Ellie
		+
		+	'''Feature Presentation :
		+
		+	*Ryan
		+	Showed the results of a quick analysis of the 2.2 GeV 2.5 T settings. The goal of this analysis was to check the overall quality of the data  and includes the combined statistics of both the RHRS and LHRS. The overall statistical precision of the data is pretty good considering the much lower target polarization of the 2.5T settings (15% on average compared to the 70% for the 5T runs). Going forward he will do a similar study for the 1.1 GeV and 1.7 GeV settings and also complete a very preliminary moment analysis of these settings. These settings also need a completed dilution and packing fraction analysis  [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_060717.pdf slides].
		+	Verbal Updates:
	*Jie		*Jie
−	**Gave an update on his study of the acceptance. He studied the multiple scattering effect<br> of the incoming beam. The standard deviation of this effect is ~0.07mm for position and<br> ~0.7mrad for angle. He also studied the influence of the beam position to the acceptance.<br> There was a large dependence on y_tg (horizontal direction) but not on x_tg (vertical direction).<br> 2-D plots shows that the acceptance is not uniform along the vertical direction. JP suggests <br> that the horizontal target field may be a reason of this effect. More details can be seen in <br> his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_06_24_simulation/2015_06_25_Simulation_update.pdf here].	+	Published his BPM tech-note update to the wiki.
−	==6/17/2015==	+	*Chao
		+	Summarized his acceptance study progress. So far he has applied his 8mm raster cut method (+/- 15mrad in ph and 20 mrad in th) to the elastic carbon long. setting and gets 5% agreement between the simulation and data. He is able to drastically reduce the uncertainty in the raster cut by cutting on current and not size. The timing information of the raster is known very well. He knowns the time the raster spends inside the area of the cut and the time it spends outside. The ratio between these two times is scaled to the total charge. He is currently applying this to all the carbon dilution data at longitudinal to see how this procedure works at other P0. He estimates this will take 2-3 weeks. After that he will move onto the transverse setting and estimates that will take an additional 1-2 months to complete.
−	Present: JP, Min, Jie, Chao, Melissa<br>	+	==05/31/2017==
−	By Phone: Alex, Ryan, Toby, Ellie, Pengjia, Vince <br>	+
−	'''Feature Presentations:'''	+	Present: Ryan, Karl, Toby, J.P.,Chao
		+
		+	'''Feature Presentation :
		+
		+	*Toby
		+	Showed an update on his g2 moment calculations. His moments included the BC sum rule and also DeltaLT. From his analysis it was concluded that it is very difficult to verify the BC sum rule at low Q2 because of the lack of data at low x. The DeltaLT results look much better. More details on his slides are found [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/g2moments_talk_053117.pdf here].
		+
		+	Verbal Updates:
		+	*Jie
		+	Still working on his BPM tech-note/update.
		+
		+	*Chao
		+	Planning on talking with JP about his acceptance study update. Had to leave early to go to another meeting.
		+
		+	==05/24/2017==
		+
		+	Present: Ryan, David, Karl, Toby, J.P., Jie, Ellie
		+
		+	'''Feature Presentation :
		+
		+	None
		+
		+	Verbal Updates:
		+
		+	*Jie
		+	Still working on his BPM tech-note/update. Hopes to have it done by next week. This might also be his last g2p meeting before he starts his new job. Will also add his thesis to the wiki.
		+
		+	==05/17/2017==
		+
		+	Present: Ryan, David, Karl, Toby, J.P. Chao
		+
		+	'''Feature Presentation :
	*Ryan		*Ryan
−	**Working on inelastic polarized radiative corrections, based on the formalism by Akushevich, <br>Ilyichev and Shumeiko. Since there is no polarized proton data yet, he is using models to <br>understand the systematic error on the radiative corrections. He used the MAID 2007 model to <br>generate the polarized cross sections, and went through the same iterative process he used for <br>the unpolarized radiative corrections.  To do the systematic study he took the MAID 2007 cross <br>sections, radiated them using the POLRAD code, unfolded/radiatively corrected the cross sections, <br>then compared them to what he started with; the difference is attributed to systematic error. In <br>general, the ratio of unfolded/radiated cross section is close to 1, but there is a jump when &Delta;&sigma; <br>crosses zero. JP suggested an alternate method of doing the corrections is the correct on the spin <br>up XS and spin down XS separately, since neither will be zero. Ryan will look into this method as <br>a cross check. More details can be seen in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_061715.pdf here].	+	Showed an analysis for an explanation for why the 2.2 GeV Longitudinal polarized DS does not go to zero below the pion production threshold after tail subtraction. His idea is that the elastic radiative events come from a different part of the acceptance than the inelastic events. This effect could be potentially large if a large acceptance cut is used. The big unknown in this analysis is what is the exact angle difference. With the current reconstruction/simulation status it's very difficult to determine. In the future, if the simulation is able to reproduce the angular acceptance then the tails can be calculated and weighted for the simulated acceptance. This also raises potential problems for getting a polarized DS from an asymmetry and cross section calculated with different acceptance cuts. For now, the analysis will proceed with the old method and assume one scattering angle. Ryan will check the results of using a tight asymmetry and tight cross section cut to see how the tail subtraction is effected. More details on his slides are found [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_051717.pdf here].
−	**Working on his talk for Chiral Dynamics, he will send out his slides to the collaboration later <br>this week.	+
		+	*Chao
		+	Showed an update on the optics simulation and he is currently trying to beat down the systematic error from making a raster cut. He is currently cutting on raster current as opposed to raster size to improve the uncertainty. With a raster cut the simulation is much better able to reproduce the data.
		+
		+	==05/10/2017==
		+
		+	Present: Ryan, Jie, David, Toby, Ellie, JP
		+
		+	'''Feature Presentation :'''
		+
		+	*Ryan
		+	Showed an analysis update of the results section of his thesis and includes analysis of all of the 5T settings. He evaluated the g1 moments and the hyperfine splitting contributions for g1 and g2.  More details on his slides are found [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_051017.pdf here].
		+
		+	==05/03/2017==
		+
		+	Present: Ryan, Jie, David, Karl, Toby, Ellie, JP, Chao
		+
		+	'''Feature Presentation :'''
		+
		+	*David
		+	Showed an update for calculating the acceptance correction by normalizing to the elastic cross section. His uncertainty in this method is slightly better than the results Toby showed before and his dominant uncertainty is the scattering angle reconstruction and it's effect on the Mott XS and elastic form factors. He will look into further separating the quasi-elastic and elastic peaks by subtracting out the elastic tail for helium-4. More details on his slides are found [https://userweb.jlab.org/~rbziel/Weekly_Meetings/xsscalefactor.pdf here].
		+
		+	==4/26/2017==
		+
		+	Present: Ryan, Jie, David, Karl, Toby, Ellie
		+
		+	'''Feature Presentation :'''
		+
		+	*Ryan
		+
		+	Showed results of a parallel asymmetry analysis between Toby and Ryan. The asymmetries agree very well and the only slight difference is at the longitudinal setting. This difference is a result of slightly different acceptance cuts used in the analysis and goes away if the same cuts are used.  More details on his slides are found [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_042617.pdf here].
	*Toby		*Toby
−	**Working on fixing the scattering angle dependence on the cross section.  His original method <br>was to plot the calculated scattering angle, take the central value and plot it versus HRS <br>momentum.  Fitting this with an exponential function (originally provided by Jixie), he could <br>then use the fit parameters in the Bosted model to calculate the cross section. The problem <br>with this method is it forces the scattering angle across kinematics to be continuous, but our <br>data is not continuous.  He generated the model at all scattering angles within a momentum <br>setting and combined all resulting models with a weighted average.  This causes the model to be <br>discontinuous over an energy setting, but this method of generating the model may be necessary <br>since the continuous model doesn't represent our data well.  JP cautioned that the acceptance <br>could have an effect on the scattering angle, so we must be cautious using this data until <br>optics/acceptance studies are finalized.  More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/anglecorrection.pdf here].	+	Posted an update on last weeks slides to include a model comparison to his calculated cross sections. His slides are found [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/xs_talk_042617.pdf here].
−	*Min	+	==4/19/2017==
−	**Gave an update on her acceptance study. She divided the data by the Mott cross section before <br>comparing it to the simulation results for an empty dilution run (just helium). For the scattering <br>angle she is using the survey result, which has an uncertainty of 0.7mrad. JP commented that we must<br>be cautious in how we determine the scattering angle, particularly the effect of the septum magnet <br>on the angle. For next time, Min will work on tuning the apertures to have better agreement between <br>data/simulation. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/06172015/06172015.pdf here].	+
		+	Present: Ryan, Jie, David, Karl, Toby, Ellie, Chao<br>
		+
		+	'''Feature Presentations :'''
		+
		+	*Toby
		+
		+	Showed a comparison between calculating polarized cross sections using a model and using data. In the data method he multiplies the raw asymmetry by the raw cross section with no dilution correction. In the model method he applies the dilution to the asymmetry and then uses a unpolarized proton model (radiated). The two results agree pretty well except for the 3.3 GeV setting where the yield drifts present problems with the dilution and cross section calculation. We will most likely have to use a model at this setting. More details on his slides are found [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/xsdiff_041917.pdf here].
		+
		+	Verbal Updates:
	*Chao		*Chao
−	**Gave a status update on optics, specifically the offset problem he has discussed previously. He <br>treats the matrix elements separately and uses the center hole to determine the offset and 2 first <br>order matrix elements.  He then uses the beam position scan data to determine matrix elements that <br>are not related to x<sub>fp</sub> and delta scan data to determine the matrix elements related to x<sub>fp</sub>. <br>However, using the updated matrix (for the 1.7 GeV data) still has a 3mm offset.  JP questioned <br>whether the effect of the septum is being taken into account properly. Once we understand how to <br>treat the septum well, we'll know whether to attribute problems to the septum field, target field, <br>etc.  Chao will go back and look into the effect of the septum before moving forward on the offset <br>problem.  More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/Chao_WeeklyMeeting_06172015.pdf here].
		+	Talked about using the raster cut in the simulation to match data and simulation for the acceptance. He's going to soon try and apply this raster cut method across the momentum settings at the longitudinal setting and see how well the simulation can match data. He's currently using a 30 mRad phi cut, which is significantly larger than the cut Toby is using and will the systematic uncertainty from knowing the cut boundary. There is going to be an additional systematic from using a raster cut when it comes to calculating the accumulated charge. He is looking into this.
−	'''General Discussion:'''	+	==4/12/2017==
−	*The abstract deadline for DNP is July 1st.	+
		+	Present: Ryan, Jie, David, Karl, Toby, JP, Ellie<br>
−	==6/10/2015==	+	No presentations this week. Toby and Ryan are working on comparing their asymmetry results to confirm that their methods agree. Jie's graduation date is May 9 and he is still working on finishing up his thesis.
−	Present: JP, Min, Chao, Jie, Kalyan, Melissa<br>	+	==3/29/2017==
−	By Phone: Vince, Ryan, Toby, Ellie, Pengjia, Karl <br>	+
−	'''Feature Presentations:'''	+	Present: Ryan, Jie, David, Karl, Toby, JP, Chao, Ellie<br>
−	*Jie	+	'''Feature Presentations :'''
−	**Gave an update on his study of the change in acceptance/yields due to shifts in the <br>beam position using simulation.  Last time he showed the number of events blocked by <br>different components such as the collimators, and magnet entrance/exit planes. He looked <br>at the change in acceptance/yields moving along BPM Y and X and found that there was <br>not a large dependence on Y, but the dependence on X was significant. In addition, <br>removing the Q1 exit plane aperture while moving along BPM X showed a large effect on <br>acceptance/yield ratio on the positive x side.  He also looked at the effect of extending <br>X to +30mm.  He found that moving the target ~10mm gives the largest acceptance at the <br> Q1 exit endplane.  There was some confusion about coordinate definitions, Jie will clear <br>this up for next time.  More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_06_09_simulation/2015_06_10_Simulation_update.pdf here].	+
		+	*Ryan
		+	Showed an update including the Gamma1 and GDH moment calculations. The results have very good statistical error bars when compared with the Hall B data and also his integration of the Hall B data agrees with the published Hall B results. More details can be found in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_032917.pdf here].
−	==5/27/2015==	+	*Chao
		+	Showed an update on the simulation for Run 5612. He is able to reproduce the edges of the acceptance better if he places a very tight cut on the raster size. This suggests a beam position reconstruction issue. Going forward he is going to look at the uncertainty introduced by this raster cut and see which has the larger contribution to the uncertainty: raster cut or acceptance cut. More details can be found in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/weekly/Chao_WeeklyMeeting_20170329.pdf here].
−	Present: JP, Min, Jie, Chao, Jixie, Melissa<br>	+	==3/22/2017==
−	By Phone: Pengjia, Ryan, Toby, Ellie, Alexandre<br>	+
−	'''Feature Presentations:'''	+	Present: Ryan, Jie, David, Karl, Toby, JP, Chao<br>
−	*Pengjia	+	'''Feature Presentations :'''
−	**Comparing calculated asymmetries from data to asymmetries calculated from the MAID model. <br>He looked at the 2.2 GeV, 5T settings (both longitudinal and transverse) and used a dilution <br>factor of 0.15.  He needed to scale the MAID model as it was 6X larger than the asymmetries <br>calculated from data.  He also included a plot of Q&sup2; vs W for each setting.  JP commented <br>that the distribution was a little strange, since Q&sup2 and W are directly correlated the <br>distribution shouldn't decrease or stay flat.  More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/05272015/maid_asym_20150527.pdf here].	+
−	*Min	+	*Ryan
−	**Gave an update on acceptance studies, specifically the 3rd septum setting. In this septum <br>configuration, the entire second coil is gone.  She looked at groups of runs where the beam <br>position was stable to determine the uncertainty of the focal plane measurement.  She compared<br>the y and &phi; at the center sieve hole at the focal plane determined from data to the SNAKE <br>result. The center sieve hole was defined by survey results.  JP suggested using the no-target <br>field setting as a starting point to determine the offset, then look at the transverse effects. <br>More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/05272015/05272015.pdf here].	+	Showed a comparison between the Bosted model and low Q2 SLAC data. The agreement between data and the model is better at larger Q2 and around 15% at the 5T setting kinematics. Ryan is waiting on an updated model from Eric Christy that includes the low Q2 data in the fit. More details can be found in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_032217.pdf here].
		+	*Toby
		+	Also showed a comparison between the Bosted model and the SLAC data but included a preliminary g2p cross section as well. The agreement is at the 15% level with our data. More details can be found in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/xs_talk_032217.pdf here].
−	'''General Discussion:'''	+	*David
−	*There will be no meeting next week due to the Users Group Meeting.	+	Showed a method for calculating the helium-4 elastic cross section from g2p empty dilution runs. He compares the g2p data to the Rosenbluth result from the MSW (McCarthy-Sick-Whitney) form factors and get's agreement at the 10% level. He will look into adding systematic uncertainty estimates to both his measured and calculated quantities. He will also investigate the 'Delta E' term in the elastic peak radiative corrections. More details on his slides can be found [https://userweb.jlab.org/~rbziel/Weekly_Meetings/he4crosssectionanalysis3.pdf here].
		+	Verbal Updates:
−	==5/20/2015==	+	A request was made by Eva-Maria Kabuss for some g2p slides to present at DIS 2017 (April 3-7).
−	Present: JP, Min, Jie, Jixie, Melissa<br>	+	==3/15/2017==
−	By Phone: Pengjia, Ryan, Toby, Kalyan<br>	+
−	'''Feature Presentations:'''	+	Present: Ryan, Jie, David, Karl, Toby, JP, Chao, Ellie<br>
−	*Pengjia	+	'''Feature Presentations :'''
−	**Calculated asymmetries using the MAID model. He used the total cross section output from <br>MAID 2007, then summed the cross sections from two channels to extract the asymmetry. He <br>calculated the longitudinal/transverse asymmetries and g1,g2,F1 and F2 for several different <br>values of Q&sup2;.  Ryan pointed out that the calculated asymmetries cannot be compared directly <br>to our data, since our data is not at constant Q&sup2;, and the MAID model is not radiated. More <br>details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/05202015/maid_asym.pdf here].	+
		+	*Chao
		+	Showed an update on the optics and acceptance simulation. He showed that for a carbon run with no liquid helium and at the longitudinal target configuration he is able to match data to simulation with a very tight acceptance cut. He is working on expanding this cut to reduce the overall systematic uncertainty in the acceptance. Super elastic events and carbon excited states make expanding this range difficult. More details on his slides can be found [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/weekly/Chao_WeeklyMeeting_20170315.pdf here].
		+
		+	Verbal Updates:
		+	*Jie
		+	Graduation date is set for May 9, 2017.
		+
		+	==3/8/2017==
		+
		+	Present: Ryan, Jie, David, Karl, Toby, JP<br>
		+
		+	'''Feature Presentations :'''
		+
		+	*Ryan
		+	Showed an update on how he is extracting g1 from the longitudinal data and evolving it to a constant Q2. He also showed a preliminary calculation of the gamma0 moment, which agrees well with the current Hall B measurements and chiral perturbation theory predictions. More details on his slides can be found [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_030817.pdf here].
		+
		+	==3/1/2017==
		+
		+	Present: Ryan, Toby, David, Jie, JP, Karl, Ellie, Chao<br>
		+
		+	'''Feature Presentations :'''
		+
		+	*Ryan
		+	Showed an update on the systematic error analysis going into the asymmetries, polarized cross sections and radiative corrections. Currently the dominating systematic error is from the angle reconstruction and use of an unpolarized model to create the polarized cross sections. The angle reconstruction error is amplified at low angles because of the strong Mott dependence. The unpolarized cross section systematic could be reduced in the future by substituting in g2p data for that component. More details on his slides can be found [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_022917.pdf here].
	*Jie		*Jie
−	**Investigating the field overlap of the septum and Q1 fields in the SNAKE model. Currently, <br>no overlap is assumed between the two fields.  He looked at different points in the space <br> between the septum and Q1 entrance to check the field from each magnet. Although the Q1 <br>field goes to zero close to the septum, the septum field extends to the entrance of Q1.  The <br> current septum field map is too small to cover the full area in the x,z direction, so a larger <br>field map is needed. JP also suggested looking at how this will change the particle <br>trajectories; Min will work on estimating this for next time. More details can be seen in <br>Jie's slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_05_20_snakefield/2015_05_20_hrsfield_update.pdf here].	+	Gave an update on the BPM calibration process. Showed that there is a strong position dependence to the off-sets determined from Harp scans. Through the reconstruction procedure he is unable to reproduce the location of the harp scan points because of this position dependence. More details on his slides can be found [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2017_0301_plots/yields_update_20170301.pdf here].
		+	*Toby
		+	Presented the status of the dilution analysis for the 3.3GeV settings. The analysis is complicated by the large yield drifts seen in the data. He is still trying to figure out a method to give reasonable dilution results at this setting. But whatever method he settles on will most likely come with an increased level of systematic error. More details on his slides can be found [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/3350_dilution_talk.pdf here].
−	==5/13/2015==	+	==2/22/2017==
−	Present: JP, Chao, Min, Jie, Melissa<br>	+	Present: Ryan, Toby, David, Jie, JP<br>
−	By Phone: Pengjia, Ryan, Toby, Karl<br>	+
−	'''General Discussion:'''	+	'''Feature Presentations :'''
−	*Jie posted a draft of a technote on radiation effects in the g2psim package [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_05_13_simu_rad_technotes/radiation_simulation_technotes.pdf here].	+	No feature presentations this week. Everyone is planning on presenting next week.
−	*Toby posted a draft of a technote on dilution analysis [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/dilutionnote.pdf here].	+	==2/15/2017==
		+	Present: Ryan, Toby, David, Jie, JP<br>
−	'''Feature Presentations:'''	+	'''Feature Presentations :'''
−	*Melissa	+	*Jie:
−	**Looking into packing fraction runs for the 1.1 GeV setting, taken with the short ammonia cell.<br>She doubled checked the normalization constants used to calculate the yields and didn't find <br>anything strange.  She also looked at the s1 and Cherenkov channels for each of the four runs, <br>and found some small differences, but this is probably due to the fact that the runs were taken <br>at significantly different beam currents.  Two of the runs (5197,5198) were taken with a beam <br>current of 20nA (compared to 40-50nA that the other runs were taken at), which means the BPMs <br>are not reliable for these runs, so the beam position may be significantly different for these <br>runs.  It's possible there is some effect due to the high rate with a beam current of 40-50 nA <br>that is not being accounted for. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_05_13.pdf here].	+	Showed an update the BPM calibration. There was some discussion on the base assumptions Jie is making in removing potential position dependence on some calibrations constants (b-/b+). More details on his slides can be found [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2017_0214_plots/yields_update_20170215.pdf here].
		+	'''General Discussion :'''
−	==5/6/2015==	+	*Toby:
		+	Updated target polarizations are available now.
−	Present: Chao, Min, Jie, Melissa<br>	+	*Ryan:
−	By Phone: Pengjia, Ryan, Ellie<br>	+	HERMES publication from 2013 of new BC Sum Rule calculation at Q2 = 5 GeV2. Data is consistent with 0 but with large error bars.
		+	==2/8/2017==
		+
		+	Present: Ryan, Toby, David Karl, Jie, JP, Chao, Ellie<br>
		+
		+	'''Feature Presentations :'''
		+
		+	*Ryan:
		+	Showed the final systematics for the inelastic and elastic RC's. The end result is 2-3% for the elastic tail and 3-5% for the inelastic RCs. More details on his slides can be found [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_020817.pdf here].
		+
		+	'''General Discussion :'''
		+
		+	*Toby:
		+	Updating his systematic uncertainty on the target polarization analysis.
		+
		+	==2/1/2017==
		+
		+	Present: Ryan, Toby, David Karl, Jie, JP, Chao, Ellie<br>
		+
		+	'''Feature Presentations :'''
		+
		+	*Jie:
		+	Gave an update on the BPM analysis. Still have trouble solving the position jumps. More details on his slides can be found [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/20170201/yields_update_20170201.pdf here].
		+
		+	*Ryan:
		+	Showed the outline of the g2p radiative corrections procedure, including the polarized elastic tail and RADCOR and POLRAD formulations of the inelastic RCs. Also presented systematics for the unfolding procedure. He will next finalize the theory systematics for the RCs. More details on his slides can be found [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_012517.pdf here].
		+
		+	*Chao:
		+	Gave an update on the acceptance study. He showed that at the longitudinal setting the shift from 0 in the theta_tg histogram is caused by the target field. The effect is more pronounced at transverse settings. More details on his slides can be found [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/weekly/Chao_WeeklyMeeting_20170201.pdf here].
		+
		+	'''General Discussion :'''
		+
		+	*Toby:
		+	g2p dilutions are now available on the [https://hallaweb.jlab.org/wiki/index.php/G2p_dilutions wiki].
		+
		+	==1/18/2017==
		+
		+	Present: Ryan, Toby, Karl, Jie, JP, Chao, Ellie<br>
		+
		+	'''Feature Presentations :'''
		+
		+	*Jie:
		+	Hoping for a May graduation with his thesis split between three topics (g2p is one). Point was made that Jie must finish his BPM study before graduation because at this point he is the only one that can do it. More details on his slides can be found [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2017_0118_graduation_plan.pdf here].
		+
		+	*Toby:
		+	Hoping for a May graduation with a close-to-final g2 his goal for his thesis. Finishing up the dilution analysis for 3.3 GeV 5T. More details on his slides can be found [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/timeline_update_011817.pdf here].
		+
		+	*Ryan:
		+	Hoping for a June-August graduation with a close-to-final g2/hyperfine point his goal for his thesis. Finishing up the g2p radiative corrections procedure setup. More details on his slides can be found [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_011817.pdf here].
		+
		+	*Chao:
