Jun 13/24 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, Vijay Kumar, Ali Usman, Muhammad Junaid, Zach Sullivan JLab - Dave Gaskell FIU - Pete Markowitz Virginia - Richard Trotta CUA - Tanja Horn Vijay ----- MM cut study for low Q2 PionLT data - scanned MM cuts from 0.972 to 0.988 GeV - reanalyzed both data and SIMC with these cuts - reran LTsep script, but did no iterations with model - computed variation in sigL and sigT compared to standard MM cut at 0.980 - results show nearly zero variation in lowest -t bin, rising to ~5% for highest -t bin - calculated RMS of deviations (in absolute units) for all 8 cuts - Dave: if the deviation is systematic between different MM cuts, cannot use the RMS to determine the uncertainty - however, the deviation seems somewhat random, signs flip too, so maybe RMS is okay - no one else has any other suggestions - Vijay will also look at deviations for sigLT and sigTT Next steps - computing RadFlag On/Off systematic - investigate variations in XPtar YPtar cuts Ali --- - spent a lot of time this week making plots for thesis, calibs, efficiencies, PID - completed MM shape study for piDelta BSA, to show results next week - extracted BSA for all settings - will extract LT' - in parallel with this, computing some systematic uncertainties related to MM fitting - variation in neutron fit - MC to data normalization - still has to look at MM cut dep to BSA result - worked w/Nacer last week on Heep analysis, will show some plots next week - at last meeting, Nacer's low Q2 analysis agreed well w/ Richard - worked on 6.2 GeV Heep, also compares well w/ Richard - still looking at Cherenkov efficiency - Junaid's Cherenkov eff (~99.8% vs 97%) helps the discrepancy compared to Ali's eff, but the discrepancy still reamins at 6.2 GeV - Dicussion on things that might address the discrepancy - *NB* Alternate Heep cross section parameterizations are available, e.g. Bill checked multiple Heep parameterizations in his thesis, since the Heep cross sections are less reliable at higher Q2, it would be a god idea to switch parameterization in SIMC and see what the effect is - Dave: is proton absorption included in the Heep analysis? - SIMC does not correct for absorption, only scattering - *NB* need to apply the correction to the Exp data - it could be a 4-5% correction, depending on kinematics - *NB* we had discussed this before, but it was forgotten, Richard and Vijay need to also determine a correction for pi/K absorption and apply it to physics data prior to doing LT-separations - Junaid: Zach applied 3 different Cherenov cuts in his PionLT analysis, gets efficiencies similar to Junaid - need to check if Cherenkov gas pressure changed between KaonLT and PionLT, this could explain the reason why the inefficiency is 10x less for PionLT - Dave: the same gas was used, but the pressure was changed - Burcu identified a light leak in the J/psi data, which caused a large inefficiency issue - the light leak wouldn't have been fixed until much later - *NB* Ali/Zach(?) should search hclog for info on on when the leak was fixed and what gas pressures were set - if we can't explain the discrepancy, we might have to take the difference between them as a systematic, which would be undesirable - if we can explain the discrepancy, then we have a good reason to apply different efficiencies to KaonLT and PionLT data, and the assigned systematic is much lower Richard -------- KaonLT LT-sep iterations - 1st iteration w/ new functional form for Q2=5.5 - 2nd t-bin has highest statistics - has 4 t-bins now, probably should reduce to 3 t-bins - some discussion on what minimum #phi-bins is acceptable - too few phi-bins makes it impossible to separate LT from TT - has 6 phi-bins now, which is also the minimum number that Marco had - Garth: a good way to find out what is the true minimum #phi-bins is to do an MC study similar to what Alicia did, and see what results in a reliable separation of LT, TT for different #bins - *NB* Richard will look into revising #bins, will contact Alicia as well Junaid ------ PionLT Heep coin analysis, 9 settings - rechecked all files, found there was a momentum offset applied to the data prior to determining offsets - renalyzed data w/o offsets, GH generated new offsets - new offsets very similar values to before - checking what sign of offset to apply, tried +/- sign momentum offsets - wrong sign offset gives results nearly identical to correct sign offset, presumably because the applied momentum offset is very small - Garth: the beam energy offset and the momentum offsets should be applied the same way, so you probably should check changing all 3 in the same way Zach ---- Working on PionLT efficiencies for Lumi analysis - will discuss results w/ Nathan before showing Next Meeting ------------- *NOTE THE SPECIAL TIME* - Next meet: Wed June 19 @ 15:00 Eastern/13:00 Regina - PionLT will go first