Apr 17/25 PionLT/KaonLT Analysis Meeting Notes ---------------------------------------------- (Notes by GH) Today: PionLT will be discussed first Present ------- Regina - Garth Huber, Nacer Hamdi, Alicia Postuma, Muhammad Junaid, Nathan Heinrich, Vijay Kumar, Nacer Hamdi JLab - Dave Gaskell FIU - Pete Markowitz Virginia - Richard Trotta CUA - Tanja Horn Junaid ------ Q2=3.85, W=2.62 t-binning - went from 7 to 5 t-bins, covering range 0.16<-t<0.50 - roughly 5k events/bin, up from ~3.8k before - lowest number of counts in a bin is 4315 - will do 15 phi-bins - scripts to calculate yields for each t-phi bin in progress - will give a summary of software framework and Qeff error calculation in a future meeting Nathan ------ PionLT Luminosity Scans - Dave has looked briefly the CoinTime plots, needs to consider them in more detail - arranged a meeting to discuss them with Nathan: Tue Apr 22 @ 15:30 EDT - Tanja reports that NPS found that a small non-linear BCM offset was needed to get their Carbon scans to work out - done by Avnish NPS RG1A scaler lumi analysis (from the NPS elog) - corrected_current=H_BCM4A_Current + corr*sqrt(BCM_rate) where corr is approximately -1.5nA/sqrt(Hz) - applied a rate dependent correcton to Carbon Lumi data and then determined current offset, which is about -200nA, compared to Nathan's ~35nA offset Nacer ----- KaonLT Q2=0.5 LT-sep t-phi binning - solved some problems w/ error propagation in data binning script - wrote SIMC binning scripts, they run well and quickly - Data/MC ratio scripts, kinematics comparison plot scripts in progress - had a very useful meeting with Richard yesterday on his LT-sep framework and SIMC event weighting - will adapt codes to K+ analysis - will present some slides on Yield calculation and Error propagation in a future meeting Vijay ----- Q2=0.50 MM offsets - showed plots for low epsilon: center, Left1, Left2 - resulting offset about 6 MeV gives good agreement between data and MC - Nacer comments on how well SIMC reproduces the pi+n radiative tail - simply matching the highest bin of data and MC, works well for these settings, but in general this method is sensitive to statistical fluctuations and a peak fit is typically used Richard ------- KaonLT Q2=3.0, W=2.32 LT-sep, 4 t-bins - functional forms from Q2=4.4, 5.5 seem okay - Q2-dependence was removed for now to simplify process, only t-dependence, will need to restore Q2-dependence later - Data/MC ratios closer to 1 now for high epsilon, but >2 or higher for low epsilon - kinematic comparison plots overlaying Data and MC look good - some very interesting differences in SHMS-delta between SHMS Center and Left settings, but both are well described by SIMC - preliminary L/T/LT/TT cross sections - L,T have sensible t-dependence, sigL>sigT to middle of t-range - main surprise is that LT,TT are very large, and LT doesn't go to zero as t goes to -t_min - we should consider some systematic studies to do if this holds up Planned next steps: - finish Q2=3.0, W=2.32 - parameterize Q2=2.115, W=2.65 - re-parameterize Q2=3.0, W=3.14 with new functional form - rull SIMC runs with new functions and parameters - full data replay - systematic studies Alicia ------ First look at Q2=3.0, W=3.14 u-channel data - ran SIMC with omega, rho, phi, eta, eta-prime, Xphasespace generators - modified Ali's piDelta shape study code for u-channel shape study - for data, start with aggressive proton cuts to study PID and MM shapes - decided on a CoinTime +/-2.25ns cut for proton selection - RF vs Aerogel: applied a HGC<1.5 npe cut to select protons - preliminary RF<1.7, Aero-NPE<3 cuts reduce pi+ leakthrough a lot, some remains due to HGC hole - RF vs CoinTime: if tight Cherenkov cuts, things are cleaned up a lot - observe that the proton reals peak is not quite at zero, some shift is planned to center peak at zero - MM plot with progressive PID cuts applied - pi+n peak shrinks a lot, much easier to see eta, eta-prime peaks after cuts while they were not evident before cuts - Q2=3.0, W=2.32 center MM plot has much less obvious peaks - *NB* Vijay suggests to tighten the CT cut to see if that helps - Q2=3.0, W=3.14 shape study - sum of Xphasespace and rho MCs do not reproduce shape of continuum distribution at higher MM, unlike Bill's thesis - plot of u vs MM indicates that omega events don't extend below -u<0.6, placing a cut to exclude this region removes a lot of the high MM events - Ali says he does something similar in his piDelta BSA analysis - omega peak doesn't quite line up with MC, will need to adjust MM peak by a few MeV - Lots of discussion about the PID and high MM region - can place a but on HGC hole to reduce pi+ leakthrough - *NB* if so, then should apply same cut to SIMC - Richard says it's straightforward to implement this in recon_hcana - Nacer: suggests to look at events only passing through HGC hole to better understand the leakthrough - Aerogel: applying NPE<3 cut, can look at higher MM region with varying PID cuts - Garth: maybe the extra events at MM>1 GeV are due to proton SIDIS? Hem reports seeing lots of u-channel proton events in pi-SIDIS data - Dave: there is no model for this in SIMC yet, would have to modify pi-SIDIS model accordingly - *NB* Xphasespace model was written by Pawel Ambrozewicz for 4 GeV data, maybe there is some limit in the code? Alicia will look more carefully at the code Ali --- piDelta BSA - new (finer) t-binning finalized - to be efficient, will do some systematic studies in parallel with rebinned shape study - planned systematic studies: - MM shape differences between data and SIMC - new idea after discussion with Garth: tweak bkd fit by ~1 sigma (or whatever seems appropriate based on reasonable fit to data) and extract different asymmetry - wrote new script to do these studies, some debugging underway - plans to show some fitting plots next week Next Meeting ------------- - Thur Apr 24 @ 15:30 Eastern/13:30 Regina - KaonLT will go first ** THIS TIME WILL BE USED AT LEAST UNTIL THE END OF AUGUST **