May 22/25 PionLT/KaonLT Analysis Meeting Notes ---------------------------------------------- (Notes by GH) Today: KaonLT 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, Muhammad Junaid, Ivan Zhenchuk, Alicia Postuma, Ali Usman, Nacer Hamdi, Nathan Heinrich, Vijay Kumar Ohio - Julie Roche JMU - Ioana Niculescu FIU - Pete Markowitz JLab - Dave Gaskell Virginia - Richard Trotta Alicia ------ u-channel simulations - as previously reported, Pythia seems encouraging as a way to simulate background processes underneath the omega peak - the plan is to output Pythia events to a file and then read these into SIMC - struggling with reading Pythia events, will meet separately with GH Nacer ----- KaonLT Q2=0.50 LT-sep - all kinematic tables and yield files now generated for all t-phi bins - plots of Data/MC ratios vs phi for each t-bin show some anomalous zero entries - investigating the outliers, about half of them have been addressed so far - making plots of MM for each t-phi bin to investigate further (as suggested by Richard last week) - calc_xsect.f - the routine used to calculate unseparated cross sections from the model and Data/MC ratios for each t-phi bin - has version from GH, still trying to understand the code Vijay ----- pion absorption factor for Low Q2 PionLT - working with Alicia's Geant4 code, making comparison plots for pions at 2,3 GeV/c momentum to check against her reference plots - plots of calorimeter output look good - HGC NPE and Aerogel NPE plots are empty, asked Alicia for some suggestions Richard ------- KaonLT high Q2 LT-sep - Q2=5.5 still running on ifarm - in the meantime, looking at Q2=3.0, W=3.14 - high epsilon Data/MC ratios near 1, but with oscillations of +/- 0.5 - low epsilon ratios good for lowest t-bin, but trend quite a bit higher (~2) to highest t-bin - GH: this indicates the t-dependence of sigT (primarily) is not correct - comparison of Focal Plane variables between Data and MC shows that the model is quite far off from the data, shapes not in agreement - expects that some change in functional form will be needed (particularly for sigT) - Next steps: - will concentrate first on Q2=3,W=2.32, Q2=4.4, Q2=5.5 so we have a good Q2-scan at fixed xB before tackling Q2=2.115, Q2=3,W=3.14 Ali --- pi+Delta0 BSA finer t-bins - MM shape study for rebinned data is complete - has extracted yields for finer binned data - has recalculated kinematics for rebinned data - in the process of making asymmetry plots - thesis defense is on May 30 Nathan ------ PionLT anomalous deadtime investigations - still looking into hodoscope timing issue identified by Dave on May 8 - looking to rerun calibration script to see if it fixes the time shift issue - ran into problems with the calibration script - when the OS was updated, a C++ operator was deprecated, which broke fit_hoco_calib.c - problem has been fixed and will push soon to GitHub - the two shifted runs identified on May 8 are from different run periods, it seems odd that both broke the same way - the most likely explanation is that a timing offset has changed - rate dependent yield checks - removed weird Python integral function identified last week - Carbon Lumi scan generally looks good, but there is an outlier that will be investigated - the next step after that will be the LH2 boiling scan Junaid ------ PionLT Q2=3.85, W=2.62 LT-sep - kinematic variables have been calculated for each t-bin - Data/MC ratios per t-phi bin have been tabulated - SHMS settings are combined via error weighted average of ratios - doing some by-hand checks to make sure everything is working correctly - also has Garth's calc_xsect.f and trying to understand the code Ivan ---- KaonLT Low Q2 BSA analysis - trying to replicate Nacer's PID and pion leakage subtraction studies - for now, using Cherenkov PID cuts - will switch to RF cuts, the same as Nacer - Nacer: suggests to make a CoinTime plot with cut on Lambda/Sigma MM, to make the K+ CT peak more clear, otherwise it's buried by the pi+ coincidence - MM plot pi+ leakthrough and randoms subtracted - pi+n peak from clean sample and physics sample have slightly different shape, which gives a small number of negative counts on one side of difference and a positve number on the other, with the two parts hopefully canceling (this is not checked yet) - Nacer did not see this, so hopefully the effect will go away when switching to RF cuts - HGC cuts - interestingly, when applying NPE cut, the pi+Delta0 peak is removed but not the pi+n in the MM spectrum - Garth recalls that we saw this in the online data, not all of the SHMS focal plane has pions above Cherenkov threshold, the +delta part was above threshold and the -delta part was below threshold - this can be verified by plotting HGC_NPE vs SHMS_delta - since pi+Delta events have larger MM, they will be preferentially at lower delta than pi+n events Next Meeting ------------- - Thur May 29 @ 15:30 Eastern/13:30 Regina - PionLT will go first - Alicia will plan to show her draft CAP Congress slides