Apr 2/26 PionLT/KaonLT Analysis Meeting Notes --------------------------------------------- (Notes by GH) Today: PionLT will be discussed first Please remember to post your slides at: https://redmine.jlab.org/projects/kltexp/wiki/Kaon_LT_Meetings Present ------- Regina - Garth Huber, Nermin Sadoun, Muhammad Junaid, Nacer Hamdi, Alicia Postuma Virginia - Richard Trotta CUA - Chi Kin Tam, Tanja Horn, Sameer Jain Ohio - Julie Roche JLab - Dave Gaskell FIU - Pete Markowitz Nermin ------ PionLT LD2 analysis - HMS calorimeter efficiencies - went through Junaid's slides on the efficiency analysis - HMS momentum used for the analysis is same as used for this setting - will use his value - reading up on scientific background of the measurement and the LT-sep method - went through Nathan's Lumi report, will follow up with him on what runs to use for LD2 analysis Nacer ----- KaonLT applying t-shifts - had some issues w/ LT-sep after applying t-shift - changed t-binning, events move to higher -t - used this opportunity to better align t-centers for Lambda, Sigma0 bins - waiting on new replay jobs, had some batch scripting issues - will apply Sameer's CoinBlocking correction after replay is done Richard ------- More on replay batch jobs - there have been some SWIF2 updates - had a meeting w/ Casey, found some ways to make replays faster - designate data output to node instead of cache - then transfer data from node to tape - replays run much faster this way - updated batch submission script at: https://github.com/trottar/lt_analysis/blob/test/run_farm.sh You'll need to follow child scripts, but RT will create a cleaner template version and post to redmine once all replays/apply cuts skim files are complete Junaid ------ - no report, will be focusing on thesis writing, will work in parallel on systematic studies Sameer ------ PionLT Q2=1.6 W=3.08 Low epsilon SHMS center (2022) data - checked stability of Q2 distribution vs run number - fit a Gaussian to distribution to get mean - Tanja: the Q2-distribution is not actually Gaussian, you should not fit the full distribution, either fit just the top of the distribution, or (perhaps even better in this case) just use the histogram mean in the stability study - had a question about 2 runs in this setting - FADC Mode-10 run: these are short runs where Mode-10 data were taken for all detectors, not just Cherenkovs, as a diagnostic check - HMS-3/4 run: HMS-ELREAL is typically used as the pre-trigger - however, since P_HMS is low for this setting, we took additional data so we can determine the ELREAL efficiency at low momentum - don't use either of these as part of physics setting - *NB* it's important to read up on what Mode-10 is, and the trigger configuration - *NB* Sameer will have to use the HMS-3/4 run for the ELREAL efficiency study as part of his physics analysis - this will affect the LT-separation, since it's only an issue for low epsilon data, but not high epsilon, for this setting - HMS, SHMS acceptance cuts - showed plots and asked some questions about what cuts to use - we discussed this also at a Friday meeting a few weeks ago (see the notes) - Junaid: the cuts are based on the region of well understood magnetic optics. For a good introduction to how the optics are calibrated, see Carlos' Thesis "Cross Section Measurements of Deuteron Electro-Disintegration at Very High Recoil Momenta and Large 4-Momentum Transfers (Q2)" https://misportal.jlab.org/sti/publications/16338/attachments/7617/cyero_dissertation.pdf - will use same acceptance cuts as Nermin and Kathleen here Alicia ------ KaonLT u-channel studies - had a productive meeting w/ Bill last week, who suggested: 1) determine Aerogel Efficiency using Heep data to correct for lost protons due to knock-on electrons - Heep will have small pi/K contamination, which is good, but rates will be lower than data, and the efficiency may be rate-dependent 2) constrain rho/omega ratio in MM fits - some variation is expected, but not by an order of magnitude 3) should concentrate more on the MM shape study now, and fine-tune the u-bin borders later 4) add a bin exclusion criterion for #Events near m_omega, in addition to Total #Events in u-phi bin 5) modify u-phi plot to use -u' as radius - u_min is calculated from central kinematics, still gives some events with -u'<0, and of course ROOT cannot plot a negative radius, giving an unrealistic cutoff at the center of the u-phi plot - Garth perefers to use -u+offset as the radius to avoid this issue - modified fitting algorithm - was fitting each u-phi bin independently - based on suggestion (2) now add an intermediate step - first look at u-bin integrated over phi, and determine the overall shape study fit parameters - then fit each u-phi bin separately, using the above values as the starting parameters in the fit - seems to give slightly better results than before - the pion leakthrough seems to have a fairly strong phi-dependence for certain u-bins, which is a bit surprising - not yet including any K leakthrough. A clean K leakthrough sample from data requires pion subtraction, and wants to avoid the systematic error from using pion leakthrough twice - since the main K leakthrough is K+Lambda events, instead will use SIMC (normalized to data) for this channel - will use Tanja's sigfactorized2007 model, some issues with implementation that GH needs to look at - for lowest -u bin, no pion leakthrough used, pion sample is restricted to low MM only and no evidence of pi+n peak in data, distribution is mostly misidentified protons as pi+ - mid -u bin has pi+n peak but doesn't extend much higher in MM - high -u bin extends further in MM, includes pi+Delta0 region - Garth: suggests to write on each u-phi MM plot which exclusion criterion failed if a bin is excluded. Bill did this, and it was an extremely useful diagnostic to see what decision was used to exclude a bin - fitting Pythia to MM data - Bill noticed a discrepancy at the high edge of MM distribution - Garth: this is well past the omega region, suggests to restrict MM range used in fit to exclude the far right edge of distribution - will investigate u-shift to data, to see if it affects the Pythia distribution shape, and improves the agreement w/ data Next steps: - will attempt Richard's event-by-event background weighting (last week) for kinematic comparison plots - will do a new replay w/ Sameer's CoinBlocking correction - modify Garth's t-shift code for u-shift - investigate Aerogel eff w/ Heep data - modify SIMC collimator routine for proton punchthrough - Dave: just replace pion cross section with proton interaction length from PDG Chi Kin ------- KaonLT Q2=3.0 W=3.14 - after applying t-shift, sigL becomes very small in 1st t-bin and sigT becomes large to compensate - not a lot of iterations done though - looked at MM shift again vs t-bin, so see if this is a cause - only see shift (~10 MeV) in high epsilon setting, low epsilon MM shift is near zero - t-dependence of MM shift is small - some discussion of kinematic offsets used - Richard: all spectrometer angle and momentum offsets are global, only the beam energy offsets differ by setting (since there is an uncertainty in the arc-energy-measurement) - also some discussion about magnetic optics offsets - in hms_10p6_GeV.param, Junaid used hphi_offset = 2.8e-4 htheta_offset = 0 - some confusion on whether original 2018 ME are used, or NPS refit of 2018 ME. Part of the issue is that both ME use the same file name, which is BAD practice. Tanja will follow-up with NPS students to have the file name changed - checked HGC hole cut at high and low epsilon - found that x,y axes were reversed, fixed now - found that Vijay's hole cut only worked for low epsilon data, hole cut is too small for high epsilon data - Garth: the issue is that unfortunately the HGC optics were not properly aligned for the high epsilon data. Need to draw a bigger hole cut to account for the enlarged inefficient region - this would have created extra bkd in the high epsilon data, possibly skewing the results Next Meetings ------------------ - Thurs: Apr 9 @ 16:00 Eastern/14:00 Regina - KaonLT will go first - Fri: Apr 10 @ 11:00 Eastern/9:00 Regina - we will continue where we left off