		+	Gave an update on the acceptance study. He is still having a hard time matching the simulation to data. More details on his slides can be found [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/weekly/Chao_WeeklyMeeting_20170118.pdf here].
		+
		+	'''General Discussion :'''
		+
		+	*Karl:
		+	is looking into the EG1b data for our highest Q2 settings as the parallel component for g2.
		+
		+	==1/11/2017==
		+
		+	Present: Ryan, Toby, Karl, Jie, David, Chao<br>
		+
		+	'''Feature Presentations :'''
		+
		+	*Ryan:
		+	Showed the effect a 0.3 degree scattering angle difference between HRSs would have on the data. Calculated this difference using models and then compared the data to it. The data is consistent with a straight line fit at 0, so the statistics of g2p are not sufficient to make a definitive statement. Also showed a calculation for the uncertainty in the out-of-plane polarization angle using a psuedo Monte-Carlo method. The uncertainty is around 1%. Details of his slides can be found [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_011117.pdf here].
		+
		+	==1/04/2017==
		+
		+	Present: Ryan, Toby, Karl JP, Jie,<br>
		+
		+	'''Feature Presentations :'''
		+
		+	*Ryan:
		+	Showed an update on the comparison between the LHRS and RHRS asymmetries for 2.2GeV 5T transverse. Using course 70 MeV bins and cutting out runs with large livetime and charge asymmetry he was able to get good agreement between the two spectrometers. The agreement is independent of the out-of-plane polarization angle correction. There is some question about the effect of the minor difference in the scattering angle between HRS's and the asymmetry. He will present on this difference at the next meeting. More details on his slides can be found [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_010417.pdf here].
		+
		+	*Jie:
		+	Still looking into the BPM calibrations and the source of the BPM position jumps that don't see a corresponding yield change. He hopes to have this analysis wrapped up by the end of January. More details on his slides can be found [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2017_0103_plots/yields_update_20170104.pdf here].
		+
		+	*Other news:
		+	At the 1/18/2017 weekly meeting we're planning on having a discussion on the analysis path forward. The primary focus on this discussion will be the experimental cross sections.
		+
		+	==12/21/2016==
		+
		+	Present: Ryan, Toby, Karl, Vince, JP, Jie, Chao<br>
		+
		+	'''Feature Presentations :'''
		+
		+	*Toby:
		+	Showed an update on the packing fraction analysis with a new method that is similar to his dilution calculation. This method gives a lower uncertainty than his elastic fit method. His two methods agree within the uncertainties for almost all of the settings. He will check the few kinematic settings where this isn't true and also try to pin down the systematic error from using the Bosted model to scale C12 to N14. More details on his slides can be found [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/pf_talk_122016.pdf here].
		+
		+	*Other news:
		+	Vince's last day at g2p meetings. Good luck at your new job Vince!
		+
		+	==12/14/2016==
		+
		+	Present: Ryan, Toby, Karl, Vince, JP, Jie, Chao<br>
	'''Feature Presentations:'''		'''Feature Presentations:'''
		+
		+	*Jie:
		+	Showed a status update on the BPM calibration procedure. More details can be found in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2016_11_10_plots/yields_update_20161214.pdf here].
		+
		+	*Chao:
		+	Still having trouble matching the width of the simulation peaks to peaks from data. Even getting rid of all apertures did not sufficiently widen the simulation peak. He is continuing to look into it. More details can be found [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2016_11_10_plots/yields_update_20161214.pdf here].
		+
		+	==12/07/2016==
		+
		+	Present: Ryan, Toby, Karl, Vince, JP, Jie, Alexandre<br>
		+
		+	Verbal Updates:
		+
		+	*Toby
		+	Working on getting his dilution code back up and running
		+
		+	*Ryan
		+	Working on asymmetry comparisons between the LHRS/RHRS at 2.2 GeV 5T Transverse.
		+
		+	*Jie
		+	Talking with Pengjia still about the BPM calculation procedure. Will give an in-depth update on the status of the BPM analysis at the next meeting.
		+
		+	==11/30/2016==
		+
		+	Present: Ryan, Toby, Karl, Ellie, JP, Jie, Kalyan, Alexandre, Vince, Jixie, Chao <br>
		+
		+	'''Feature Presentations'''
		+
		+	*Ryan
		+	Showed an update on the out-of-plane polarization angle calculation. The calculation agrees with Chao's result but still seems too large (40 - 65 degrees). Chao is working on confirming the results. Details of his slides can be found [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_113016.pdf here].
		+
		+	*Toby
		+	Showed an update on the packing fraction analysis. He presented final values for all settings except for 1.1 GeV 2.5 T. The difficulty at this setting is that the quasi-elastic peak is barely separable from the elastic peak so he is unsure of how to fit it. This is also a problem at the other 2.5 T settings and is manifest in the larger systematic uncertainties. Details of his slides can be found [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/pf_talk_113016.pdf here].
		+
		+	Verbal Updates:
	*Chao		*Chao
−	**Gave a status update on optics analysis.  He found that using the 2.2 GeV 5T longitudinal matrix <br>to replay the 1.7 GeV 2.5T transverse data resulted in an overall offset.  Because of this, it is <br>useful to do a full check of the relation between the reconstructed kinematics and the beam position. <br>If there is a correlation between the beam position and reconstructed kinematics, a linear fit will <br>be used to determine the correction.  The fitting result for &phi; for the two different settings is added <br>directly to the first order matrix element P0000 (constant term).  These matrices will be used to <br>replay the two data sets, and then the fitting procedure can be applied to improve higher order terms. <br>Next he will work on checking other energy settings.  More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150506/Chao_WeeklyMeeting_05062015.pdf here].	+	working on out-of-plane polarization angle calculation and will also confirm the proton elastic simulation results for Toby.
−	*Min	+	*Jie
−	**Showed an updated on focal plane matching.  For the 2.2 GeV, 0T setting with the "good" septum <br>(484816), the data and simulation match well at the focal plane.  However, data from the same setting <br>but with the target field at 2.5T do not match as well. She tried adjusting the beam position to find <br>a better match, but the correction needed was larger than the uncertainty on the beam position, so <br>JP suggested looking at the discrepancy starting from the central hole. By adjusting the beam position <br>and dipole field, she was able to match data from the central sieve hole to simulation results, within <br>uncertainties.  Next she will work on fitting the other sieve holes to match the data.  More details <br>can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/05062015/05062015.pdf here].	+	Talking with Pengjia still about the BPM calculation procedure.
		+	==11/23/2016==
−	==4/29/2015==	+	Present: Ryan, Karl, JP, Jie, Kalyan, Alexandre <br>
−	Present: JP, Chao, Min, Jie, Melissa<br>	+	*Jie
−	By Phone: Alex, Pengjia, Toby, Ryan, Ellie, Karl<br>	+	Discussed BPM calibration method
		+	*Ryan
		+	Working on calculating the out-of-plane polarization angle, with help from Chao. Hoping to confirm method with Chao and present something soon.
−	'''Feature Presentations:'''	+	==11/16/2016==
−	*Pengjia	+	Present: Ryan, Toby, Karl,Chao, Jie, Vince, Alexandre <br>
−	**Looked at the effect of different raster cuts on the asymmetry.  He looked at the 2.2 GeV 5T <br>settings, both longitudinal and transverse configurations.  First, he placed a cut on the center <br>of the raster (50% of total radius), which didn't have a large effect on the asymmetry.  He also <br>looked at the effect of splitting the beam spot into 4 quadrants; for some asymmetries there was <br>a considerable difference between the quadrants.  He also found that the yield is larger on the <br>left side of the beam spot.  More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/04282015/Asymmetries%20for%20different%20raster%20cut.pdf here].	+
−	*Melissa	+	'''Feature Presentations'''
−	**Showed the results of packing fraction analysis for the 1.1 GeV setting.  There is some <br>discrepancy in the yields for some materials, and the ratio of the rate/current is not consistent <br>in some cases.  She showed the effect of applying acceptance and PID cuts to each run; the <br>makes the largest impact is the cut on single track events, which cuts out ~50% of the total <br>events in some cases.  She will continue trying to figure out the cause of the variance in the<br>yields. More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_04_29.pdf here].	+
		+	*Jie
		+	Showed an update on the BPM calibration procedure. His correlation method for calculating the pedestals improves the uncertainty but does not affect the position reconstruction. In the calibration procedure there is an offset term that as large variations between calibration points. Pengjia fit this constant for current dependence but it is also possible it might have some positional dependence. Jie is going to talk with Pengjia about this. More details on his slides can be found [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2016_11_10_plots/yields_update_20161116.pdf here].
−	==4/22/2015==	+	Verbal Updates:
−	Present: JP, Chao, Min, Jie, Melissa<br>	+	*Toby is working on finalizing the uncertainties for the packing fraction analysis and is running into some issues with g2psim.
−	By Phone: Toby, Ryan, Ellie, Karl, Vince<br>	+
		+	*Ryan is working on calculating the out-of-plane polarization angle, with help from Chao.
−	'''Feature Presentations:'''	+	==11/02/2016==
		+
		+	Present: Ryan, Toby, Karl, JP, Vince, Alexandre <br>
		+
		+	'''Feature Presentations'''
		+
		+	*Ryan
		+	Showed a brief update on calculating the out-of-plane angle correction to the perpendicular polarized cross sections. He will talk to Chao about how to make this calculation using the reconstructed variables in the replayed ROOT files.  More details on his slides can be found [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_110116.pdf here].
		+
		+	*Toby
		+	Showed a slide on the yield spectra for the elastic runs in PF analysis at all kinematic settings. The nitrogen and helium peaks are only clearly visible at the 2.2 GeV 5T transverse setting, so he will need to adjust his fitting routine to account for this at the other settings.  More details on his slides can be found [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/elastic_allsettings.pdf here].
		+
		+	==10/26/2016==
		+
		+	Present: Ryan, Toby, Karl, Jie, JP, Chao, Ellie, Vince, Jixie <br>
		+
		+	'''Feature Presentations'''
		+
		+	*Ryan
		+	Showed an update on the polarized radiative corrections using POLRAD at the g2p kinematics (non-constant scattering angle). He showed that using the same angle fit for all the input spectra (as opposed to individual fits representing measured data) the systematic error was similar to that of data taken at a constant scattering angle. For this study he used the MAID 2007 model. He recommends using models for the RC'ing of g2p data but those models could be tuned and checked using measured data. More details on his slides can be found [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_102616.pdf here].
		+
		+	Verbal Updates:
	*Chao		*Chao
−	**Gave an update on optics analysis.  Using data from the single foil target does not provide enough <br>constraints for optics analysis, but there are two other methods to additionally constrain the data. <br>One way is to look at the relation between the kinematics and beam position for beam position scan <br>runs, and the other way is to include data from the aluminum window into the fitting procedure to <br>directly correct the reconstruction matrix. The second method is what was tested for this week. To <br>improve the fitting routine, he first fits the k=0 matrix elements without the Aluminum window data, <br>then fixes the other matrix elements and fits the k=l matrix elements after adding in the aluminum <br>data. He found that he couldn't get a good fit using the aluminum window data, even if only the y-fp <br>matrix elements are allowed to vary.  JP commented that, since y and &phi; are coupled, they cannot be <br>fit separately.  It's possible that a higher order polynomial is necessary for the fit. More details <br>can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150422/Chao_WeeklyMeeting_04222015.pdf here].	+	Working on the optics and acceptance simulation and tuning the simulation aperatures. Showed a short slide with better agreement between data and simulation. Still working on improving this.
		+
		+	*Jie
		+	Working on the BPM position calibration procedure.
		+
		+	==10/19/2016==
		+
		+	Present: Ryan, Toby, Karl, Jie, JP, Chao, Ellie, Vince, Jixie <br>
		+
		+	'''Feature Presentations'''
	*Toby		*Toby
−	**Put together a summary of the data quality checks on the yields (detailed [https://hallaweb.jlab.org/wiki/index.php/G2p_data_quality here]), including the <br>number of useable runs and percentage of useable statistics in each kinematic setting. Overall, the 5T <br>settings look the best, with the exception of the 3.3 GeV setting, which has several settings with yield <br>drifts that appear to be unrelated to beam position changes.  Karl suggested checking the stability of the <br>dipole for settings with bad runs.  More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/qualitychecktalk.pdf here].	+	Showed an update on his method for calculating the packing fraction, along with his estimate for the systematic uncertainty. He's hoping to finalize the results for the 5.0 T settings within the next few weeks.  More details on his slides can be found [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/pf_talk_101816.pdf here]. There was some discussion that his uncertainty of ~8% in the fitting method is overestimated as described in the slides, so hopefully the systematic uncertainty is at the 10% level, maximum.
		+	Verbal Updates:
−	'''General Discussion:'''	+	*Chao
−	*Pengjia posted a draft of a technote on beam charge measurements [http://hallaweb.jlab.org/experiment/g2p/technotes/bcm_technote.pdf here], and would appreciate feedback.	+	Working on the optics and acceptance simulation and tuning the simulation aperatures.
		+	*Jie
		+	Working on the BPM position calibration procedure. Still trying to fully understand Pengjia's method.
−	==4/15/2015==	+	*Ryan
		+	Working on setting up inelastic radiative corrections procedure for changing angle of g2p.
−	Present: Jixie, Min, Chao, JP, Jie, Melissa<br>	+	==10/12/2016==
−	By Phone: Vince, Pengjia, Toby, Ryan, Ellie, Karl<br>	+
		+	Present: Ryan, Toby, Karl, Jie, JP, Chao <br>
−	'''Feature Presentations:'''	+	'''Feature Presentations'''
	*Jie		*Jie
−	**Gave a simulation update, specifically looking at acceptance and yields. Last time, he used a point <br>beam a moved the position from 0-10 in x and y to see the effect on the acceptance and the yields.  This <br>time, he looked at the acceptance at each endplane using a point beam at (0,0) and (-10,0). One big <br>difference is the number of events blocked by the Q1 exit for these two beam positions.  He went step by <br>step through the simulation to compare the number of events that reach each enplane to the number of <br>events that pass through the plane.  He found that the shift of the beam position by 1cm caused a drop of <br>~20% in the acceptance.  JP and Vince commented that this drop seems too large.  It's possible the septum <br>is also playing a role in the decreased acceptance, not just Q1.  More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_04_15_acc/2015_04_15_Simulation_update.pdf here]	+	Showed final results for the BPM pedestal uncertainty using his new correlation method for the 2.2 GeV 5T transverse setting. The uncertainties are about a factor of 3-4 better than previous and are approx. 1mm and 1mrad at the target. He is moving on to finishing this study at other settings and also looking into the BPM calibration procedure and beam position jumps.  More details on his slides can be found [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2016_10_10_plots/yields_update_20161010.pdf here].
−	*Melissa	+	Verbal Updates:
−	**Gave an update on packing fraction analysis. She extracted pf values for numerous elastic runs for <br>several settings.  For settings where there is a drift in the yields, the pf also varies.  The most <br>variation is seen in the 2.2 GeV, 2.5T setting.  The raster size was changed part way through this <br>setting, so it may not be possible to compare runs with different rater sizes without first correcting <br>for this difference. She will continue working on trying to understand the discrepancies in the yields, <br>and finish extracting the values for the 1.1 GeV setting, for the regular and short ammonia cells. More <br>details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_04_15.pdf here].	+
		+	*Chao
		+	Working on the optics and acceptance simulation. Believes that the previous mismatch he showed with data and simulation at bigger angular acceptance was due to the simulation aperatures blocking more events than seen in the data. Current size estimates of the aperatures is from a combination of g2p survey and historical Hall A information.
		+
		+	*Toby
		+	Working on packing fraction results and updating the systematic error analysis. Hoping to finalize shortly.
	*Ryan		*Ryan
−	**Gave an update on radiative corrections. He took a closer look at the systematic error on the <br>inelastic radiative corrections, which are different now that he has removed the interpolation from the <br>unfolding procedure.  He replaced the interpolation with a direct call to the Bosted Model. Comparing <br>the two methods, he found that they are consistent with each other.  The interpolation will be the <br>largest contribution to the systematic error. He also wanted to test if there was a faster way to <br>radiate a model. There are two ways to do the integration within the Stein equation, Romberg or Simpson <br>integration. The Romberg method is more accurate, but takes longer.  The results from using both methods <br>to radiation the Bosted model are nearly identical, but the Simpson method is orders of magnitude faster, <br>particularly for finer &nu; binning.  Next he will work on setting up polarized radiative corrections. <br>More details can be seen in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_041515.pdf here].	+	Working on setting up inelastic radiative corrections procedure for changing angle of g2p.
		+
		+	==10/05/2016==
		+
		+	Present: Ryan, Toby, Karl, Ellie, Jie, JP, Jixie <br>
		+
		+	'''Feature Presentations'''
		+
		+	*Ryan
		+	Showed the reconstructed angle for a loose cut on all of the LHRS g2p production data. The fit is a combination of a linear and exponential fit; this form is suggested from a Jixie ELOG post. For the most part there is good agreement with the data to the fit, and outliers from the fit is a potential criteria for selection of good runs. He used these fits to mimic g2p data and test RC procedures on data at different angles. He found that he could do RC's with small systematic error if he used the same fit for all input spectra. This is not the case for g2p data, so he's working on improving the method.  More details on his slides can be found [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_100516.pdf here].
		+
		+	Verbal Updates:
		+
		+	*Jie
		+	Working on the BPM pedestal issue. He's now considering correlations between all channels in the BPM pedestals. This slightly increases his uncertainty but it is still smaller than Pengjia's result and helps alleviate the triple peak issue.
	*Toby		*Toby
−	**Gave an updated on dilution analysis.  He showed a central fit to the scattering angle compared to the <br>model prediction done by Jixie.  This is used to scale the angle between different run types, such as <br>scaling carbon dilution to nitrogen production.  Since the optics isn't complete yet, this scattering angle <br>is just a place holder until we better understand the scattering angle.  At large &nu;, the dilution factor <br>(and packing fraction) starts to drop off, which he thought could be due to a problem with the scattering <br>angle correction.  JP commented that this might not be the case, since this is a ratio, but due to the fact <br>that at low Q squared the DIS cross section is small.  This will probably result in a large statistical <br>uncertainty on the dilution factor.  Next Toby will extract the dilution factor for the 1.1 GeV and 1.7 GeV <br>settings, and finish writing a technote on this analysis.  More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/diltalk_041515.pdf here].	+	Working on packing fraction results and updating the simulation calculations needed for the cross section ratio input.
		+	*SPIN 2016
		+	Chi-PT calculations of the polarizabilities are still bad. NEED DATA!
−	==4/8/2015==	+	==9/21/2016==
−	Present: Chao, Min Kalyan, Jie, Melissa<br>	+	Present: Ryan, Toby, Karl, Chao, Jie, JP, Jixie, Kalyan, Vince <br>
−	By Phone: Alex, Vince, Toby, Ryan, Karl, Ellie, Pengjia<br>	+
		+	'''Feature Presentations'''
−	'''Feature Presentations:'''	+	*Jie
		+	Showed an update on the BPM pedestal calculation. Found a correlation between the pedestals on BPM channels. By using a rotated coordinate system, he can decouple the correlation. This allows for a reduced uncertainty in the BPM pedestal uncertainty contribution to the BPM calculation. More details on his slides can be found [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2016_09_21_plots/yields_update_20160921_new.pdf here]. Will work on finalizing the updating uncertainty calculations and continue with checking the BPM calibration.
−	*Chao	+	*Ryan
−	**Gave an update on optics analysis.  Previously he showed that there is an issue with the horizontal beam <br>position changing the dp reconstruction. Since there aren't enough constraints to do the reconstruction, it <br>is necessary to do a full check of the relations between the beam position and the reconstructed kinematics. <br>He looked at delta scan runs and beam position scans to check the correlation between the beam position <br> and reconstructed variables.  To correct for these effects, he used a linear fit to determine a correction factor<br>for &theta;, &phi; and dp.  To test this method he used a production run, and placed cuts on the raster pattern in <br>different areas around the center of the beam spot. While the "old" reconstructed dp variable shifted based <br>on the location of the cut, the "corrected" dp variable was stable.  Next he will work on applying this method <br>to other settings.  More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150408/Chao_WeeklyMeeting_04082015.pdf here].	+	Showed the reconstructed angles for three different asymmetry cuts for both the transverse longitudinal asymmetries. There is a difference between the hot-spot angle in the transverse asymmetry. The RHRS accepts smaller angles in the transverse configuration but this cannot account for the difference in the HRS asymmetries between L/R. More details on his slides can be found [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_092116.pdf here]. He will try different cuts on different variables to try and find a set that gives agreement between the LHRS/RHRS.
		+	**NO MEETING NEXT WEEK BECAUSE OF SPIN 2016
−	==4/1/2015==	+	==9/14/2016==
−	Present: Min, Chao, Kalyan, JP, Jie, Jixie, Melissa<br>	+	Present: Ryan, Toby, Ellie, Karl, David, Chao, Jie, JP, Jixie, Kalyan, Vince <br>
−	By Phone: Ryan, Toby, Pengjia, Vince, Alex<br>	+
		+	'''Feature Presentations'''
−	'''Feature Presentations:'''	+	*David
		+	Showed a statistical analysis between the LHRS and RHRS asymmetries for the 2.2GeV 5T transverse/longitudinal data. Concluded that for long. data the two spectrometers are statistically measuring the same thing. Further work still needs to be done on for the transverse asymmetries. His slides can be found [https://userweb.jlab.org/~rbziel/Weekly_Meetings/chi2slides_2.pdf here].
−	*Melissa	+	*Toby
−	**Gave an update on packing fraction analysis. She started extracting the pf for the 2.5T settings, but the biggest <br>lingering issue is the discrepancy seen in the yields for elastic pf/production runs. Several suggestions were made <br>to check for a possible problem, such as the septum field drifting over time, looking at the raster pattern, and <br>checking the scalar rates and normalization values (specifically the charge). More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_04_01.pdf here].	+	Showed an updated packing fraction calculation where he replaces fits to the quasi-elastic and quasi-elastic contamination with the Bosted model. His packing fractions are in much better agreement with this method and the consensus is that the fit method was driving the large differences previously seen. He was given suggestions on trying to better quantify the quasi-elastic contamination, including using other models and separating the kinematic regions using acceptance cuts. More details can be found in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/pf_update_091416.pdf here].
		+
		+	*Jie
		+	While on the schedule, he will present next week.
		+
		+	==9/7/2016==
		+
		+	Present: Ryan, Toby, Ellie, Karl,  Chao, Jie, JP <br>
		+
		+	'''Feature Presentations'''
		+
		+	*Chao
		+	Gave an update on the acceptance study of the 5T longitudinal setting. He's currently working on tuning the resolution of the simulation package. He finds that he can match the width of the elastic peak for a small range in theta and phi target but as he increases that range his simulation produces too narrow of a spectra. He is working on fixing this issue. His slides can be found [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20160907/Chao_WeeklyMeeting_09072016.pdf here].
	*Ryan		*Ryan
−	**Gave an update on automated model tuning for determining the carbon/nitrogen cross section ratio.  Previously, the <br>tune was optimized in the order dip-region, inelastic, quasielastic. For this time he swapped the order to inelastic,<br>quasielastic, dip-region.  The final overall tune represents an average of each settings parameters. He found that <br>the best average reduced chi-squared was found after the second iteration, and the fit is good to within 10%.  Next <br>he will look at saGDH nitrogen data, but is waiting on updated cross sections from Vince. More details can be seen <br>in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_040115.pdf here].	+	Showed a comparison between the 5T longitudinal asymmetries using different acceptance cuts. He demonstrated that within our statistical error bars we do not need to make a bin-centering correction to the asymmetries for the longitudinal setting. He also tried to see if a model accurately described the asymmetry change with angle but was not successful. More details can be found in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_090716.pdf here].
