Nov 30/23 PionLT/KaonLT Analysis Meeting Notes ---------------------------------------------- (Notes by GH & AH) 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 - Muhammad Junaid, Garth Huber, Ali Usman, Alicia Postuma, Nathan Heinrich, Vijay Kumar, Nacer Hamdi JLab - Dave Gaskell CUA - Richard Trotta CSULA - Konrad Aniol Nathan ------ TCoin Reference time cuts to improve event selection before feeding into HCANA. - Showed ElReal coincidence time for trigger TRIG1 ROC1 and ROC2, with lower edge cut on the time RED: multiplicity=1 cut applied (signal peak) BLUE: no multiplicity cut (flat bkg) - only 2 sets of cuts needed: pTRIG5 = (ELREAL_hms X 3/4_shms) pTRIG6 = (3/4_hms X 3/4 shms) - looked at ~20 runs taken at various times to check cut stability, which appeared to be good - Nacer: what would be the effect of having a wider window? NH: hcana takes the first time after the cut. If an event had two hits, a good one in the peak, but a bad hit coming earlier before the peak, a wider cut would allow the bad hit to be used instead of the good hit. This means we would actually lose the event if we had a wider cut - the point is that a wider cut does not necessarily mean more events. We need the optimal cut to get as many good events as possible. Plan for next 2 weeks: - by next Tuesday: will have new TCoin reference time cuts implemented - then will run a full replay of PionLT data - will do a quick comparo of Heep vs SIMC distributions so GH can work on PionLT offsets and compare them to KaonLT offsets - GH: it will be worthwhile to see if any report file changes are needed before doing the full replay - NH will discuss this w/Ali - also need to be sure helicity info is enabled in the reply - DG: and also enable EPICS trees so that magnet set points can be checked Junaid ------ Recheck of drift chamber calibration after hodoscope calibs - all LD- data needed to be recalibrated, changes particularly large for 2022 - no changes needed for positive SHMS polarity runs Plan for next 2 weeks: - as Nathan, full replay of PionLT data - then will work on tracking effs - meeting w/Ali next Monday - it would be good if Ali/Richard could find some old slides for Junaid to review Richard ------- Heep offsets - presented final results for all 5 KaonLT energies - Ali found that 8.2 GeV Heep polarities were not inverted after all HMS=electrons, SHMS=protons, as usual - Richard's analysis only had them flipped for dummy target data, but it affects how the 8.2 Heep data were interpreted for the offsets - final offsets (units of 0.1%, 1mrad) in-plane: dthe=1.0 dthp=1.1 oop: dphe=2.51 dphp=-0.11 dpp=-2.0 dpe=-1.0 (3.8, 4.9, 6.2 GeV), -2.0 (8.2), -2.8 (10.6) de varies for beam energies, but generally small - Improved variables after offsets, except Emiss (trade off between E_miss and W) BLUE=SIMC, Red=Data - 10.6 GeV: W gets worse, EM better - offset chosen to get both to be similar, not prioritize one over the other - DG and GH agree this seems a sensible approach Next steps: - goal is to rerun Heep analysis to double check all is okay after Ali's analysis script changes (to incorporate offsets) - then do full KaonLT replay - will meet w/Ali to discuss uncertainties and efficiencies Ali --- Updating a lot of stuff in LT replay in last 2 weeks - while updating energy offsets in standard.kinematics, the 8.2 GeV Heep setting caught his eye, and he found the polarity discrepancy - the run sheets were wrong in that they had negative polarity for SHMS and positive for HMS, while the reality was the normal configuration - Dave: all magnet set points are recorded in EPICS, one could have compared the set momentum values and look for outliers - in SIDIS analysis, a script was written to do this - please enable EPICS trees in next replay, and he will do a check - 10.6 param files were updated for new TOF tolerance value, to fix beta-CT correlation seen in recent weeks - made sure other KaonLT energies had correct tolerance values - Implemented the Heep offsets in the LT software framework. Plan for next 2 weeks: - Working on DeltaPi beam spin asymmetry analysis - started looking at L,C,R SHMS settings - PhD committee meeting is on Dec 13 Vijay ----- No report, busy on PhD committee report Alicia ------ No report, busy with classes - Once offsets are implemented, will replay 10.6 GeV pion data w/helicity - discussing DeltaPi beam spin asymmetry w/Ali - need to understand how to handle L,R settings where (t,phi) bins have poor statistics - GH happy to discuss this offline. Bill had the same issue in his omega analysis, and included in his scripts some various criteria for whether to exclude a (t,phi) bin or not - Dave: asks if L,C,R will be combined before doing background fitting - GH: No, in that case one is too sensitive to whether the MC properly handles the kinematic variation of the background across the acceptance - much more reliable, but also more tedious, to make MM plots for each (t,phi) bin and fit each one separately, as Bill did in omega analysis - Need discussion on the how to treat the background, especially the sensitivity to phi angle Nacer ----- 3.8 GeV KaonLT, fixing shift in beta_SHMS - looked at hodo time walk correction, looks good, no new calib needed - Re-calibration of Vp signal propagation velocity vs time of walk difference (PMT+, PMT-) for each paddle - SHMS Beta shift is now corrected for one dataset, which is great news - beta dist is noticeably narrower and with peak just below 1 Next steps: - check SHMS Beta for different settings at 3.8GeV, and for 4.9 GeV data as well - issue is first to see whether new 3.8GeV calib works properly for them, without doing more recalibrations - when these are confirmed to be good, then need to recheck DC calibs, will discuss w/ Junaid when he gets there Next Meeting ------------ - Thur Dec 7 @ 15:00 Eastern/14:00 Regina - KaonLT will go first