Nov 16/23 PionLT/KaonLT Analysis Meeting Notes ---------------------------------------------- (Notes by GH & AH) 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, Ali Usman, Alicia Postuma, Muhammad Junaid, Nathan Heinrich, Vijay Kumar, Nacer Hamdi CUA - Richard Trotta, Tanja Horn, Casey Morean JLab - Dave Gaskell CSULA - Konrad Aniol Richard ------- Optimization of offsets for high beam energy datasets - new study based off GH's older 5_recon offsets, adjusting dPe offset, keeping dPp=-0.1% - dPe has a greater effect on W - then try GH's new offsets, determined with dPp constrained - these work fairly well, but RT adjusts dPe to optimize W, EM overlap - Displayed different variables after including offsets. It seems that some variables get better with some extra variation. - Garth: concerned about optimizing offsets for Heep, which may not work for other data. Better to determine global offsets, for multiple beam energies, so we have some confidence they can be applied to physics data. - RT will try to get 3 sets of offsets: a) 3.8, 4.9, 6.2 GeV b) 8.2 GeV, where the SHMS - HMS spectrometer roles are reversed - fortunately, the SHMS, HMS momentum offsets are similar c) 10.6 GeV, where there may be HMS saturation - Dave: are the optics fine for HMS=6.6 GeV/c setting @ 10.6 GeV? - yes, using Jacob's Matrix Elements, sieve spots look okay - RT is actually using smaller offsets than GH provided for energies other than 10.6 Ali --- Coin Time vs. Beta leakage in 10.6 GeV data - completed the cut-dependence study requested by Tanja/Dave - ~96% efficiency @ 10.6 GeV, >99% for 6.2, 8.2 GeV - Mark sent a write-up on Improved Hodoscope timing and Hit reconstruction algorithm - initial test of ptof_tolerance from 100ns to 2.0ns had no effect - the problem was traced to AU adjusting the wrong cut file - a set of dedicated cut files were used for certain sets of run # - now the smaller tolerance works, the cointime vs beta tails gone, no events lost - the problem seems coming from too loose time window on the hodoscope, our earlier hypothesis that it was related to inverted signal cable was a red herring - Nacer: what is the meaning of this tolerance? RG/Casey: times from all hodoscope hits are propagated to the focal plane, ptof_tolerance is the time window to accept different hits from the hodoscopes when reconstructing an event - 100 ns clearly far too loose, 2ns (a beam bunch spacing) should be good since TOF variations to the hodoscope planes is taken into account in the focal plane projection - fortunately, the ptof_tolerance was already set correctly for the 6.2, 8.2 data, it's a mystery that only the 10.6 GeV data had such a wide window - Garth: we've had repeated issues with things set wrongly in the 10.6 GeV replay. Really hope we have caught them all now. - Ali will update the cut files and make a pull request. A full replay will be submitted after RT has finalized the offsets. Vijay --- OOP offsets - applied 0.99 mrad HMS offset, obtained from GH's fit to just 2.7,3.6,4.6 GeV data - PMY variable is improved for all 3 beam energies - Dave: investigated change in beam angle in different beam periods. The changes were of order ~0.1 mrad, not 1 mrad, so not enough to explain why we need different OOP offsets for different beam periods Alicia ------ No report, was looking into CoinTime issue reported by Ali, and corresponded w/M.Jones - will do a 10.6 GeV pion replay (including helicity info) after RT has finalized offsets Nacer ----- Checking 3.8 GeV hodoscope calibrations after finding shifted beta distribution Nathan ------ CoinTime reference times - Checked multiple T.coin.pTRIG.ROC variables, and looked at different multiplicity cuts - Plot of T.coin.pTRIG1_ROC1_tdcTimeRaw Blue: No cuts, Red: MULTIPLICITY=1 - MarkJ indicated need to separate SINGLES and COIN events, to avoid multiple peaks and allow cut windows to be tightened - will need separate cuts for SINGLES and COIN, different PTRIG - For most variables the timing window cuts are clear - T.coin.pT2_tdcTimeRaw has all events at zero, needs further investigation Junaid ------ - Finished hodoscope calibration, changes pushed today - will post documentation slides on RedMine - Moved to drift chambers calibration. Started with with 2021 data for both HMS and SHMS - Drift distances for different drift chamber planes look better before re-calibration, so it seems the calibration is okay - submitted 40 more jobs for more thorough check Next Meeting ------------ - No meeting next week due to US Thanksgiving - Thur Nov 30 @ 15:00 Eastern/14:00 Regina - PionLT will go first