−	*Min	+	==8/31/2016==
−	**Gave an update on acceptance studies.  Last time she compared the data from a delta scan in the 2.2 GeV, 2.5T <br>setting (with good septum) with simulation results and found some differences.  This time she adjusted the beam <br>position in the simulation to match the data, which was quite different from the original beam position.  Kalyan <br>suggested looking at just the center hole of the sieve slit to determine the offset.  It seems the offset is seen <br>in the data, but the simulation shifts the events in the opposite direction.  Min/Chao have a plan to check each <br>part of the simulation, and Pengjia will check the beam position calibration for this setting.  More details can <br>be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/04012015/04012015.pdf here].	+
		+	Present: Ryan, Toby, Ellie, Karl, Jixie, Vince, Jie, Alexandre, JP <br>
		+
		+	'''Feature Presentations'''
	*Jie		*Jie
−	**Gave a simulation update, specifically checking the target center compared to the position given by the BPM at <br>the target. His goal was to test if the target was centered, whether the BPM could have an offset? Or if the <br>target was centered and the BPM position was correct, could the raster size be scaled incorrectly? Looking at <br>several runs he saw a shift of 1cm in the target center. However, as the runs were at different energy settings, <br>the beam position wouldn't necessarily be the same.  Kalyan suggested looking at the carbon hole runs nearest to <br>these runs as a check.  For next time he will focus on simulating the shifts we see in the yields. More details <br>can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_03_31_bpmpos/2015_03_31_Simulation_update.pdf here].	+	Gave an update on the BPM pedestal analysis. He showed results from the pedestal analysis of beam trip runs for both the Happex DAQ and HRS DAQ. HRS DAQ has cleaner pedestals but the HRS DAQ is less precise. The pedestal shift seen in the HAPPEX DAQ is continuos with time. He will continue to look at the BPM calibration procedure and try and quantify the effect the pedestals have on the BPM uncertainty. More details can be found in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2016_08_28_plots_eps/yields_update_20160831.pdf here].
		+	Verbal Updates:
		+	*Ryan
		+	Continuing to look at HRS asymmetry angle dependence
−	==3/25/2015==	+	==8/24/2016==
−	Present: Jie, Min, Vince, JP, Chao<br>	+	Present: Ryan, Toby, Ellie, Chao, Vince, Jie, Alexandre, JP <br>
−	By Phone: Ryan, Karl, Toby, Alexandre, Pengjia <br>	+
		+	'''Feature Presentations'''
−	'''Feature Presentations:'''	+	*Toby
		+	Showed an update on the packing fraction analysis. He has been able to successfully fit the two elastic peaks (N2 and He4) and quasi-elastic peak to produce packing fraction results. He also presented an alternative calculation to the packing fraction, just using the helium peak from production and a dummy/empty run. His two methods agree at the ~10% level but differ greatly from what Melissa showed previously. Toby will continue to look at his fits and see if there is room for improvement there because there is some fit dependence on the result. One suggestion was to fit the simpler dummy run He4 elastic peak and use those fit parameters in the production runs. More details can be found in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/pf_update.pdf here].
		+
		+	Verbal Updates:
		+	*Ryan
		+	Continuing to look at HRS asymmetry angle dependence
	*Jie		*Jie
−	**Gave an update on simulation package. The elastic radiation tail include soft photon contribution is compared with <br> the result from the predication calculated using Mo/Tsai. The tail matches at ΔE~6MeV. He also looked at the effect <br>of the beam position on the acceptance. The simulation covers the full angle acceptance to test the aperture cut <br>in the SNAKE model. The simulation shows that φ acceptance has large correlation with the horizontal beam position. <br>JP suggests the aperture setting in the model may be not sufficient to represent the real situation. Chao suggests <br>that to use the simulation to determine which aperture stops most particles. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_03_23_rad_effects/2015_03_25_Simulation_updae.pdf here].	+	Working on understanding Pengjia's BPM code.
		+
		+	==8/17/2016==
		+
		+	Present: Ryan, Toby, Ellie, Chao,  Vince, Jie, Alexandre <br>
		+
		+	'''Feature Presentations'''
		+
		+	*Ryan
		+	Showed a comparison between asymmetries between LHRS and RHRS for the three 5T settings: 2.2 GeV long/trans and 3.3 trans. Overall there is good agreement between the HRS's, and the biggest disagreement is between the arms at the 2.2 GeV trans setting. Ryan will check that scattering angle dependence of the asymmetries next to see if this can improve the agreement. Currently the RHRS scattering angle reconstruction is not correct. Chao believes this is a coordinate system issue in his code. Slides can be found [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_081716.pdf here].
		+	Verbal Updates:
	*Chao		*Chao
−	**Gave an update on the optics calibration. As Jie points out before, the reconstructed dp does not agree with the <br>prediction very well when horizontal beam position changes. The beam position scan runs are used to fit a correction <br>to the dp reconstruction matrix. The correction could correct the dp reconstruction result for optics runs. However, the <br>reason of this correction is still not clear. After discussion, the suggestion is to add the correction back to the dp matrix <br>and redo the fit of higher order terms. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150325/Chao_WeeklyMeeting_03252015.pdf here].	+	Back at JLab for one year. First thing he will focus on is correcting the scattering angle reconstruction for the RHRS replay. After this he will move onto the acceptance study for the 5T longitudinal setting.
		+
		+	*Jie
		+	Working on understanding Pengjia's BPM code.
	*Toby		*Toby
−	**Gave an update on dilution study. He showed dilution results for all completed settings. The tech note of the dilution <br>study is in progress. He also mentioned an alternative way to calculate the packing fraction. The method only works in <br>DIS region but a 0th order polynomial fit at large ν can be used to find the packing fraction everywhere. All packing <br>fractions seem about 5-10% larger than typical values. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/pf_dil_talk.pdf here].	+	Working on updating the target polarizations for the HRS's. Found a bug in his code in converting UNIX times. Also developing two parallel methods to determine packing fraction, one using fits and another using simulation.
−	*Pengjia	+	==8/03/2016==
−	**Presented some preliminary results of asymmetry and yield for RHRS. He compared the right arm asymmetry and yield <br>with left arm for two kinematic settings. The asymmetry results agree quite well but the yields has some deviation for <br>the 2.2GeV, 5T longitudinal field setting, perhaps caused by acceptance effect. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/03252015/asym_lr.pdf here].	+
		+	Present: Ryan, Toby, Karl, Vince, Jie, Alexandre <br>
−	==3/18/2015==	+	No Presentations.
−	Present: Jixie, Chao, Jie, Min, Kalyan, JP, Melissa <br>	+	Verbal Updates:
−	By Phone: Ryan, Karl, Toby, Alexandre, Vince, Pengjia <br>	+
		+	*Jie
−	'''Feature Presentations:'''	+	Got code for BPM calibration from Pengjia. Still waiting on some further explanation from Pengjia on the code. He will focus on the 5T settings first in the calibration
−	*Melissa	+	*Toby
−	**Gave an update on packing fraction analysis.  For each setting, she tried to identify ammonia runs that could <br>be used for the analysis, ideally runs that were taken in close proximity to the dilution (dummy/empty) runs, or <br>at least where the beam position is similar.  In addition, the fitting routine (to understand the level of <br>contamination from the 2nd peak) was adjusted for each energy setting.  The 2.2 GeV, 5T settings (longitudinal <br>and transverse) have ammonia runs taken close in time to the runs to helium.  The 1.7 GeV setting has some <br>variation in the ammonia yields, but they are not too large.  The 1.2 GeV energy setting has significant variation<br>in the elastic yields; she will look more into these runs to see if there is an obvious reason for the variation. <br>She also showed the fit results for the different energy settings; JP suggested checking the hydrogen fit, as it <br>seems a bit wide.  More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_03_18.pdf here].	+	Working on the g2psim package and using it for calculating the packing fraction. Replayed RHRS 5T transverse data, and according to Chao it should have final optics.
	*Ryan		*Ryan
−	**Working on an automated model tune, which will be used to determine the ratio of carbon to nitrogen for dilution <br>analysis.  Last time, he showed an automated tune of the Bosted model, which assumed that the quasi-elastic and <br>inelastic channels are independent one another and can be optimized independently.  The caveat to this is that the <br>tune is only valid in the Q<sup>2</sup> range and for the target type of the input data.  For this time, he updated the<br>automated tune procedure to include an adjustment for the "dip" region.  The Bosted model parametrization of the <br> dip region is a Gaussian that is calculated as part of the inelastic channel.  Including the dip region improves the fit <br>to carbon data for each individual setting, however the overall fit it worse.  JP suggested that fitting the dip region <br> first may be the problem; Ryan will try to swapping the order of the fitting routine to see if it improves the fit. <br> More details can be seen in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_031715.pdf here].	+	Has a working model dilution code.
−	*Min
−	**Gave an update on her acceptance study.  To improve the simulation, she included data from the windows into the <br>calibration and updated the results for the delta scan runs.  This new function was applied to both horizontal and <br>vertical beam scan runs.  This improved the agreement between the data and simulation, especially for the horizontal <br>beam scan run.  She also looked at beam scan runs with the target field on, this time adding an additional constant <br>on y and &phi;.  For the fit of the focal plane, JP cautioned not to use too high-order of a fit, as it can become <br>non-physical.  For next time, she will adjust the fitting function.  More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/03182015/03182015.pdf here].
−	*Pengjia	+	==7/27/2016==
−	**Looked at the effect of raster cuts on the yield.  He looked at several kinematic settings with consistent yields <br>and a applied a raster cut with a diameter of 6mm.  He found that applying the raster cut had a negative effect; <br>meaning the spread in the yields became larger after the cut was applied.  He also showed the x and y positions at <br>BPM A and B for each set of runs.  In some cases, the x-position at BPMA is stable, but it varies at BPMB, which <br>could be the source of the variation in the calculated scattering angle.  It may be more useful to do a relative <br>study, (similar to what Jie has shown previously) for individual runs than trying to compare separate runs.  More <br>details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/03112015/Raster_Cut_201503011.pdf here].	+
		+	Present: Ryan, Toby, Jie, Vince, Kalyan,  JP, Karl <br>
−	==3/11/2015==	+	'''Feature Presentations:'''
−	Present: Chao, Jie, Min, JP, Melissa<br>	+	*Jie
−	By Phone: Vince, Toby, Ryan, Karl, Alexandre<br>	+	Working on trying separate two peaks in the BPM pedestal runs.  It does not appear that the two peaks can be filtered based upon the frequency using an FFT. Moving forward he will check how the double peaks affect BPM calibration uncertainty and check the BPM calibration procedure. More details can be found in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2016_0723_plots/yields_update_20160727.pdf here]
		+	*Ryan
		+	Presented raw asymmetries with three difference acceptance cuts to highlight the angle dependence on the asymmetry in the delta-region. Was able to produce a similar trend in models using scattering angles from the data. Going forward will try to find acceptance cuts that select similar numbers of events and see if the ratio between data points is the same as the ratio of model points to do a bin-centering type correction. More details can be found in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_072716.pdf here]
−	'''Feature Presentations:'''
−	*Jie	+	==7/20/2016==
−	**Working on updating the energy loss model in the simulation package.  Previously it was found that the energy loss <br>model in g2psim does not match the prediction calculated using the Mo/Tsai formulation. He found that the soft photon<br>contribution was missing.  This term could have a large contribution, up to 20%.  He also looked at the effect of <br>changing the scattering angle on the dp distribution.  Over an 80mrad change in the scattering angle, he saw only a <br>~0.16% change in the dp distribution.  He also looked at 5 different areas of the beam spot, to see how the dp changed <br>in that region.  The simulation results show no change in the dp distribution in the different regions, but the data <br>shows that the dp distribution shifts as you move around the beam spot. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_03_06_xs_ratio/2015_03_11_Simulation_updae.pdf here].	+
		+	Present: Ryan, Toby, Jie, Vince, Alexandre , Kalyan, Karl, Ellie  <br>
−	'''General Discussion:'''	+	Verbal Updates:
−	*Ryan sent around an abstract for the upcoming Chiral Dynamics workshop, comments are appreciated.	+
−	*JP sent around the latest version of Pengjia's BPM paper, feedback is appreciated.	+
		+	*Jie
		+	Looking into 2-peak pedestal issue for the BPMs. Checking to see if the two peaks are at different frequencies and can be separated. If they cannot then the 2-peak pedestals will increase the BPM reconstruction uncertainty at the target to ~3-4mm (from 1-2mm) for runs with the double peak. Previously Pengjia did not consider any RMS value above 2000 in his analysis.
		+
		+	*Toby
		+	Still working on getting the g2p simulation package to match g2p data. Able to now produce elastic peaks in the correct locations to match data. Requesting that someone familiar with g2psim make a post on the wiki detailing the variables in the output of the simulation root tree because they are not straight-forward to understand.
		+
		+	*Ryan
		+	Completed setting up a python version of the radiated model code. Uses MAID/Hall B for the polarized and Bosted for the unpolarized. Does the unpolarized and polarized elastic tail but only uses RADCOR for the inelastic radiating.
−	==3/4/2015==
−	Present: Chao, Jie, Min, JP, Melissa<br>	+	==7/13/2016==
−	By Phone: Vince, Toby, Ryan, Karl, Pengjia<br>	+
		+	Present: Ryan, Toby, Jie, Vince, Alexandre ,  JP, Karl, Ellie  <br>
	'''Feature Presentations:'''		'''Feature Presentations:'''
		+	*Jie
		+	Showed a comparison between the BPM pedestals calculated during dedicated pedestal runs and during beam trips. The two methods agree, so Jie is moving forward with the beam trip method to fill in gaps for BPM pedestal calculations. His next step is to move onto checking the BPM calibration. More details can be found in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2016_0710_plots/yields_update_20160713.pdf here]
		+
		+	Verbal Updates:
	*Toby		*Toby
−	**Gave an update on dilution analysis.  He finished tuning the Bosted model in order to obtain cross section ratios used <br>for radiation length matching for dilution runs (for example, scaling a helium run to match the radiation length of a carbon <br> run).  He showed the calculated background over the full kinematic range for the 2.2 GeV, 5T, Transverse setting.  The <br>dilution factor can then be extracted using the ratio of the background yield to the total yield. Eventually he will be able <br>to update the dilution factor using material specific packing fraction values (when they are ready), and an improved tune <br>of the XS model.  Next he will work on other settings and compiling a technote.  More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/diltalk_030415.pdf here].	+	Still working on getting the g2p simulation package to match g2p data. This will be used for calculating the packing fraction
	*Ryan		*Ryan
−	**Working on a method to automate model tuning for the QFS and Bosted models.  For dilution analysis it is necessary <br>to scale carbon data as a replacement for nitrogen yields.  Since there is no nitrogen and carbon cross sections available <br>from the same experiment, it is necessary to use to model tune of saGDH data for nitrogen, and a model tune of data <br>from UVa archives for carbon.  Previously, this tuning was done "by hand", with a reduced &chi;<sup>2</sup> to determine the <br>quality of the fit.  A problem with this method is that it could result in inconsistent results for different people tuning the <br>same data set; an automated method could solve this problem.  JP commented that a possible problem with an automated <br>method is that the physics is simplified.  He showed results for tuning the Bosted model to carbon data, next he will work <br>on saGDH data, and then will repeat the procedure for the QFS model.  More details, including a description of the code <br>structure, can be seen in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_030415.pdf here].	+	Working on producing radiated models to compare to the g2p data.
−	*Melissa
−	**Gave an update on packing fraction analysis.  Previously, she described an update to her method to include cross section <br>input.  Elastic form factor models were used to determine the cross section ratio &sigma;N/&sigma;He.  To obtain radiated  cross sections<br>two methods were used.  First, using the g2psim energy loss model, and second, using the Mo/Tsai formalism to calculate <br>the correction to the elastic peak.  There is a discrepancy between these methods, specifically that the results suggest that <br>the correction is smaller than it should be.  This will have to be resolved to get an accurate value for the cross section ratio.  <br>She is also working on fitting the data for dilution and production runs for other energy settings to extract packing fraction <br>values for other materials.  More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Elastic/Elastic_03_04.pdf here].
−	*Min	+	==7/6/2016==
−	**Gave an update on her acceptance study.  Last time she found that the focal plane variables for production runs didn't <br>match well with the simulation.  Production runs have a rastered beam, as opposed to the point beam used in optics <br>calibration runs, so this effect must be corrected for.  For this week, she looked at events at the target window in the focal <br>plane, and used these events to improve the fitting at the virtual plane.  She also looked at events from the carbon foil at <br>the focal plane, and saw a reasonable match.  Next she will work on further improving the fitting and incorporating the <br>results into g2psim.  More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/03042015/03042015.pdf here].	+
		+	Present: Ryan, Jie, Kalyan,  JP, Karl, Ellie  <br>
−	==2/25/2015==	+	Verbal Updates:
−	Present: Chao, Jie, Min, JP, Melissa<br>	+	*Jie
−	By Phone: Toby, Ryan, Ellie, Pengjia<br>	+	Working on comparing pedestal values from dedicated pedestal runs and from beam-trip's. He's mostly found agreement and is working to settle the few outliers. After this he is moving onto to checking the BPM calibration.
		+
		+	*Ryan
		+	Working on setting up radiated models to compare with the radiated data asymmetries.
		+
		+
		+	==6/29/2016==
		+	Present: Ryan, Toby, Jie, Vince, Kalyan,  JP, Karl, Ellie  <br>
	'''Feature Presentations:'''		'''Feature Presentations:'''
	*Jie		*Jie
−	**Working on understanding the yield drifts due to changes in the beam position. He used beam position information <br>as input to the simulation, and applied loose acceptance cuts to determine the yield.  He looked at several momentum <br>settings that had a drift in yields >3% in the 1.7 and 1.1 GeV energy settings.  In general he found that the effect was <br>opposite of what is seen in the data. JP suggested doing the study independent of data, so as not to bias the results, <br>and to show the dependence of the yield on each parameter (x,y,&theta;,&phi;) individually. He also suggested checking to <br>make sure the acceptance effects are included properly, as it is difficult to get them to agree at the boundaries. Jie will <br>keep working on this, and will start working on the septum SNAKE model for the 403216 septum configuration. More <br>details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_02_24_yields/Simulation_update_2015_02_24.pdf here].	+	Gave an update on the BPM pedestal issues. In his slides he shows the pedestal histograms to demonstrate that the pedestal value is really shifting with time. Some pedestal's also exhibit a multi-peak structure, which ultimately will effect the uncertainty of the BPM calibration. He also showed the effect of using different BPM pedestal values for different runs and effects the BPM reconstruction. The resulting BPM position change is much larger than simulation would predict indicating that again that the BPM pedestal value is really changing with time. Going forward he will look to determine an accurate BPM uncertainty from the fluctuating pedestal values. More details on his slides can be seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2016_0627_plots/yields_update_20160629.pdf here].
−	*Pengjia	+	Verbal Updates:
−	**Trying to determine if applying a raster cut to the data will fix the spread in yields.  The difficulty is in determining <br>the total charge after this cut is applied.  To determine the charge, he used the calibrated charge info from both the <br>happex and fastbus, and applied the same raster cut to each.  He was then able to use the happex raster cut info to <br>get the charge from the happex bcm.  JP pointed out that, since the happex and fastbus aren't synchronized, this <br>method may only work if the beam is stable, so it is important to quantify an uncertainty on the charge.  He suggested <br>trying this method again with a much smaller raster cut, so that whatever effect this method will be magnified.  Pengjia <br>will first look at a setting where the yields are stable to see the effect of this cut, then will move on to settings that have <br>issues.  The raster cut library and testcode is available on the work disk, see his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/02252015/Position_Cut_20150225.pdf here] for more details.	+
−	*Chao	+	*Toby
−	**Posted the draft of a technote on target field mapping [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/technotes/Chao_TechNote_TargetField.pdf here]. Any comments would be appreciated!	+	Working on updating Melissa's packing fraction code to use simulation to match the quasi-elastic peak, instead of relying on fits because the packing fraction result is highly-sensitive to the fit parameters.
		+	*Ryan
		+	Working on raw asymmetries and comparing them with Toby to make sure they agree.
−	==2/18/2015==	+	*Vince
		+	Has updated ChiPT calculations that he will send out over the mailing list.
−	Present: Chao, Jie, Kalyan, Melissa<br>
−	By Phone: Vince, Ryan, Toby, Min<br>
		+	==6/22/2016==
		+
		+	Present: Alex, Ryan, Toby, Jie, Vince, Kalyan  <br>
	'''Feature Presentations:'''		'''Feature Presentations:'''
−	*Min	+	*Toby
−	**Gave an update on her acceptance study. She showed a comparison of simulation results with data from a production <br>run. As was suggested previously, she expanded the acceptance range when generating events. She found that the <br>focal plane variables still don't match very well. One possibility is that the production runs have a raster beam, but the <br>optics runs she had looked at previously used a point beam, so this effect needs to be corrected for somehow. More <br>details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/02182015/02182015.pdf here].	+	Received Melissa's packing fraction code. Found that there is now a difference in the nu histograms for the elastic runs when compared to what Melissa used in her analysis. Melissa's tech-note shows only a single elastic peak, but new root-files have both a elastic nitrogen and helium peak. The two peaks are separated by about 5 MeV at E0 = 2.2 GeV. The existence of an additional peak effects the applicability of Melissa's fitting routines to these new root-files. Toby will contact Melissa and see what she can provide. Slides are [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/elasticyield_talk.pdf here].
		+	Verbal Updates:
−	'''General Discussion:'''	+	*Jie
−	*Chao mentioned that a problem was found in the most recent BPM package, and it may have caused a problem <br>in the replay. Toby will discuss this with Pengjia offline.	+	Jie is still talking with Pengjia over the BPM pedestal issue. He hopes to have slides for next week's meeting.
		+	*Ryan
		+	Ed Folts confirmed the presence of helium bags in the septum bores and local dump box. In contact with Jessie Butler to find Ed's old pictures of the g2p target platform. Assuming helium is present in radiation thicknesses after scattering. Will update if there is any change. Tech-note with the radiation lengths can be found [https://userweb.jlab.org/~rbziel/g2p_radlengths.pdf here]
−	==2/11/2015==
−	Present: Chao, Jie, Min, Melissa<br>	+	==6/15/2016==
−	By Phone: Pengjia, Toby, Ryan, Ellie, Vince<br>	+
		+	Present: JP, Karl, Alex, Ryan, Toby, Chao, Jie, Vince, Ellie, Xiaochao, Kalyan  <br>
−	'''Feature Presentations:'''	+	No presentations. Just verbal updated
		+
		+	*Jie
		+	Jie gave a little more detail on the carbon cover from last week's slides. The carbon cover is a porous carbon sponge added to the BPM to help with radiation. This in itself shouldn't effect the pedestal but opening up the BPM to install it could have an effect. It's possible the pedestal change is also related to configuration changes in the target magnetic field. Jie will show more at meeting next week.
		+
		+	*Ryan
		+	Confirmed from Chao that DP is not corrected for ELOSS. Still waiting to hear back from Ed Folts on g2p helium bags.
	*Toby		*Toby
−	**Gave an update on dilution analysis.  The dilution factor is define as one minus the ratio of background yield over<br>total yield.  The background yield includes contributions from nitrogen, helium and the foil endcap on the target cell. <br>To extract the dilution factor he must tune the Bosted model (for helium and carbon) to match cross section data, <br>radiate the simulation results and take ratios to obtain necessary scaling constants, and then apply these scaling <br>constants to calculate the background yield.  For tuning the Bosted model, he is currently using cross section data  <br>from the UVa quasi-elastic database.  The kinematics do not match ours exactly, but this will work until g2p cross <br>sections are available.   He used a &chi;-squared minimization routine to determine the scaling factor for each kinematic. <br>He also showed the resulting cross sections ratios, which are used to determine the scaling factors &alpha;, &beta; and &gamma;.<br>Next he will apply the cross section ratios to yields from dilution runs to calculate the background yields and dilution <br>factor for the 2.2 GeV, 5T transverse setting, after which he will move on to other settings.  More details can be seen <br>in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/dilution021015.pdf here].	+	Getting Melissa's packing fraction code this week. Will use it to update packing fraction calculations.
−	==2/4/2015==	+	==6/8/2016==
−	Present: Chao, JP, Jie, Min, Melissa<br>	+	Present: JP, Karl, Alex, Ryan, Toby, Chao, Jie, Vince, Ellie  <br>
−	By Phone: Toby, Ryan, Pengjia, Karl<br>	+
		+	'''Feature Presentations:'''
		+
		+	*Ryan
		+	Gave an update on the radiation length calculation. He checked the energy loss calculation people did before and found out that we did not use the He bag during the experiment but before people built the He bag in the simulation. However the difference between He and air should not cause serious problem for us. More details can be seen in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_060816.pdf here].
		+
		+	*Jie
		+	Gave an update on the beam position problem. He worked together with Pengjia on this problem. The bpm database is updated so that the beam current dependence of the BPM is removed. Another problem is that the reported beam position would jump suddenly within the same momentum setting. Pengjia and he guess the pedestal of the BPM might be a possible reason. And between the two run they compared, a carbon cover was added which might influence the pedestal. So they did some study of the BPM pedestal values. The current cut Pengjia used before to select no-beam events is replaced by a more tight one. However, the results do not change much. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2016_0608_pedstal/yields_update_20160608.pdf here].
		+
		+
		+	==5/25/2016==
		+
		+	Present: JP, Alex, Ryan, Toby, Chao, Jie, Vince, Ellie  <br>
		+
		+	'''Feature Presentations:'''
		+
		+	*Toby
		+	Gave an update of his study on the scattering angle. The problem he mentioned on 5/11 has been solved. Both of the formulas are correct. However, he found that the central scattering angle jumped within one momentum setting for more than 3 deg. Chao mentioned that his calculation result does not show this behavior and they will discuss this offline. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/scatangle_talk_5.25.16.pdf here].
		+
		+
		+	==5/18/2016==
		+
		+	Present: JP, Karl, Alex, Ryan, Toby, Chao, Jie, Vince, Ellie  <br>
	'''Feature Presentations:'''		'''Feature Presentations:'''
	*Chao		*Chao
−	**Gave a status update on optics analysis. For the 2.2 GeV, 5T settings (longitudinal and transverse) there was<br>limited optics data taken. Instead, the 1.7 GeV optics matrix matrix was used for this setting, with a 0th order <br>correction for the longitudinal setting, and a 1st order correction for the transverse setting. He showed the <br>longitudinal setting as an example, applying the 1.7 GeV matrix and including the 0th order correction to center <br>the sieve holes. JP commented that, if the offset is large, there may be higher order effects to consider.  There <br>are no optics runs for the 3.3 GeV setting, so he plans to use g2psim to determine the optics matrix. He is <br>working on an optics technote, and a technote summarizing the last target field measurement. More details can <br>be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150204/Chao_WeeklyMeeting_02042015.pdf here].	+	Gave an update of the acceptance study. He used the elastic scattering data to calibrate the resolution of the simulation. He found that the simulation package does not treat the resolution of the beam position properly. Thus the simulation package is updated to generate the events according to the beam profile. With this new update, the resolution of the simulation agrees with the data. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20160518/Chao_WeeklyMeeting_05182016.pdf here].
−	*Min
−	**Gave an update on her acceptance study.  For this time, she improved the fitting at the virtual plane (for both <br> x/y and , and &theta;/&phi;) and projected the results onto the focal plane.  The corrections on the forward transport <br>function were incorporated into g2psim.  For the reverse transport function, the fit was done using all dp scan runs. <br>The simulation does not match with the data at the edges; this is due to the boundary conditions in the simulation.  <br>Min will try expanding the boundary to see if it better matches the data.  More details can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/02042015/02042015.pdf here].
−	*Melissa	+	==5/11/2016==
−	**Updated the data quality check for the 2.2 GeV, 2.5T setting to include RHRS runs.  In general the problem <br>settings on the RHRS are consistent with the LHRS.  She also gave an update on the packing fraction analysis; <br>there was a problem in the previous definition of the packing fraction.  The updated method requires some input <br>from cross section models.  The resulting packing fraction is slightly larger than the result from the previous <br>method.  Next she will work on extracting packing fraction values for other settings.  More details can be seen <br>in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Yields/Yields_02_03.pdf here].	+
−	*Jie	+	Present: JP, Karl, Alex, Ryan, Toby, Jie, Vince, Ellie <br>
−	**Calculated the energy loss using two methods; using his energy loss model (Monte Carlo, step by step), and <br>using a radiated cross section model (from Stein). He used a fixed initial energy and fixed scattering angle for <br>a carbon target, and didn't apply any acceptance cuts.  He compared the dp spectra for the two methods and <br>found that his energy loss model agrees well with the radiation model.  Next he will work on a full simulation <br>for a beam dependence study (once the acceptance is ready).  More details can be seen [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_02_04_radiative/2015_02_04_Simulation_updae.pdf here].	+
		+	'''Feature Presentations:'''
−	'''General Discussion:'''	+	*Toby
−	*Starting next week we will change the meeting start time to 9:30am.	+	Gave an update of the scattering angle calculation. He used two formulas from Pengjia and Chao to calculate the scattering angle and suggests that the results do not agree. People suggests that this two methods are equivalent and we should just use one of them. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/scatangle_talk_5.11.16.pdf here].
		+	*Ryan
		+	Gave an update of his study of the scattering angle dependence of the cross-section. He used the radiated Bosted model and calculated the cross-sections with three different scattering angle. And the results shows ~20% difference. More details can be seen in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_051116.pdf here].
−	==1/28/2015==	+	*Jie
		+	Gave an update on his study of the yield drift problem. He is still working together with Pengjia to correct the beam current dependence of the beam position. He summarized the beam current distribution for all production runs and found that ~90% of our data was taken with current less than 50 nA, where the beam position need to be corrected. He also studied the "sudden jump" of the beam position which means that the BPMA and BPMB readout did not changed much but the reported beam position changed a lot. It probably could be explained by the pedestal change but still need more study. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2016_0508_plots/yields_update_20160510.pdf here].
−	Present: Chao, JP, Jie, Melissa<br>
−	By Phone: Vince, Ryan, Toby, Min, Pengjia, Ellie, Alexandre<br>
		+	==4/20/2016==
		+
		+	Present: JP, Karl, Alex, Chao, Ryan, Toby, Jie, Vince, Ellie  <br>
	'''Feature Presentations:'''		'''Feature Presentations:'''
	*Ryan		*Ryan
−	**Gave an update on data quality checks for the 1.1 GeV setting.  He found that the spread in yields ranges <br>from 0.01% - 6.1%, with an average of ~2%. For this setting we also took runs on a short target cell (material <br>14).  For settings with a large spread, there was a correlation between beam drift and yield drift. Overall, this <br>setting seems ok.  Next he will move back to working on polarized radiative corrections. More details can be <br>in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_012815.pdf here], and a detailed summary <br>of the data quality check can be seen [https://hallaweb.jlab.org/wiki/index.php/G2p_1157_25T here].	+	Gave an final update of the nitrogen cross-section study of the saGDH experiment. The radiative correction is done and the uncertainty carry-over from the elastic tail analysis is 1.5%. The radiative correction is calculated in two different way: the classic unfolding and the ratio of un-radiated and radiated Bosted model. He also did a bin center correction and compared the result with Vince's calculation. Two methods agrees at a 1-2% level. The radiative corrected cross-section for each kinematics setting is summarized in his slides and he will prepare a tech note for the analysis. More details can be seen in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_042016.pdf here].
−	*Pengjia
−	**Gave an update on data quality checks for the 1.7 GeV setting.  For settings with a large spread in yields, <br>he looked at the correlation with the calculated scattering angle.  He found that in some cases the change in <br>yield was proportional to the change in scattering angle, but for some settings it was inverse proportional.  <br>He also showed an example of a setting where the yield was drifting, but there was no change in the scattering <br>angle.  He tried applying raster cuts to see the effect on the yield, but first needs to find a way to calculate the <br>charge while including the raster cut.  There was some discussion how this could be done; it may be possible to <br>use the Happex DAQ, as it is triggered by helicity.  More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/01282015/yield_drift_20150128.pdf here].
		+	==4/13/2016==
−	'''General Discussion:'''	+	Present: Karl, Chao, Ryan, Toby, Jie, Vince, Ellie  <br>
−	*Toby will start replaying RHRS runs today, hopefully they will be done by the end of the week.	+
		+	'''Feature Presentations:'''
−	==1/21/2015==	+	*Jie
		+	Gave an update on his study of the yield drift problem. Last time he showed some plots which indicates that the beam position might not be accurate and he did some study on this problem. He found out that the BPM readout shows some linear relations with the beam current. After carefully check the data, it seems that only the BPM B have this correlation. And this problem could be found in all beam energy settings. The uncertainty of beam position is very large if this problem is not corrected. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2016_0404_beamcurrent_plots/yields_update_2016_04_13.pdf here].
−	Present: Jie, Min, Chao, JP, Kalyan, Melissa<br>	+	*Ryan
−	By Phone: Pengjia, Vince, Ryan, Toby, Karl<br>	+	Gave an correction to his presentation on last week. He mentioned there was a mistake when he compared the formulation for the full internal bremsstrahlung tail and the angle-peaking approximation. And the results agree after the mistake was corrected. More details can be seen in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_041316.pdf here].
−	'''Feature Presentations:'''	+	==4/6/2016==
−	*Melissa	+	Present: JP, Karl, Chao, Ryan, Toby, Jie, Vince, Ellie <br>
−	**Gave a summary of data quality checks for the 2.2 GeV, 2.5T, transverse setting.  There are several momentum  <br>settings with a significant spread (>2%) in the yields.  In most cases, the spread in yields seems to be correlated  <br>with a change in beam position, which often corresponds to beam down time during the run period. Examples of <br>problem settings can be seen in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/Yields/Yields_01_21.pdf here], and a summary of all settings is available [https://hallaweb.jlab.org/wiki/index.php/G2p_2254_25T here].	+
−	*Chao	+	'''Feature Presentations:'''
−	**Gave an update on the status of optics for the RHRS.  For the longitudinal and transverse settings at 5T, only a <br>few optics runs were taken, so the plan is to use the 1.7 GeV optics matrix for these settings.  He also included a <br>summary of the RMS value of each kinematic variable (&delta;, &theta; and &phi;) for each setting, and commented that <br>the RMS value for y_tg is around 3-4mm, but this is a rough estimation as the fitting is not as good for this variable.  <br>Next he will test 2.5T transverse optics matrix on the 5T settings to see if it works.  His slides are available [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150121/Chao_WeeklyMeeting_01212015.pdf here].	+
−	**The simulation package has been updated to cover the RHRS and include some upstream geometries.  The most <br>recent version of g2psim is available through github here: https://github.com/asymmetry/g2psim	+
−	*Min	+	*Ryan
−	**Gave an update on her acceptance study. For this time, she combined all dp scan runs in order to do the <br>corrections at the virtual plane, which was then projected onto the focal plane. The agreement at the virtual <br>plane looks good, but there is still some disagreement at the focal plane. Next she will fit the reverse transport <br>functions and compare target plane variables. More details are available in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/01212015/01212015.pdf here].	+	Gave an update on his radiative correction study. He already studied the uncertainty for the elastic tail and he continued his study with the inelastic radiative correction. He explained how the angle approximation was applied in the internal bremsstrahlung. There is an equivalent correction in the angel approximation which is dropping the soft photons compare with doing a full integration. Difference between these two calculation is 5-10% for proton. He is still working on applying the calculation to other nuclei like Nitrogen. More details can be seen in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_040616.pdf here].
		+	*Toby
		+	Gave an update on the his calculation of the asymmetry and cross-section. He applied the dilution factor calculated from the data to the asymmetry calculation. On the other side, he also applied the radiative correction factor calculated from the MAID model to the asymmetry calculation. He then applied the same factors to the cross-section calculation and got the cross-section and cross-section differences. The dilution seems not continuous and JP suggests to do a deeper study for each momentum in the longitudinal setting to understand what is the reason, for example the yield problem studied by Jie. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/asym_xs.pdff here].
−	==1/14/2015==
−	Present: Chao, Jie, JP, Melissa<br>	+	==3/23/2016==
−	By Phone: Pengjia, Ryan, Toby, Ellie, Karl, Min, Vince, Alexandre<br>	+
		+	Present: JP, Karl, Chao, Ryan, Toby, Jie, Vince, Ellie  <br>
	'''Feature Presentations:'''		'''Feature Presentations:'''
	*Jie		*Jie
−	**Gave an update on the dp simulation, specifically trying to understand why the simulation result for elastic dp was <br>narrower than the data. Comparing the data (with just PID cuts) to the simulation result (using full acceptance, and <br>a raster diameter of 2cm), the simulation is narrower than the data. However, if he applies acceptance cuts to the data <br>and simulation, and uses a beam size of 4mm (which matches with the data), the results show a better match between <br>data and simulation.  He also tried dividing the beam spot into 5 different zones, and looked at the resulting dp <br>distribution for each. He did see a shift in the central value of dp between zones, however this shift was not seen in the <br>simulation. He also compared the shift in &theta; and &phi; for the 5 zones.  JP commented that the &theta; distribution in<br>the data is symmetric and centered around zero, while the simulation result is not.  It is possible that this is due to the <br>fact that Jie is using the old SNAKE model; he will get the updated version from Min and see if it makes a difference. <br>More details can be see in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_01_12_dp/Simulation_update_2015_01_12.pdf here].	+	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 [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2016_03_22_plots/yields_update_2016_03_23.pdf here].
−	*Pengjia	+
−	**Posted his false asymmetry results to the ELOG.	+	==3/9/2016==
−	**Working on data quality check for the 1.7 GeV, 2.5T setting.  It looks like the spread in yields in some settings is <br>strongly dependent on the scattering angle.  JP suggested looking at beam position or other raw variables, since the <br>scattering angle is a calculated value and depends on optics.  It seems most settings with problems correspond to a <br>break in time when the runs were taken, which may suggest a problem with the spectrometer. Pengjia will look into <br>this next.  More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/01152015/data_quality_20150115.pdf here].	+
		+	Present: JP, Karl, Chao, Ryan, Toby, Jie, Vince, Ellie <br>
		+
		+	'''Feature Presentations:'''
	*Toby		*Toby
−	**Gave an update on his yield drift study for the 3.3 GeV setting.  For this time, he looked at the target field (central <br>NMR value) over the 2.34 GeV momentum setting, a period of about 6 hours.  While there are some jumps in the signal, <br>there isn't a consistent drift like is seen in the yields.  However, there is a period where the signal jumps significantly; he <br>will look into a possible cause for this. He also looked at the scaler BCM counts and trigger rates for these runs.  There <br>was no noticeable drift in the scaler rates, but the beam current was not stable during this time.. He also computed the <br>"scaler yield" by dividing the total triggers by the BCM counts and saw a drift similar to what is seen in the normalized <br>standard yield. Previous to these runs being taken, there was a flood in the hall resulting in a power outage. It's possible <br>that the drifting is a result of systems not being stable while these runs were taken. More details can be seen in his <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/scaler_yield_drift_talk.pdf here].	+	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 [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/asymtalk_030916.pdf here].
	*Ryan		*Ryan
−	**Working on a data quality check for the 1.1 GeV, 2.5T setting.  In general the setting looks pretty good; the maximum <br>spread is 10% and the minimum is 0.01%, with an average of ~2% spread. Fewer runs were taken in this setting, and the <br>runs were taken consecutively, resulting in smaller spreads overall. In addition, there was data taken at this setting at <br>3 different momentum settings, all looking at elastic, and all on the same material.  Next he will try to determine the <br>problem for the settings with a large spread (~10%). More details can be seen in his slides [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_011415.pdf here].	+	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 [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_030916.pdf 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 [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2016_03_01_raster_plots/yields_update_2016_03_09.pdf here].
−	==1/7/2015==
−	Present: Chao, Jie, JP, Min, Kalyan, Jixie, Melissa<br>	+	==2/24/2016==
−	By Phone: Yunxiu, Vince, Pengjia, Toby, Ryan, Ellie, Karl, Todd, Nilanga, Haiyan<br>	+
		+	Present: Karl, Chao, Ryan, Toby, Min, Ellie, Jie  <br>
	'''Feature Presentations:'''		'''Feature Presentations:'''
−	Each student gave a short update on their analysis projects since the last collaboration meeting on November 14th:	+	*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 [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/scatangle_dilution_022416.pdf here].
−	*Melissa
−	**Method for packing fraction analysis is complete; the packing fraction values for each material still need to be <br>extracted.  This will probably take ~1 week, but the yield discrepancies need to be understood before it can be <br>completed.  She is also working on data quality checks for yields, specifically the 2.2 GeV, 2.5T setting.  After these <br>projects are complete she will work on the PbPt check using elastic asymmetries.  More details can be seen in her <br>slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/melissac/talks/MCummingsCollabMeeting_Jan.pdf here].
−	*Toby	+	==2/17/2016==
−	**Focusing on data quality checks of yields for production runs.  He has completed the 2.2 GeV 5T settings, both <br>longitudinal and transverse, and the 3.3 GeV setting.  The 2.2 GeV 5T settings have few problems, but the 3.3 GeV <br>has many momentum settings where the yields drift over time.  He sees a similar drift in the left and right arm data.  <br>He is still trying to figure out the cause for the drift.  In addition, he is working on tuning the Bosted model to helium <br>and carbon dilution runs to simulate the background for dilution analysis, with a goal of finishing the dilution analysis <br>by mid-march.  More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/01.07.15.pdf here].	+
−	**Information on data quality checks can be found on the wiki [https://hallaweb.jlab.org/wiki/index.php/G2p_data_quality here].	+
−	*Jie	+	Present: JP, Jixie, Chao, Ryan, Min, Ellie, Jie  <br>
−	**Looked at the effect of changing the scattering angle on the cross section for carbon, nitrogen, helium and hydrogen. <br>This may help explain the discrepancy we see in the yields, but is problem not the only cause.  He is also working on <br>finishing the dp simulation, which should be done soon, and will begin working with Min to learn more about the acceptance <br>study.  More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/jie/2015_01_06_pbosted/2015_01_06_Simulation_update.pdf here].	+
		+	'''Feature Presentations:'''
	*Chao		*Chao
−	**Gave an update on the status of optics analysis. He is finishing up the 2nd iteration of the optics calibration; the LHRS <br>is complete and the RHRS has one setting to go (1.158 GeV). For the 2.2 GeV, 5T, transverse setting, there is no full <br>dp scan, so the longitudinal data taken at that energy setting will be used. Once the 2nd iteration of the calibration is <br>complete, he and Min will compile a technote on the optics study. He has also modified the geometry part of the g2psim <br>package to make it more configurable. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20150107/Chao_WeeklyMeeting_01072015.pdf here].	+	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 [http://hallaweb.jlab.org/experiment/g2p/collaborators/chao/20160217/Chao_WeeklyMeeting_02172016.pdf 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 [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_021716.pdf here].
		+
		+
		+	==2/10/2016==
		+
		+	Present: JP, Karl, Alex, Jixie, Toby, Chao, Ryan, Min, Ellie, Vince  <br>
		+
		+	'''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 [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_021016.pdf here].
		+
		+
		+	==2/3/2016==
		+
		+	Present: JP, Karl, Alex, Jixie, Toby, Jie, Chao, Ryan, Ellie, Vince  <br>
		+
		+	'''Feature Presentations:'''
	*Min		*Min
−	**Working on the acceptance study. In the focal plane, there seems to be good agreement between simulation and data. <br>In the target plane, in the &theta; vs &phi; plot, there seems to be a shift in &phi; for all dp settings; it seems to be a linear<br>correlation with dp. Next she will work on a correction for &phi;-target vs dp and compare target plane variables. To finish the <br>good septum, straight through setting it will probably take 1-2 months, then an additional 1-2 months for the other 2 septum <br>settings. More details can be see in her slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/01072015/01072015.pdf here].	+	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 [http://hallaweb.jlab.org/experiment/g2p/collaborators/mhuang/acceptance/02032016.pdf 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 <br>
		+	By Phone: Jie, Chao, Ryan, Ellie  <br>
		+
		+	'''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 <br>
		+	By Phone: Jie, Chao, Ryan, Toby, Ellie  <br>
		+
		+	'''Feature Presentations:'''
	*Ryan		*Ryan
−	**He has completed a draft for a PRC paper on unpolarized He3 cross section data. He still needs to complete the He3 radiative <br>correction analysis for saGDH, but is waiting on updated nitrogen cross sections for saGDH. He is also working on the carbon/ <br>nitrogen ratio for saGDH, but is waiting on updated analysis from Vince before continuing.  He is also working on data quality <br>checks for production runs for the 1.1 GeV setting, and is starting to look into polarized radiative corrections. More details can <br> be seen in his slides [https://userweb.jlab.org/~rbziel/CollabMeeting_12015.pdf here].	+	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 [https://userweb.jlab.org/~rbziel/Weekly_Meetings/g2p_011216.pdf here].
−	*Pengjia	+	*Toby
−	**Calculated the false asymmetry by comparing the asymmetry before and after applying detector cuts. He found the false <br>asymmetry to be small; less than 200 ppm for all energy settings.  He's also working on a data quality check for the 1.7 GeV <br>data set. More details can be seen in his slides [http://hallaweb.jlab.org/experiment/g2p/collaborators/pzhu/01072015/false_asym_20150107.pdf here].	+	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 [http://hallaweb.jlab.org/experiment/g2p/collaborators/toby/g2p%20meetings/targunc.pdf here]
	'''General Discussion:'''		'''General Discussion:'''
−	*Yields stability/overall data quality check is the main issue at this time.
−	*Progress of acceptance study looks good, but could become an analysis bottleneck.
		+	*Chao updated his optics technical note.
		+	*There is no meeting next week due to the Hall A collaboration meeting.
	----		----
−	==Jan-June 2015==	+	==Jul-Dec 2015==
		+	[[Minutes_Jul2015_to_Dec2015]]
		+	----
		+
		+	==Jan-Jun 2015==
	[[Minutes_Jan2015_to_June2015]]		[[Minutes_Jan2015_to_June2015]]
	----		----
−	==July-Dec 2014==	+	==Jul-Dec 2014==
	[[Minutes_July2014_to_Dec2014]]		[[Minutes_July2014_to_Dec2014]]
	----		----
−	==Jan-June 2014==	+	==Jan-Jun 2014==
	[[Minutes_Jan2014_to_June2014]]		[[Minutes_Jan2014_to_June2014]]
	----		----
−	==June-Dec 2013==	+	==Jun-Dec 2013==
	[[Minutes_June2013_to_Dec2013]]		[[Minutes_June2013_to_Dec2013]]
	----		----
Line 516:		Line 1,405:
	----		----
−	==Jan-March 2012==	+	==Jan-Mar 2012==
	[[Minutes_Jan2012_to_Mar2012]]		[[Minutes_Jan2012_to_Mar2012]]
	----		----
−	==July-Dec 2011==	+	==Jul-Dec 2011==
	[[Minutes_July2011_to_Dec_2011]]		[[Minutes_July2011_to_Dec_2011]]
	----		----
−	==Jan-June 2011==	+	==Jan-Jun 2011==
	[[Minutes_Jan2011_to_June_2011]]		[[Minutes_Jan2011_to_June_2011]]
	----		----

---

Latest revision as of 11:57, 29 July 2021

Minutes of the weekly analysis meetings

---

Agenda

07/29/2021

Present: JP, David

• David showed a zoomed in plot of the Q^6 Delta_LT scaling agreed upon last week, and JP and David both agreed that this made the high point look unnecessarily bad. David agreed to make a similar version of the Q^4 plot to decide between next week, and include the Q^6 plot in the current paper draft.
• David mentioned that he found Chao's internal presentation of an elastic study which yielded a contribution to the acceptance systematic of 4%. JP commented this was likely to be the dominating systematic for the acceptance and suggested that David use this to obtain a back of the napkin calculation of the XS systematic. JP also suggested that this systematic could be representative of our overall uncertainty in the 1.15 scaling to match the g2p data to the Bosted model, and that we could potentially quote this number to anyone who raises issue with the scaling factor.
• There was a brief discussion of the Drechsel paper JP found, he suggested Karl would probably have access and that the discussion in that paper would likely feed what we should say about d2 in our paper.
• David mentioned that he has been working this week on making a draft of the paper with Karl's comments from last week and JP's comments from this week, and would try to finish in the next day or two to send to the Spokespeople.
• David will be traveling next week but available for a meeting, JP suggested if the draft was sent out this week it would be a good time for a short meeting for Karl, JP, and any others to share their current thoughts and comments on that iteration of the draft.

07/22/2021

Present: Alexandre, JP, Karl, David

• David showed a number of slides showing delta_LT multiplied by various powers of Q2. We commented that Drecschel shows Q6/M2 delta_LT in his paper. Also the 2004 E94010 polarizabilities showed the same quantitty. So there is precedent for this. David will produce a zoomed version of the plot. He also showed delta_LT/gamma_0, although he has low confidence in the present error bars. He will revisit and he and Karl will try to add RSS data, Maid and pdfs to see if the transition to the predicted scaling at very large Q2 is at all visible at this very low Q2.
• JP Asked David to look at threshold again, and to try to dig out Chao's evaluation of the acceptance uncertainty from the elog and old wiki presentations.
• Alexandre reminded that there is a lot of good old information in the elog : https://hallaweb.jlab.org/dvcslog/g2p/
• We switched the weekly meeting time to 10:30am on Thursdays.
• Karl will be on travel next week, but expects to be available for the weekly meeting.

05/01/2019

Present: JP, Karl, David Feature Presentations :

• David

Showed a number of slides building up the 2.5T 2.2GeV dilution one step at a time to try and analyze any outstanding issues. These plots showed severe edge effects from the momentum settings on all run types. J.P. and Karl suggested fixing this by doing a fit to one of the yield, and then using an offending momentum setting to find a dp correction to the fit and apply it everywhere. The plots also showed several momentum settings where the centroid appeared to be shifted, David promised to do some detective work to try and figure out why.

Verbal Updates:

None

12/06/2018

Present: Karl, Chao, David Feature Presentations : None. Verbal Updates:

• David

Discussed a final issue with Chao leading to simulated peaks being smeared too wide, because of a smearing parameter in the input file being too big. Said he should have final 5T Longitudinal packing fractions next week, and is prepared to have final 2.5T 2.2GeV packing fractions once Snake Model is complete. Also showed a plot of Gamma 2 indicating that the cost to using just the Material 8 data for the 2.2GeV 2.5T would be costly, more than doubling the total error bar and changing the central value slightly, highlighting the need to use one of the other methods discussed to complete the analysis.

• Chao

Chao said that he will be needing to leave the field and seek a job in industry starting in January, but said he would finish updating the Snake model before he goes so that the packing fraction analysis can be completed with the new method.

10/04/2018

Present: J.P., Karl, Chao, David Feature Presentations :

• David

Showed several slides on the current status of the 2.5T packing fraction. With several issues fixed, the carbon peak shows good agreement with the helium peak subtracted by using a helium simulated elastic peak and subtracting it scaled by the appropriate packing fraction. For the production data, this process was repeated with an iterative process for the packing fraction of helium, showing no sensitivity to initial guess and converging on relatively reasonable packing fraction results. J.P. and Karl suggested that the fit between the simulation and the data is not perfect, it may be a reasonable enough comparison to function. However, for Material 7, the elastic yield is much sharper than for Material 8, and while the latter matches the shape of the simulation well, the former looks very different. Karl suggested to look into how the materials compare to the simulation for other settings, and J.P. noted that it should be impossible to compare the integrated yield to the simulation if their shape is different. It was also suggested to check on the status of the septa, and see if the simulation has accounted for any possible changes in it.

09/27/2018

Present: J.P., Karl, David Feature Presentations :

• David

Showed several slides on the current status of the 2.5T packing fraction. Showed first a carbon slide showing better agreement, but still a few very jagged areas in the simulated carbon peak, and mentioned that he has defaulted to comparing dilution data with helium in it, as the optics data proved very hard to work with. J.P. mentioned that in addition to the jagged behavior at the top of the peak, it is worth looking into why the simulation peak seems wider than the production data very slightly at the base. Using the scale factor provided by this carbon comparison, David showed several slides of the resulting packing fractions, doing a linear fit to an 0.4 and 0.6 packing fraction simulated yield. J.P. and Karl gave several suggestions for dealing with the Helium elastic peak, since that has not been done yet. J.P. also suggested it was a good idea to take the whole Nitrogen peak when integrating to find the packing fraction, rather than just part of it. David mentioned he would also talk to Chao about the odd behavior at the top of the elastic peaks and ask for suggestions. The packing fractions at this stage seem to give reasonable values, though everyone commented it will be important to subtract the Helium elastic peak before finalizing the packing fractions, and apply this same method to one of the 5T energy settings to compare to Toby's Ratio method.

Verbal Updates:

None

09/13/2018

Present: Chao, J.P., David Feature Presentations :

None

Verbal Updates:

• Chao

Working on smoothing out the acceptance correction for the 5T Transverse 2.2 GeV energy setting.

• David

Showed a few slides, indicating that the proper cuts give very good agreement for the carbon data in the elastic region. However, it was discussed that there are many jagged peaks above this region that Chao says should not exist. Chao gave a few suggestions for improving the simulation's agreement. David also asked about how to scale properly by the luminosity, and how to actually put the packing fraction in the simulation, as the setting in the simulation only changes the energy loss according to Chao. J.P. and Chao explained that David should just scale the 0.6 packing fraction simulation by 0.6, and so on, but that each element would need to be scaled separately and added together (so for 0.6 packing fraction, total yield = 0.6 Nitrogen + 0.4 Helium + 0.6 Proton, etc). J.P. also suggested to try simulating an empty cell as the helium peak should be clean and match well.

08/09/2018

Present: Chao, Karl, David Feature Presentations :

None

Verbal Updates:

• Chao

Working on finishing transverse data, doing another replay, save root files on his local computer so it will not be diluted anymore, will calculate transverse acceptance soon. Won’t be at meeting next week, in two weeks will show final 5T 2.2 GeV transverse acceptance.

• David

Working on comparison between carbon g2psim and data for 2.2GeV 2.5T, asked Chao a few technical questions about weighting the g2psim histograms in C++ or Python.

08/02/2018

Present: Chao, J.P., Karl, David Feature Presentations :

• Chao

Chao showed a few slides of final longitudinal acceptance correction, which he said look good except for a discontinuity at the start of the quasi elastic peak for longitudinal. Karl suggested checking the same plots with no dp cut just to compare. Chao also suggested that we make a repository of all g2p codes and simulations so that we can easily access whatever we need.

Verbal Updates:

• David

David mentioned that he’s working on learning to use g2psim with Chao’s help, so that he can tweak it and produce simulated yields for use in the Oscar PF method.

07/26/2018

Present: Chao, Karl, David Feature Presentations :

None

Verbal Updates:

• David: thanked Chao for sending g2psim, asked a few technical questions about operating it. Chao noted that it’s important to run each material seperately, so for production data, to run nitrogen, hydrogen, and helium independently and convolute them. David also showed the functional form of the uncertainty in g2 as a function of the uncertainty in the packing fraction, Karl suggested to provide rough numerical values and David agreed to do so next week.

• Chao: Sent David the current working version of g2p sim, very nearly done with 5T longitudinal acceptance. Will show cross sections for 5T longitudinal next week.

07/19/2018

Present: Chao, J.P., Karl, David Feature Presentations :

• Karl

Karl started off with some overview slides to try and get a majority of the work done by the end of the summer before people get busy. He voiced that the biggest question is whether we are using a data or model cross section, where the data is the attractive option if possible to make our results model independent, but the model may be a better option if the data is impossible or will take too long, as we can more or less publish the 5T data now, and the 2.5T data (pending pf analysis) He also asked if by the end of the meeting, we could identify all outstanding tasks and give an estimate for how long they will take to complete. Barring december, said that we should plan to have a paper submitted to PRL by the end of the year.

Moments paper work to be done yet: Low x contribution to BC integral Low nu contribution to gamma0

• David

David showed a talk describing the Oscar Rondon packing fraction method. J.P. voiced that since the method requires scaling the simulation to carbon data, it cannot be used in the elastic region since you would need a different scale factor for carbon or nitrogen, so the only region to apply the method is the very inelastic one. Chao said right now he doesn’t think the simulation can do inelastic data, but that once he applies Ryan’s tweaked Bosted model, he thinks it will be able to. There was some discussion about the error bar for this packing fraction method, and J.P. said that the standard deviation of both the carbon and the production data in the chosen region would need to be applied to get the total error.

There was brief discussion of going back to the unfinished elastic fit method if all else fails, since all that should need to be done is finding a way to deal with quasi elastic contamination.

David also showed plots for the scattering angle for 2.5T 2.2GeV that show that even once the materials are separated out, all the data seems choppy at high E’ values.

Verbal Updates:

• Ryan

Finally, David relayed a few questions from Ryan. Karl said he doesn’t care which paper is published first and we should just publish them in the order we are able to. He also voiced that Ryan’s hyperfine question was something we could discuss offline or at the next meeting as time ran short. With regard to the question of using our cross sections, the eventual conclusion was that if Chao is able to match the timetable he provided today that it may be feasible to use g2p cross sections for all 2.2GeV energy settings.

• Chao

Chao says within 2 weeks he can get cross section for longitudinal. Estimates within 1 month will have acceptance for 2.2 GeV, 5T Trans+Long, and another 6 weeks for 2.2GeV, 2.5T Trans. He said that 3.4 GeV has no elastic so he’s not sure there will be an acceptance. Karl and JP suggested he then prioritize the three 2.2GeV settings.

David estimated 6-7 weeks to get the packing fraction assuming we can get simulated yields. Chao agreed to send g2p simulation package to David so he can help with adding in missing models (Ryan Bosted-tweak?) and start learning to use it for applying the Oscar Method.

07/12/2018

Present: Chao, J.P., Karl, Ellie, David Feature Presentations :

• Karl

Showed the plots that he showed at Trento, and mentioned that there is a lot of interest right now specifically in the hyperfine result, as Ryan's calculation of delta 2 disagrees noticeably with the most recent papers. Said that we should try and get the paper out by the end of the year, so we should try and finish both acceptance and pf by the end of summer. Suggested that next week we sit down to figure out a game plan for how to do that.

Verbal Updates:

• David

Mentioned that he and Karl got in touch with Oscar Rondon to ask a few questions about his packing fraction method, which we hope to try. Also said that he is currently re-playing the packing fraction rootfiles for several gradations of cut in case we want to study the cut dependence of the ratio method. Also working on producing plots for the scattering angle fit for just the carbon data, and for each production material independently. Karl asked Chao about how good the simulation is for the transverse settings, Chao said he has been focusing on the simulation for the 5T 2.2GeV settings but could maybe look into it.

• Chao

Chao said he is continuing to work on the acceptance, and has been looking into the super-elastic peak J.P. asked about last week. 

05/31/2018

Present: Chao, J.P., Karl, Ellie, David Feature Presentations :

• Chao

Fit correction to the yield for 7 momentum settings in quasielastic region. Checked if the correction is stable and showed plot of yield for a 2.2GeV 5T run with the correction applied. J.P. says effective correction should be fine to fix relative difference. Discussed discontinuity at nu = ~459 MeV, Chao said he can fit that region to try and remove it. Karl asked about the motivation for the correction, Chao explained it is a fit that he found that works. See agendas section for plots.

Verbal Updates:

• David

Still trying to work on packing fraction analysis. Modified code from Toby to re-add 5T settings, can nearly reproduce Toby's results but scaled down by a factor of 3.5 for all 5T energy settings. Sent an email to Toby and trying to look into what variable change could cause this difference between 2.5T and 5T.

05/24/2018

Present: Chao, J.P., Karl, David Feature Presentations :

None

Verbal Updates:

• Chao

Still working on data corrections for the acceptance discontinuity, will have results next week. Also looked into beam position and found how to retrieve data from EPICS to help David, though warned that this does not give the real beam position, but the beam jumps should still show up in the raw data.

• David

Working on packing fractions and the to-do list of suggestions Ryan left last week, is able to reproduce Toby's ratios, working on doing a fit to the scattering angle to determine how the simulation might change with the tighter cut. J.P. suggested that taking the average scattering angle required correcting the data to an average as well. David also mentioned that he fixed the issue with getting null results from Toby's code for 5T, but still cannot reproduce the 5T packing fractions correctly.

05/17/2018

Present: Chao, J.P., Karl, David Feature Presentations :

None

Verbal Updates:

• David

Showed a few plots of the spread and average for each momentum setting involved in the asymmetry discrepancy analysis for the 2.5T data. However, J.P. noted that some of the means didn't quite make sense given the error bars of the points involved, and it became clear that there were a few mistakes in the normalization of the parameters for these plots. Further, differences between the global run by run asymmetry plot and the momentum-setting ones lead to the conclusion that there must have been a mistake in the presentation of the plots. David said he would re-do this section of the analysis more carefully and try again next week to determine if any of the momentum settings seem pathological.

04/26/2018

Present: J.P., Karl, David Feature Presentations :

None

Verbal Updates:

• David

Showed a reprisal of his update on the Left and Right HRS Asymmetry comparison for the 2.2 GeV 2.5 T data to catch J.P. up, and mentioned that he will produce a plot of total asymmetry plotted against run number by using a run by run asymmetry, at Ryan's suggestion. J.P. and Karl both agreed that it would not be wholly unacceptable to add a systematic to the moment data if the issue could not be resolved otherwise, but that it would be ideal to solve it and not have to do that. J.P. also suggested that since the asymmetry seems to be unstable for both arms around the relevant point, that perhaps something happened with the beam, and suggested cross comparing to Jie's BPM analysis to try and determine if there was a beam jump or something similar around the time that the inconsistency occurs. Also showed a table of packing fractions generated from Toby's scripts with different acceptance cuts. Said that the inclusion/exclusion of the RunStatus 6 Packing Fraction runs seems to have little impact on the Packing Fractions generated, but that using Ryan's tight cut in place of any of Toby's loose cuts produces packing fractions for the 2.2 GeV 2.5 T setting that seemed to Karl to be more reasonable. J.P. and Karl both suggested that one standard cut should be used for everything, preferably Ryan's tight cut since that has been well documented and discussed already. David said he will produce a re-done version of Table 6.4 from Toby's thesis, with all of the packing fractions generated using Ryan's tight cut.

04/05/2018

Present: Chao, David Feature Presentations :

None

Verbal Updates:

• Chao

Still working on trying to resolve acceptance issue, before J.P. left for China he advised that Chao try cuts on various variables that go into the acceptance, like the Raster and the BPMs, to try to quantify what the effect on the acceptance is. Chao said he is currently working on doing this.

• David

Said that he compared error bar on Gamma 2 to the variation in Gamma 2 caused by the discrepancy in the asymmetry between the left and right arms for the 2.5T 2254 MeV data, and that the total errorbar (statistical+systematic) is about 33% of the value of the moment, while the discrepancy causes a 20% change, for comparison. Also discovered that Toby's rootfile code appears to produce root files formatted differently from the ones his packing fraction script calls so working on eliminating the differences so that they can actually run together.

03/29/2018

Present: Karl, David Feature Presentations :

• David

Presented an update on the 2.5T 2254 MeV data asymmetry comparison, showing the result of replaying the data with a tighter momentum cut. Unfortunately, the tighter momentum cut seems to worsen the chi^2 comparison rather than improve it. Also showed and discussed with Karl an attempt to determine how serious the effects of the asymmetry discrepancy are on the final value for Gamma 2. The discrepancy seems to be responsible for a 20% variation in Gamma 2, but Karl said this value should be compared to the size of the existing error bar to determine if just throwing a systematic on and using the original data would be a valid way to go. Also re-showed the comparison of data taken on the first sweep up the momentum spectrum to data taken going back down, and showed that the largest discrepancy only occurs on the second set of runs, though no glaring change is notable in the log book.

David also mentioned that he's started work on trying to replay Toby's root files to re-generate the packing fractions for the 2.5T data.

Verbal Updates:

None

03/23/2018

Present: Chao, David Feature Presentations :

• Chao

Trying to resolve the issue Ryan discovered with acceptance not being continuous for production runs, using Dummy run to try and look at background and subtract out the effects of the target cell itself, runs are scaled by live charge so are proportional to cross section, so can be subtracted. This subtraction removes everything outside the target cell, effectively, the background, but does not consider the difference between foil target and extended target. Cut simulated target into 1mm slices to investigate-- for real target, there is no cross section difference between z=0, z=-13, and z=13, for any kinematic variable. Chao's conclusion is that either simulation doesn't match well, *or* the acceptance should not be dependent on the z position in the target. See slides attached to agendas section.

Verbal Updates:

• David

Left arm replay finished and asymmetries regenerated for 2.5T 2.2GeV runs, ran into issue with many of the right arm runs failing repeatedly on the batch farm. Going to try running interactively with Screen and using a different queue to avoid timeouts.

03/09/2018

Present: Ryan, J.P., Karl, David Feature Presentations :

None.

Verbal Updates:

• Ryan

Still waiting on Chao to get back to him about cross section issue, said Chao's explanation makes sense to him. J.P. asked about question dealing with the Y acceptance, but Ryan commented that he hasn't talked to Chao about it yet. Ryan agrees that the target length is the only thing different between carbon and production runs and that this is likely the source of the cross section issue.

• David

Replay finally working, ran into issue with some of the files coming out un-filled from the batch farm, but this is an issue Ryan has seen before and Ryan advised that he replay just the failed runs repeatedly until all of them function.

11/27/2017

Present: Ryan, Ellie, J.P., Karl, David Feature Presentations :

None.

Verbal Updates:

• Ryan

Discussed progress on the PRL with Karl and J.P., and whether or not the acceptance should be included.

11/17/2017

Present: Ryan, Ellie, J.P., Karl, David Feature Presentations :

None.

Verbal Updates:

• Ryan

Corresponding about Hyperfine results with Franziska Hagelstein, got numbers for delta_1 and delta_2, Karl suggested that this is good but evidence that since Ryan's data is on the Arxiv, people are going to want to use it and this is more incentive for us to be expedient in getting to publish. Ryan is working on finishing the hyperfine paper and intends to include both 2.2 GeV 2.5 T data, and the g1 point.

• Karl

Has approved Toby's thesis, after edits that provide more detail on the choice of the ratio method over the fit method for the packing fractions.

• David

Still working on tight dp cut replay, has all of Toby's dilution and packing fraction scripts running locally, Ryan and Karl suggested trying to replay dilutions with a tighter acceptance.

• Chao

Trying to get acceptance study running on JLab batch farm. Longitudinal study for the acceptance is done.

10/27/2017

Present: Ryan, Ellie, J.P., David Feature Presentations :

• Chao

Acceptance study for the longitudinal settings is just about finished. Elastic peak agrees well with theory, continuity of nu spectrum is good. Needs a conversion between slow and fast raster current. Transverse spectrum has not as good continuity, will be fixed soon.

Verbal Updates:

• David

Still working on tight dp cut replay, showed proof of principle doing dp cut on bin by bin basis, that seems to give more evidence that this is the issue, but aims to make it better with the count by count replay.

• Karl

Showed plots of g2p packing fractions vs SANE packing fractions, discussed the elastic fit method with Toby to determine that the .3 packing fraction is not good, but wants to investigate the suspiciously high 2.5T packing fractions, since SANE data never goes above .74.

10/06/2017

Present: Ryan, Ellie, J.P., David Feature Presentations :

None

Verbal Updates:

• Ryan

Working on the PRL for the ChiPT paper, just started.

• David

Working on resolving systematic shift in 467 Nu point for 2.2 GeV 2.5T asymmetry between left and right HRS, showed normalized yields, J.P. and Ryan suggested a tight dp cut. Also discussed the suspiciously good chi^2 generated with the method J.P. suggested before, J.P. said he thinks it is fine that the chi^2 is small but that it is necessary to evolve the kinematics of one arm to the other one before combining the 2.5T asymmetries. Also mentioned working on a cross check for the 5T data for g2 with Toby and Ryan, but has a sign error, it was suggested for David to fix the sign of the asymmetry to the theory or the elastic asymmetry peak.

09/22/2017

Present: Ryan, Chao, Ellie, Karl, David

Feature Presentations :

None

Verbal Updates:

• Ryan

Sent model codes to David, discussed dilution's odd behavior at nu > 1000 MeV, explained that previously he and Toby have switched to a model above 950 MeV abruptly from data. Said that packing fraction systematic error doubled after Toby fixed the radiative correction issue. Karl and Ryan discussed the issue of Toby assuming the ratio of carbon to nitrogen was a flat 15%, where Ryan was able to find a paper plotting it vs W.

• Chao

Unable to speak, but will present 5T 2.2 GeV acceptance next week.

• David

Has generated g2 for 2.5T 2.2GeV data, will refine over the coming week.

09/06/2017

Present: Karl, J.P., David, Ellie

Feature Presentations :

• David

Showed a study on the left and right arm HRS asymmetry comparison for 2.5T. Was able to replicate Ryan's results for 5T asymmetries, J.P. and Karl suggested redefining the chi^2 in terms of the uncertainty of both arms to remove ambiguity. 2.5T 2.2 GeV asymmetries show good agreement with the exception of three data points, which David is investigating, after noting that the runs going into those data points jump by about 5 days and change target material. Karl and J.P. suggested it was also important to obtain information about whether Toby's dilutions should change based on the target material. More details on his slides can be found here.

Verbal Updates:

None

08/23/2017

Present: Ryan, J.P., Toby, David, Alexandre

Feature Presentation :

None

Verbal Updates:

• Ryan

Discovered the the divergence in XS from Toby was because the radiation lengths were flipped in Toby's analysis-- TA comes after TB (T after and T before). Toby promised to re-run the code and ensure

• David

Working on Left+Right HRS 2.5T comparison still, trying to get Chi^2 for 5T comparison to be as good as in Ryan's analysis. Using same runs, LHRS asymmetry agrees with Ryan's but RHRS differs for three data points.

08/09/2017

Present: Ryan, Chao, J.P., Karl, David

Feature Presentation :

None

Verbal Updates:

• Chao

Working on optics runs to complete acceptance study, trying to figure out a way to work around not having definitive BPM Results.

• Ryan

Trying to get signatures from committee on thesis, still waiting to hear back from Toby about dilution issues.

• David

Working on Left+Right HRS 2.5T comparison, have preliminary results but with a very large Chi^2 of ~25, trying to work on account for second order effects to knock that down and make sure it is viable to combine the data from both arms.

08/02/2017

Present: Ryan, Karl, David, J.P.

Feature Presentation :

None

Verbal Updates:

• David

Still working on HRS asymmetry comparison for the LHRS and RHRS, installing ROOT and configuring local coding environment. Ryan agreed to help guide David through setting up his environment.

Discussed intelligent magnet power supply, which David will investigate communicating with via USB, irrelevant to the g2p collaboration.

• Ryan

Thesis edits essentially complete, L+R HRS Comparison had an angle difference of .3 degrees Ryan and Karl discussed trying to get a better dilution and packing fraction from Toby to deal with other issues in 2.5 T 2.2 GeV data Ryan should be able to get shell of Hyperfine results soon

• Karl

Karl asked Xiaochao to contact Jie about finishing the BPM analysis, Jie responded that he will not finish the analysis. In terms of administrative issues, Karl agreed to add David to g2p mailing list so that he can take over sending out weekly meeting emails from Ryan.

07/19/2017

Present: Ryan, Toby, Karl, David

Feature Presentations :

• Toby

Showed an update on the dilution and packing fraction calculation for 2.5T. This is an issue at large nu where the fit to the packing fraction and dilution grow large where the model expects them to level off. Toby thinks this might be an issue with the radiative scale factor he is applying to the data. There is also some questions about the choice of acceptance cut used to generate the quantities. He chose a large acceptance cut to improve statistics but this might have systematic effects causing the rise. He will repeat the analysis at a few difference acceptance cuts to check this effect. More details on his slides can be found here.

Verbal Updates:

• David

Working on HRS asymmetry comparison for the LHRS and RHRS

07/12/2017

Present: Ryan, Toby, Karl, Ellie, David, Chao

Feature Presentations :

• Ryan

Showed beam energy values for the experiment run period on production runs. There are some bigger than expected fluctuations. To first order the effect of this is small (Mott XS variation) but the question is how this could effect calibrations, such as the BPM calibration. More details on his slides can be found here.

Verbal Updates:

• Toby

2.5 T packing fraction values. Taking into account yield drifts gives a systematic error on the order of 15% at 2.2 GeV 2.5 T. Looking into 1.7 GeV settings next

• David

Working on HRS asymmetry comparison for the LHRS and RHRS

• Chao

Working on acceptance simulation. Running simulation for the production runs. Slow going because he can only runs a handful of jobs at a time.

07/05/2017

Present: Ryan, Karl, Toby, J.P., Chao, David

General Discussion:

• Batch farm is prioritizing multi-threaded jobs so this will impact g2p replay and also Chao's acceptance simulation timeline.

• Toby is going to start looking at the 2.5T dilutions this week.

• David has generated asymmetries but results are consistent with zero so he will try larger binning (up from 10 MeV)

06/28/2017

Present: Ryan, Toby, David, Karl, Chao, JP, Alexandre, Xiaochao, Ellie

General Discussion:

• 2.5T data quality. Based upon error bars from a quick moment analysis of the 2.5T data from Ryan it appears that the 2.2/1.7 GeV data is useful for publication with Q2 values of approx 0.04 GeV2 and 0.02 GeV2, respectively. The 1.1 GeV data error bars are very large, which is in part due to the very small asymmetry prediction at that low Q2 (0.009 GeV2).

• Toby is leaving to start a job on July 24. He will try and get something together for the dilution and packing fraction analysis for the 2.5T settings.

• Chao is making good progress with the longitudinal acceptance for the carbon data. He is able to produce a continuous spectrum with good agreement in the overlap regions at large nu. Unfortunately there is no overlap around the delta-resonance. He will do a similar study except at the transverse settings next.

• David is going to work on the data quality check for the 2.5T asymmetries. His first step is to produce g2p asymmetries and compare to results from Ryan and Toby.

06/21/2017

No meeting because of Hall A collaboration meeting.

06/14/2017

Present: Ryan, Karl, Toby, J.P.,Chao

Feature Presentation :

• Ryan

Showed the results of a quick analysis of the 1.7 and 1.1 GeV 2.5 T settings. The 1.7 GeV data looks pretty good and can most likely be used going forward. There is one momentum setting just previous to the delta where the majority of the data was taken with a mismatched septa and dipole configuration, so it is not included in these slides. He will try including this data to see the effect it has on the results. It should probably be OK for the asymmetry. The 1.1 GeV data looks worse statistically, which related to the much smaller asymmetry that we see as we go to lower and lower Q2. As we go to lower Q2 we also have the added complication of the Christy fit we're using for the unpol XS getting worse and worse. Going forward Ryan will do a quick moment analysis of this data. More details on his slides can be found here.

• Toby

Showed different methods for calculating the low-x portion of the BC sum rule. These include the polarized PDF's and Hall B model. The problem is that none of these methods are really applicable at the g2p kinematics (PDF's hold down to Q2 = 1 GeV2), and that the low-x portion of the integral must be a sizable contribution for the BC sum rule to hold. Going forward we will most likely assume that the BC sum rule holds and use that assumption to place a limit on the low-x behavior of g2 at low Q2. More details on his slides can be found here.

06/07/2017

Present: Ryan, Karl, Toby, J.P.,Chao, Ellie

Feature Presentation :

• Ryan

Showed the results of a quick analysis of the 2.2 GeV 2.5 T settings. The goal of this analysis was to check the overall quality of the data and includes the combined statistics of both the RHRS and LHRS. The overall statistical precision of the data is pretty good considering the much lower target polarization of the 2.5T settings (15% on average compared to the 70% for the 5T runs). Going forward he will do a similar study for the 1.1 GeV and 1.7 GeV settings and also complete a very preliminary moment analysis of these settings. These settings also need a completed dilution and packing fraction analysis slides.

Verbal Updates:

• Jie

Published his BPM tech-note update to the wiki.

• Chao

Summarized his acceptance study progress. So far he has applied his 8mm raster cut method (+/- 15mrad in ph and 20 mrad in th) to the elastic carbon long. setting and gets 5% agreement between the simulation and data. He is able to drastically reduce the uncertainty in the raster cut by cutting on current and not size. The timing information of the raster is known very well. He knowns the time the raster spends inside the area of the cut and the time it spends outside. The ratio between these two times is scaled to the total charge. He is currently applying this to all the carbon dilution data at longitudinal to see how this procedure works at other P0. He estimates this will take 2-3 weeks. After that he will move onto the transverse setting and estimates that will take an additional 1-2 months to complete.

05/31/2017

Present: Ryan, Karl, Toby, J.P.,Chao

Feature Presentation :

• Toby

Showed an update on his g2 moment calculations. His moments included the BC sum rule and also DeltaLT. From his analysis it was concluded that it is very difficult to verify the BC sum rule at low Q2 because of the lack of data at low x. The DeltaLT results look much better. More details on his slides are found here.

Verbal Updates:

• Jie

Still working on his BPM tech-note/update.

• Chao

Planning on talking with JP about his acceptance study update. Had to leave early to go to another meeting.

05/24/2017

Present: Ryan, David, Karl, Toby, J.P., Jie, Ellie

Feature Presentation :

None

Verbal Updates:

• Jie

Still working on his BPM tech-note/update. Hopes to have it done by next week. This might also be his last g2p meeting before he starts his new job. Will also add his thesis to the wiki.

05/17/2017

Present: Ryan, David, Karl, Toby, J.P. Chao

Feature Presentation :

• Ryan

Showed an analysis for an explanation for why the 2.2 GeV Longitudinal polarized DS does not go to zero below the pion production threshold after tail subtraction. His idea is that the elastic radiative events come from a different part of the acceptance than the inelastic events. This effect could be potentially large if a large acceptance cut is used. The big unknown in this analysis is what is the exact angle difference. With the current reconstruction/simulation status it's very difficult to determine. In the future, if the simulation is able to reproduce the angular acceptance then the tails can be calculated and weighted for the simulated acceptance. This also raises potential problems for getting a polarized DS from an asymmetry and cross section calculated with different acceptance cuts. For now, the analysis will proceed with the old method and assume one scattering angle. Ryan will check the results of using a tight asymmetry and tight cross section cut to see how the tail subtraction is effected. More details on his slides are found here.

• Chao

Showed an update on the optics simulation and he is currently trying to beat down the systematic error from making a raster cut. He is currently cutting on raster current as opposed to raster size to improve the uncertainty. With a raster cut the simulation is much better able to reproduce the data.

05/10/2017

Present: Ryan, Jie, David, Toby, Ellie, JP

Feature Presentation :

• Ryan

Showed an analysis update of the results section of his thesis and includes analysis of all of the 5T settings. He evaluated the g1 moments and the hyperfine splitting contributions for g1 and g2. More details on his slides are found here.

05/03/2017

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

Feature Presentation :

• David

Showed an update for calculating the acceptance correction by normalizing to the elastic cross section. His uncertainty in this method is slightly better than the results Toby showed before and his dominant uncertainty is the scattering angle reconstruction and it's effect on the Mott XS and elastic form factors. He will look into further separating the quasi-elastic and elastic peaks by subtracting out the elastic tail for helium-4. More details on his slides are found here.

4/26/2017

Present: Ryan, Jie, David, Karl, Toby, Ellie

Feature Presentation :

• Ryan

Showed results of a parallel asymmetry analysis between Toby and Ryan. The asymmetries agree very well and the only slight difference is at the longitudinal setting. This difference is a result of slightly different acceptance cuts used in the analysis and goes away if the same cuts are used. More details on his slides are found here.

• Toby

Posted an update on last weeks slides to include a model comparison to his calculated cross sections. His slides are found here.

4/19/2017

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

Feature Presentations :

• Toby

Showed a comparison between calculating polarized cross sections using a model and using data. In the data method he multiplies the raw asymmetry by the raw cross section with no dilution correction. In the model method he applies the dilution to the asymmetry and then uses a unpolarized proton model (radiated). The two results agree pretty well except for the 3.3 GeV setting where the yield drifts present problems with the dilution and cross section calculation. We will most likely have to use a model at this setting. More details on his slides are found here.

Verbal Updates:

• Chao

Talked about using the raster cut in the simulation to match data and simulation for the acceptance. He's going to soon try and apply this raster cut method across the momentum settings at the longitudinal setting and see how well the simulation can match data. He's currently using a 30 mRad phi cut, which is significantly larger than the cut Toby is using and will the systematic uncertainty from knowing the cut boundary. There is going to be an additional systematic from using a raster cut when it comes to calculating the accumulated charge. He is looking into this.

4/12/2017

Present: Ryan, Jie, David, Karl, Toby, JP, Ellie

No presentations this week. Toby and Ryan are working on comparing their asymmetry results to confirm that their methods agree. Jie's graduation date is May 9 and he is still working on finishing up his thesis.

3/29/2017

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

Feature Presentations :

• Ryan

Showed an update including the Gamma1 and GDH moment calculations. The results have very good statistical error bars when compared with the Hall B data and also his integration of the Hall B data agrees with the published Hall B results. More details can be found in his slides here.

• Chao

Showed an update on the simulation for Run 5612. He is able to reproduce the edges of the acceptance better if he places a very tight cut on the raster size. This suggests a beam position reconstruction issue. Going forward he is going to look at the uncertainty introduced by this raster cut and see which has the larger contribution to the uncertainty: raster cut or acceptance cut. More details can be found in his slides here.

3/22/2017

Present: Ryan, Jie, David, Karl, Toby, JP, Chao

Feature Presentations :

• Ryan

Showed a comparison between the Bosted model and low Q2 SLAC data. The agreement between data and the model is better at larger Q2 and around 15% at the 5T setting kinematics. Ryan is waiting on an updated model from Eric Christy that includes the low Q2 data in the fit. More details can be found in his slides here.

• Toby

Also showed a comparison between the Bosted model and the SLAC data but included a preliminary g2p cross section as well. The agreement is at the 15% level with our data. More details can be found in his slides here.

• David

Showed a method for calculating the helium-4 elastic cross section from g2p empty dilution runs. He compares the g2p data to the Rosenbluth result from the MSW (McCarthy-Sick-Whitney) form factors and get's agreement at the 10% level. He will look into adding systematic uncertainty estimates to both his measured and calculated quantities. He will also investigate the 'Delta E' term in the elastic peak radiative corrections. More details on his slides can be found here.

Verbal Updates:

A request was made by Eva-Maria Kabuss for some g2p slides to present at DIS 2017 (April 3-7).

3/15/2017

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

Feature Presentations :

• Chao

Showed an update on the optics and acceptance simulation. He showed that for a carbon run with no liquid helium and at the longitudinal target configuration he is able to match data to simulation with a very tight acceptance cut. He is working on expanding this cut to reduce the overall systematic uncertainty in the acceptance. Super elastic events and carbon excited states make expanding this range difficult. More details on his slides can be found here.

Verbal Updates:

• Jie

Graduation date is set for May 9, 2017.

3/8/2017

Present: Ryan, Jie, David, Karl, Toby, JP

Feature Presentations :

• Ryan

Showed an update on how he is extracting g1 from the longitudinal data and evolving it to a constant Q2. He also showed a preliminary calculation of the gamma0 moment, which agrees well with the current Hall B measurements and chiral perturbation theory predictions. More details on his slides can be found here.

3/1/2017

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

Feature Presentations :

• Ryan

Showed an update on the systematic error analysis going into the asymmetries, polarized cross sections and radiative corrections. Currently the dominating systematic error is from the angle reconstruction and use of an unpolarized model to create the polarized cross sections. The angle reconstruction error is amplified at low angles because of the strong Mott dependence. The unpolarized cross section systematic could be reduced in the future by substituting in g2p data for that component. More details on his slides can be found here.

• Jie

Gave an update on the BPM calibration process. Showed that there is a strong position dependence to the off-sets determined from Harp scans. Through the reconstruction procedure he is unable to reproduce the location of the harp scan points because of this position dependence. More details on his slides can be found here.

• Toby

Presented the status of the dilution analysis for the 3.3GeV settings. The analysis is complicated by the large yield drifts seen in the data. He is still trying to figure out a method to give reasonable dilution results at this setting. But whatever method he settles on will most likely come with an increased level of systematic error. More details on his slides can be found here.

2/22/2017

Present: Ryan, Toby, David, Jie, JP

Feature Presentations :

No feature presentations this week. Everyone is planning on presenting next week.

2/15/2017

Present: Ryan, Toby, David, Jie, JP

Feature Presentations :

• Jie:

Showed an update the BPM calibration. There was some discussion on the base assumptions Jie is making in removing potential position dependence on some calibrations constants (b-/b+). More details on his slides can be found here.

General Discussion :

• Toby:

Updated target polarizations are available now.

• Ryan:

HERMES publication from 2013 of new BC Sum Rule calculation at Q2 = 5 GeV2. Data is consistent with 0 but with large error bars.

2/8/2017

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

Feature Presentations :

• Ryan:

Showed the final systematics for the inelastic and elastic RC's. The end result is 2-3% for the elastic tail and 3-5% for the inelastic RCs. More details on his slides can be found here.

General Discussion :

• Toby:

Updating his systematic uncertainty on the target polarization analysis.

2/1/2017

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

Feature Presentations :

• Jie:

Gave an update on the BPM analysis. Still have trouble solving the position jumps. More details on his slides can be found here.

• Ryan:

Showed the outline of the g2p radiative corrections procedure, including the polarized elastic tail and RADCOR and POLRAD formulations of the inelastic RCs. Also presented systematics for the unfolding procedure. He will next finalize the theory systematics for the RCs. More details on his slides can be found here.

• Chao:

Gave an update on the acceptance study. He showed that at the longitudinal setting the shift from 0 in the theta_tg histogram is caused by the target field. The effect is more pronounced at transverse settings. More details on his slides can be found here.

General Discussion :

• Toby:

g2p dilutions are now available on the wiki.

1/18/2017

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

Feature Presentations :

• Jie:

Hoping for a May graduation with his thesis split between three topics (g2p is one). Point was made that Jie must finish his BPM study before graduation because at this point he is the only one that can do it. More details on his slides can be found here.

• Toby:

Hoping for a May graduation with a close-to-final g2 his goal for his thesis. Finishing up the dilution analysis for 3.3 GeV 5T. More details on his slides can be found here.

• Ryan:

Hoping for a June-August graduation with a close-to-final g2/hyperfine point his goal for his thesis. Finishing up the g2p radiative corrections procedure setup. More details on his slides can be found here.

• Chao:

Gave an update on the acceptance study. He is still having a hard time matching the simulation to data. More details on his slides can be found here.

General Discussion :

• Karl:

is looking into the EG1b data for our highest Q2 settings as the parallel component for g2.

1/11/2017

Present: Ryan, Toby, Karl, Jie, David, Chao

Feature Presentations :

• Ryan:

Showed the effect a 0.3 degree scattering angle difference between HRSs would have on the data. Calculated this difference using models and then compared the data to it. The data is consistent with a straight line fit at 0, so the statistics of g2p are not sufficient to make a definitive statement. Also showed a calculation for the uncertainty in the out-of-plane polarization angle using a psuedo Monte-Carlo method. The uncertainty is around 1%. Details of his slides can be found here.

1/04/2017

Present: Ryan, Toby, Karl JP, Jie,

Feature Presentations :

• Ryan:

Showed an update on the comparison between the LHRS and RHRS asymmetries for 2.2GeV 5T transverse. Using course 70 MeV bins and cutting out runs with large livetime and charge asymmetry he was able to get good agreement between the two spectrometers. The agreement is independent of the out-of-plane polarization angle correction. There is some question about the effect of the minor difference in the scattering angle between HRS's and the asymmetry. He will present on this difference at the next meeting. More details on his slides can be found here.

• Jie:

Still looking into the BPM calibrations and the source of the BPM position jumps that don't see a corresponding yield change. He hopes to have this analysis wrapped up by the end of January. More details on his slides can be found here.

• Other news:

At the 1/18/2017 weekly meeting we're planning on having a discussion on the analysis path forward. The primary focus on this discussion will be the experimental cross sections.

12/21/2016

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

Feature Presentations :

• Toby:

Showed an update on the packing fraction analysis with a new method that is similar to his dilution calculation. This method gives a lower uncertainty than his elastic fit method. His two methods agree within the uncertainties for almost all of the settings. He will check the few kinematic settings where this isn't true and also try to pin down the systematic error from using the Bosted model to scale C12 to N14. More details on his slides can be found here.

• Other news:

Vince's last day at g2p meetings. Good luck at your new job Vince!

12/14/2016

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

Feature Presentations:

• Jie:

Showed a status update on the BPM calibration procedure. More details can be found in his slides here.

• Chao:

Still having trouble matching the width of the simulation peaks to peaks from data. Even getting rid of all apertures did not sufficiently widen the simulation peak. He is continuing to look into it. More details can be found here.

12/07/2016

Present: Ryan, Toby, Karl, Vince, JP, Jie, Alexandre

Verbal Updates:

• Toby

Working on getting his dilution code back up and running

• Ryan

Working on asymmetry comparisons between the LHRS/RHRS at 2.2 GeV 5T Transverse.

• Jie

Talking with Pengjia still about the BPM calculation procedure. Will give an in-depth update on the status of the BPM analysis at the next meeting.

11/30/2016

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

Feature Presentations

• Ryan

Showed an update on the out-of-plane polarization angle calculation. The calculation agrees with Chao's result but still seems too large (40 - 65 degrees). Chao is working on confirming the results. Details of his slides can be found here.

• Toby

Showed an update on the packing fraction analysis. He presented final values for all settings except for 1.1 GeV 2.5 T. The difficulty at this setting is that the quasi-elastic peak is barely separable from the elastic peak so he is unsure of how to fit it. This is also a problem at the other 2.5 T settings and is manifest in the larger systematic uncertainties. Details of his slides can be found here.

Verbal Updates:

• Chao

working on out-of-plane polarization angle calculation and will also confirm the proton elastic simulation results for Toby.

• Jie

Talking with Pengjia still about the BPM calculation procedure.

11/23/2016

Present: Ryan, Karl, JP, Jie, Kalyan, Alexandre

• Jie

Discussed BPM calibration method

• Ryan

Working on calculating the out-of-plane polarization angle, with help from Chao. Hoping to confirm method with Chao and present something soon.

11/16/2016

Present: Ryan, Toby, Karl,Chao, Jie, Vince, Alexandre

Feature Presentations

• Jie

Showed an update on the BPM calibration procedure. His correlation method for calculating the pedestals improves the uncertainty but does not affect the position reconstruction. In the calibration procedure there is an offset term that as large variations between calibration points. Pengjia fit this constant for current dependence but it is also possible it might have some positional dependence. Jie is going to talk with Pengjia about this. More details on his slides can be found here.

Verbal Updates:

• Toby is working on finalizing the uncertainties for the packing fraction analysis and is running into some issues with g2psim.

• Ryan is working on calculating the out-of-plane polarization angle, with help from Chao.

11/02/2016

Present: Ryan, Toby, Karl, JP, Vince, Alexandre

Feature Presentations

• Ryan

Showed a brief update on calculating the out-of-plane angle correction to the perpendicular polarized cross sections. He will talk to Chao about how to make this calculation using the reconstructed variables in the replayed ROOT files. More details on his slides can be found here.

• Toby

Showed a slide on the yield spectra for the elastic runs in PF analysis at all kinematic settings. The nitrogen and helium peaks are only clearly visible at the 2.2 GeV 5T transverse setting, so he will need to adjust his fitting routine to account for this at the other settings. More details on his slides can be found here.

10/26/2016

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

Feature Presentations

• Ryan

Showed an update on the polarized radiative corrections using POLRAD at the g2p kinematics (non-constant scattering angle). He showed that using the same angle fit for all the input spectra (as opposed to individual fits representing measured data) the systematic error was similar to that of data taken at a constant scattering angle. For this study he used the MAID 2007 model. He recommends using models for the RC'ing of g2p data but those models could be tuned and checked using measured data. More details on his slides can be found here.

Verbal Updates:

• Chao

Working on the optics and acceptance simulation and tuning the simulation aperatures. Showed a short slide with better agreement between data and simulation. Still working on improving this.

• Jie

Working on the BPM position calibration procedure.

10/19/2016

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

Feature Presentations

• Toby

Showed an update on his method for calculating the packing fraction, along with his estimate for the systematic uncertainty. He's hoping to finalize the results for the 5.0 T settings within the next few weeks. More details on his slides can be found here. There was some discussion that his uncertainty of ~8% in the fitting method is overestimated as described in the slides, so hopefully the systematic uncertainty is at the 10% level, maximum.

Verbal Updates:

• Chao

Working on the optics and acceptance simulation and tuning the simulation aperatures.

• Jie

Working on the BPM position calibration procedure. Still trying to fully understand Pengjia's method.

• Ryan

Working on setting up inelastic radiative corrections procedure for changing angle of g2p.

10/12/2016

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

Feature Presentations

• Jie

Showed final results for the BPM pedestal uncertainty using his new correlation method for the 2.2 GeV 5T transverse setting. The uncertainties are about a factor of 3-4 better than previous and are approx. 1mm and 1mrad at the target. He is moving on to finishing this study at other settings and also looking into the BPM calibration procedure and beam position jumps. More details on his slides can be found here.

Verbal Updates:

• Chao

Working on the optics and acceptance simulation. Believes that the previous mismatch he showed with data and simulation at bigger angular acceptance was due to the simulation aperatures blocking more events than seen in the data. Current size estimates of the aperatures is from a combination of g2p survey and historical Hall A information.

• Toby

Working on packing fraction results and updating the systematic error analysis. Hoping to finalize shortly.

• Ryan

Working on setting up inelastic radiative corrections procedure for changing angle of g2p.

10/05/2016

Present: Ryan, Toby, Karl, Ellie, Jie, JP, Jixie

Feature Presentations

• Ryan

Showed the reconstructed angle for a loose cut on all of the LHRS g2p production data. The fit is a combination of a linear and exponential fit; this form is suggested from a Jixie ELOG post. For the most part there is good agreement with the data to the fit, and outliers from the fit is a potential criteria for selection of good runs. He used these fits to mimic g2p data and test RC procedures on data at different angles. He found that he could do RC's with small systematic error if he used the same fit for all input spectra. This is not the case for g2p data, so he's working on improving the method. More details on his slides can be found here.

Verbal Updates:

• Jie

Working on the BPM pedestal issue. He's now considering correlations between all channels in the BPM pedestals. This slightly increases his uncertainty but it is still smaller than Pengjia's result and helps alleviate the triple peak issue.

• Toby

Working on packing fraction results and updating the simulation calculations needed for the cross section ratio input.

• SPIN 2016

Chi-PT calculations of the polarizabilities are still bad. NEED DATA!

9/21/2016

Present: Ryan, Toby, Karl, Chao, Jie, JP, Jixie, Kalyan, Vince

Feature Presentations

• Jie

Showed an update on the BPM pedestal calculation. Found a correlation between the pedestals on BPM channels. By using a rotated coordinate system, he can decouple the correlation. This allows for a reduced uncertainty in the BPM pedestal uncertainty contribution to the BPM calculation. More details on his slides can be found here. Will work on finalizing the updating uncertainty calculations and continue with checking the BPM calibration.

• Ryan

Showed the reconstructed angles for three different asymmetry cuts for both the transverse longitudinal asymmetries. There is a difference between the hot-spot angle in the transverse asymmetry. The RHRS accepts smaller angles in the transverse configuration but this cannot account for the difference in the HRS asymmetries between L/R. More details on his slides can be found here. He will try different cuts on different variables to try and find a set that gives agreement between the LHRS/RHRS.

• • NO MEETING NEXT WEEK BECAUSE OF SPIN 2016

9/14/2016

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

Feature Presentations

• David

Showed a statistical analysis between the LHRS and RHRS asymmetries for the 2.2GeV 5T transverse/longitudinal data. Concluded that for long. data the two spectrometers are statistically measuring the same thing. Further work still needs to be done on for the transverse asymmetries. His slides can be found here.

• Toby

Showed an updated packing fraction calculation where he replaces fits to the quasi-elastic and quasi-elastic contamination with the Bosted model. His packing fractions are in much better agreement with this method and the consensus is that the fit method was driving the large differences previously seen. He was given suggestions on trying to better quantify the quasi-elastic contamination, including using other models and separating the kinematic regions using acceptance cuts. More details can be found in his slides here.

• Jie

While on the schedule, he will present next week.

9/7/2016

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

Feature Presentations

• Chao

Gave an update on the acceptance study of the 5T longitudinal setting. He's currently working on tuning the resolution of the simulation package. He finds that he can match the width of the elastic peak for a small range in theta and phi target but as he increases that range his simulation produces too narrow of a spectra. He is working on fixing this issue. His slides can be found here.

• Ryan

Showed a comparison between the 5T longitudinal asymmetries using different acceptance cuts. He demonstrated that within our statistical error bars we do not need to make a bin-centering correction to the asymmetries for the longitudinal setting. He also tried to see if a model accurately described the asymmetry change with angle but was not successful. More details can be found in his slides here.

8/31/2016

Present: Ryan, Toby, Ellie, Karl, Jixie, Vince, Jie, Alexandre, JP

Feature Presentations

• Jie

Gave an update on the BPM pedestal analysis. He showed results from the pedestal analysis of beam trip runs for both the Happex DAQ and HRS DAQ. HRS DAQ has cleaner pedestals but the HRS DAQ is less precise. The pedestal shift seen in the HAPPEX DAQ is continuos with time. He will continue to look at the BPM calibration procedure and try and quantify the effect the pedestals have on the BPM uncertainty. More details can be found in his slides here.

Verbal Updates:

• Ryan

Continuing to look at HRS asymmetry angle dependence

8/24/2016

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

Feature Presentations

• Toby

Showed an update on the packing fraction analysis. He has been able to successfully fit the two elastic peaks (N2 and He4) and quasi-elastic peak to produce packing fraction results. He also presented an alternative calculation to the packing fraction, just using the helium peak from production and a dummy/empty run. His two methods agree at the ~10% level but differ greatly from what Melissa showed previously. Toby will continue to look at his fits and see if there is room for improvement there because there is some fit dependence on the result. One suggestion was to fit the simpler dummy run He4 elastic peak and use those fit parameters in the production runs. More details can be found in his slides here.

Verbal Updates:

• Ryan

Continuing to look at HRS asymmetry angle dependence

• Jie

Working on understanding Pengjia's BPM code.

8/17/2016

Present: Ryan, Toby, Ellie, Chao, Vince, Jie, Alexandre

Feature Presentations

• Ryan

Showed a comparison between asymmetries between LHRS and RHRS for the three 5T settings: 2.2 GeV long/trans and 3.3 trans. Overall there is good agreement between the HRS's, and the biggest disagreement is between the arms at the 2.2 GeV trans setting. Ryan will check that scattering angle dependence of the asymmetries next to see if this can improve the agreement. Currently the RHRS scattering angle reconstruction is not correct. Chao believes this is a coordinate system issue in his code. Slides can be found here.

Verbal Updates:

• Chao

Back at JLab for one year. First thing he will focus on is correcting the scattering angle reconstruction for the RHRS replay. After this he will move onto the acceptance study for the 5T longitudinal setting.

• Jie

Working on understanding Pengjia's BPM code.

• Toby

Working on updating the target polarizations for the HRS's. Found a bug in his code in converting UNIX times. Also developing two parallel methods to determine packing fraction, one using fits and another using simulation.

8/03/2016

Present: Ryan, Toby, Karl, Vince, Jie, Alexandre

No Presentations.

Verbal Updates:

• Jie

Got code for BPM calibration from Pengjia. Still waiting on some further explanation from Pengjia on the code. He will focus on the 5T settings first in the calibration

• Toby

Working on the g2psim package and using it for calculating the packing fraction. Replayed RHRS 5T transverse data, and according to Chao it should have final optics.

• Ryan

Has a working model dilution code.

7/27/2016

Present: Ryan, Toby, Jie, Vince, Kalyan, JP, Karl

Feature Presentations:

• Jie

Working on trying separate two peaks in the BPM pedestal runs. It does not appear that the two peaks can be filtered based upon the frequency using an FFT. Moving forward he will check how the double peaks affect BPM calibration uncertainty and check the BPM calibration procedure. More details can be found in his slides here

• Ryan

Presented raw asymmetries with three difference acceptance cuts to highlight the angle dependence on the asymmetry in the delta-region. Was able to produce a similar trend in models using scattering angles from the data. Going forward will try to find acceptance cuts that select similar numbers of events and see if the ratio between data points is the same as the ratio of model points to do a bin-centering type correction. More details can be found in his slides here

7/20/2016

Present: Ryan, Toby, Jie, Vince, Alexandre , Kalyan, Karl, Ellie

Verbal Updates:

• Jie

Looking into 2-peak pedestal issue for the BPMs. Checking to see if the two peaks are at different frequencies and can be separated. If they cannot then the 2-peak pedestals will increase the BPM reconstruction uncertainty at the target to ~3-4mm (from 1-2mm) for runs with the double peak. Previously Pengjia did not consider any RMS value above 2000 in his analysis.

• Toby

Still working on getting the g2p simulation package to match g2p data. Able to now produce elastic peaks in the correct locations to match data. Requesting that someone familiar with g2psim make a post on the wiki detailing the variables in the output of the simulation root tree because they are not straight-forward to understand.

• Ryan

Completed setting up a python version of the radiated model code. Uses MAID/Hall B for the polarized and Bosted for the unpolarized. Does the unpolarized and polarized elastic tail but only uses RADCOR for the inelastic radiating.

7/13/2016

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

Feature Presentations:

• Jie

Showed a comparison between the BPM pedestals calculated during dedicated pedestal runs and during beam trips. The two methods agree, so Jie is moving forward with the beam trip method to fill in gaps for BPM pedestal calculations. His next step is to move onto checking the BPM calibration. More details can be found in his slides here

Verbal Updates:

• Toby

Still working on getting the g2p simulation package to match g2p data. This will be used for calculating the packing fraction

• Ryan

Working on producing radiated models to compare to the g2p data.

7/6/2016

Present: Ryan, Jie, Kalyan, JP, Karl, Ellie

Verbal Updates:

• Jie

Working on comparing pedestal values from dedicated pedestal runs and from beam-trip's. He's mostly found agreement and is working to settle the few outliers. After this he is moving onto to checking the BPM calibration.

• Ryan

Working on setting up radiated models to compare with the radiated data asymmetries.

6/29/2016

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

Feature Presentations:

• Jie

Gave an update on the BPM pedestal issues. In his slides he shows the pedestal histograms to demonstrate that the pedestal value is really shifting with time. Some pedestal's also exhibit a multi-peak structure, which ultimately will effect the uncertainty of the BPM calibration. He also showed the effect of using different BPM pedestal values for different runs and effects the BPM reconstruction. The resulting BPM position change is much larger than simulation would predict indicating that again that the BPM pedestal value is really changing with time. Going forward he will look to determine an accurate BPM uncertainty from the fluctuating pedestal values. More details on his slides can be seen here.

Verbal Updates:

• Toby

Working on updating Melissa's packing fraction code to use simulation to match the quasi-elastic peak, instead of relying on fits because the packing fraction result is highly-sensitive to the fit parameters.

• Ryan

Working on raw asymmetries and comparing them with Toby to make sure they agree.

• Vince

Has updated ChiPT calculations that he will send out over the mailing list.

6/22/2016

Present: Alex, Ryan, Toby, Jie, Vince, Kalyan

Feature Presentations:

• Toby

Received Melissa's packing fraction code. Found that there is now a difference in the nu histograms for the elastic runs when compared to what Melissa used in her analysis. Melissa's tech-note shows only a single elastic peak, but new root-files have both a elastic nitrogen and helium peak. The two peaks are separated by about 5 MeV at E0 = 2.2 GeV. The existence of an additional peak effects the applicability of Melissa's fitting routines to these new root-files. Toby will contact Melissa and see what she can provide. Slides are here.

Verbal Updates:

• Jie

Jie is still talking with Pengjia over the BPM pedestal issue. He hopes to have slides for next week's meeting.

• Ryan

Ed Folts confirmed the presence of helium bags in the septum bores and local dump box. In contact with Jessie Butler to find Ed's old pictures of the g2p target platform. Assuming helium is present in radiation thicknesses after scattering. Will update if there is any change. Tech-note with the radiation lengths can be found here

6/15/2016

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

No presentations. Just verbal updated

• Jie

Jie gave a little more detail on the carbon cover from last week's slides. The carbon cover is a porous carbon sponge added to the BPM to help with radiation. This in itself shouldn't effect the pedestal but opening up the BPM to install it could have an effect. It's possible the pedestal change is also related to configuration changes in the target magnetic field. Jie will show more at meeting next week.

• Ryan

Confirmed from Chao that DP is not corrected for ELOSS. Still waiting to hear back from Ed Folts on g2p helium bags.

• Toby

Getting Melissa's packing fraction code this week. Will use it to update packing fraction calculations.

6/8/2016

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

Feature Presentations:

• Ryan

Gave an update on the radiation length calculation. He checked the energy loss calculation people did before and found out that we did not use the He bag during the experiment but before people built the He bag in the simulation. However the difference between He and air should not cause serious problem for us. More details can be seen in his slides here.

• Jie

Gave an update on the beam position problem. He worked together with Pengjia on this problem. The bpm database is updated so that the beam current dependence of the BPM is removed. Another problem is that the reported beam position would jump suddenly within the same momentum setting. Pengjia and he guess the pedestal of the BPM might be a possible reason. And between the two run they compared, a carbon cover was added which might influence the pedestal. So they did some study of the BPM pedestal values. The current cut Pengjia used before to select no-beam events is replaced by a more tight one. However, the results do not change much. More details can be seen in his slides here.

5/25/2016

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

Feature Presentations:

• Toby

Gave an update of his study on the scattering angle. The problem he mentioned on 5/11 has been solved. Both of the formulas are correct. However, he found that the central scattering angle jumped within one momentum setting for more than 3 deg. Chao mentioned that his calculation result does not show this behavior and they will discuss this offline. More details can be seen in his slides here.

5/18/2016

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

Feature Presentations:

• Chao

Gave an update of the acceptance study. He used the elastic scattering data to calibrate the resolution of the simulation. He found that the simulation package does not treat the resolution of the beam position properly. Thus the simulation package is updated to generate the events according to the beam profile. With this new update, the resolution of the simulation agrees with the data. More details can be seen in his slides here.

5/11/2016

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

Feature Presentations:

• Toby

Gave an update of the scattering angle calculation. He used two formulas from Pengjia and Chao to calculate the scattering angle and suggests that the results do not agree. People suggests that this two methods are equivalent and we should just use one of them. More details can be seen in his slides here.

• Ryan

Gave an update of his study of the scattering angle dependence of the cross-section. He used the radiated Bosted model and calculated the cross-sections with three different scattering angle. And the results shows ~20% difference. More details can be seen in his slides here.

• Jie

Gave an update on his study of the yield drift problem. He is still working together with Pengjia to correct the beam current dependence of the beam position. He summarized the beam current distribution for all production runs and found that ~90% of our data was taken with current less than 50 nA, where the beam position need to be corrected. He also studied the "sudden jump" of the beam position which means that the BPMA and BPMB readout did not changed much but the reported beam position changed a lot. It probably could be explained by the pedestal change but still need more study. More details can be seen in his slides here.

4/20/2016

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

Feature Presentations:

• Ryan

Gave an final update of the nitrogen cross-section study of the saGDH experiment. The radiative correction is done and the uncertainty carry-over from the elastic tail analysis is 1.5%. The radiative correction is calculated in two different way: the classic unfolding and the ratio of un-radiated and radiated Bosted model. He also did a bin center correction and compared the result with Vince's calculation. Two methods agrees at a 1-2% level. The radiative corrected cross-section for each kinematics setting is summarized in his slides and he will prepare a tech note for the analysis. More details can be seen in his slides here.

4/13/2016

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

Feature Presentations:

• Jie

Gave an update on his study of the yield drift problem. Last time he showed some plots which indicates that the beam position might not be accurate and he did some study on this problem. He found out that the BPM readout shows some linear relations with the beam current. After carefully check the data, it seems that only the BPM B have this correlation. And this problem could be found in all beam energy settings. The uncertainty of beam position is very large if this problem is not corrected. More details can be seen in his slides here.

• Ryan

Gave an correction to his presentation on last week. He mentioned there was a mistake when he compared the formulation for the full internal bremsstrahlung tail and the angle-peaking approximation. And the results agree after the mistake was corrected. More details can be seen in his slides here.

4/6/2016

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

Feature Presentations:

• Ryan

Gave an update on his radiative correction study. He already studied the uncertainty for the elastic tail and he continued his study with the inelastic radiative correction. He explained how the angle approximation was applied in the internal bremsstrahlung. There is an equivalent correction in the angel approximation which is dropping the soft photons compare with doing a full integration. Difference between these two calculation is 5-10% for proton. He is still working on applying the calculation to other nuclei like Nitrogen. More details can be seen in his slides here.

• Toby

Gave an update on the his calculation of the asymmetry and cross-section. He applied the dilution factor calculated from the data to the asymmetry calculation. On the other side, he also applied the radiative correction factor calculated from the MAID model to the asymmetry calculation. He then applied the same factors to the cross-section calculation and got the cross-section and cross-section differences. The dilution seems not continuous and JP suggests to do a deeper study for each momentum in the longitudinal setting to understand what is the reason, for example the yield problem studied by Jie. 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.

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