Mar 12-13/26 PionLT/KaonLT Analysis Meeting Notes ------------------------------------------------- (Notes by GH) Today: KaonLT will be discussed first Thursday: Present ----------------- Regina - Garth Huber, Nathan Heinrich, Alicia Postuma, Nacer Hamdi Virginia - Richard Trotta CUA - Chi Kin Tam, Sameer Jain CSULA - Konrad Aniol JLab - Dave Gaskell Nacer ----- KaonLT Low Q2 cross section checks before systematic studies - KSigma0/KLambda sigT ratios for eventual comparison with Nachtmann's prediction - select t-range in common for both reactions: 0.11->0.14 - t-dependence of both in this region is faiarly flat - used 2 approaches to estimate ratio - directly compare closest t-bin values, no correction for slightly differing Q2,W,t values 1st bin: Lambda -t=0.112 Sigma0 -t=0.111 2nd bin: Lambda -t=0.122 Sigma0 -t=0.128 3rd bin: Lambda -t=0.140 Sigma0 -t=0.139 - compare Lambda data values to model values for Sigma0 at same t - plot of results Red=Data Method Blue=Model Method Red: ~0.25 +/- 0.05 Blue: ~0.2 +/- 0.1 - results are consistent within (large) errors - blue has much bigger errors than red, due to sigificant parameter uncertainties in Sigma0 model - Garth: your Lambda model probably has smaller uncertainties, can try comparing Lambda model to Sigma0 data as a 3rd method - recheck of pi+ leakthrough after background subtraction - checking if steep rise in sigL at low -t is due to pion contamination, pi+ cross section should be largest for high epsilon, low -t bin - MM plots do not indicate any significant evidence of pion contamination, region to left of Lambda peak looks clean - this hypothesis is ruled out, what about other possibilities? - Richard: the effect of the t-shift will be significant since Nacer's t-bins are so narrow, it could be a significant effect - Nacer will investigate this next - CoinTime Blocking - found that Autum2018 ref time cuts are better than Winter2018 cuts Sameer ------ KaonLT CoinTime Blocking - plot of correction for Q2=0.5 vs CoinRate for high and low epsilon data - both show a nice trend vs CoinRate up to 14kHz, values 0.95->0.99 - had a meeting w/Nathan - Nathan: you should use the same time window for a run period, not run-by-run as this leads to over-fitting - i.e. the time window should only change when the DAQ trigger configuration is changed, otherwise combine the runs together to get smaller uncertainties - now has RedMine access, will upload slides for this and previous meetings Richard ------- KaonLT high Q2 LT-sep - implementing t-shift as calculated with Garth's code - looking at how this changed things - taking this opportunity to refine and simplify analysis code - looking also at pion background fits, some of the background uncertainties were estimated incorrectly as too large - Nacer: did you change the t-binning after the t-shift? - No - Garth: it might be needed to change the lower limit of the 1st bin, since events near -tmin will move to higher values of -t - yes, this could be an issue for Q2=3.0 W=2.32 setting Chi Kin ------- - has Garth's t-shift code (it's posted on KaonLT RedMine) - went through how the code worked - Dave: what assumption did you have to make? - Garth: assume no changes to electron beam and HMS, since that would change Q2 - assume all changes are on meson arm, recalculate meson momentum and angle for the shifted MM in order to conserve energy, momentum and then recalculate t Friday: Present --------------- Regina - Garth Huber, Alicia Postuma, Nacer Hamdi, Nathan Heinrich, Muhammad Junaid, Nermin Sadoun JMU - Gabriel Niculescu, Ioana Niculescu Ohio - Julie Roche FIU - Pete Markowitz York - Stephen Kay Glasgow - Rachel Montgomery Virginia - Richard Trotta CUA - Chi Kin Tam JLab - Dave Gaskell (at end) Alicia ------ Q2=3.0 W=3.14 u-channel omega analysis - u (or t?) binning study - forms MM plots of background subtracted omega region - trying 3 u-bins: bin1 0<-u<0.15 bin2 0.15<-u<0.25 bin3 0.25<-u<0.50 - about 2000 omega events in each bin - each u-bin is divided into 8 phi bins Next steps: - Bill had binned in t instead of u, need to have a meeting with him to discuss this - t-binning is not quite equivalent to u-binning, due to relationship between s,t,u - will try finer u-binning at low -u - will try binning in t instead of u (in progress) - will check u-u_true vs t-t_true in SIMC - effect of omega radiative tail in SIMC - Bill had removed all t-phi bins from analysis where the RadOn/RadOff omega ratio was large - will investigate using SIMC and see which bins should be excluded - then need to extend shape study to each (u,phi) bin Gabriel: - there is a statistical method on how to deal with bins where the background subtracted yields are negative - please see https://arxiv.org/abs/physics/9711021 - ROOT can handle this method (asymmetric error bar, with lower limit zero), but need to select the correct option Junaid ------ PionLT Q2=3.85 W=2.62 LTsep - implementing t-shift offsets into analysis scripts - added an extra column to CSV file of corrections to data - will look at t-binning statistics after shift is applied Nathan ------ PionLT Q2=3.85 W=62 cross-checks w/Junaid - got data yields from Junaid for direct comparison - then will do LTsep fit using his fit parameters and compare results - Garth: suggests to start replay of next setting in parallel - expects to start on that next week Nermin ------ PionLT LD- analysis - checked run-dependence of NGC calibration - grouped runs together in different ways, generally consistent - NGC after calibration with PCAL>0.85 and PCAL<0.85 cuts show no significant difference in NPE response - clearly not effective for this setting - Nathan and Garth: we recall low NGC gains early in PionLT and amplifiers were added at some point - Junaid looks at the 2021 Run Status Page: https://hallcweb.jlab.org/wiki/index.php/PionLT_2021_Physics_Status - the Misc Issues for Analysis section has the note: NGC not useful Run < 12066 https://logbooks.jlab.org/entry/3906264 https://logbooks.jlab.org/entry/3906271 - Nermin is looking at runs before this, so it explains why NGC not useful here - Note: there is also the 2022 Run Status Page: https://hallcweb.jlab.org/wiki/index.php/PionLT_2022_Physics_Status *NB* it is important for Nermin and Kathleen to pay attention to what is posted on these pages Rachel ------ PionLT LD+ analysis - Kathleen could not attend, but sent slides that Rachel discussed - SHMS HGC cut - *NB* Garth: if an HGC cut is required to get a clean pion sample, then it is needed to place a cut around the inefficient light collection region neaar the middle of the detector (where the 4 mirrors come together) - need to make a 3D plot of X_hgc, Y_hgc vs NPE - Junaid: shows some example plots showing the inefficient region - Stephen: here are some old histo definition I found quickly, just filled with that X/Y and NPE, that will be useful for Kathleen and Nermin TTreeReaderArray P_hgcer_xAtCer = {fReader, "P.hgcer.xAtCer"}; TTreeReaderArray P_hgcer_yAtCer = {fReader, "P.hgcer.yAtCer"}; h3SHMS_HGC = new TH3F("SHMS_HGC","SHMS HGC Distribution of NPE in X-Y Mirror Plane;X Position (cm);Y Position (cm);NPE",100,-50,50,100,-50,50,100,0.1,35); - SHMS NGC cut - this is for a run number where NGC should be seful - *NB* don't use a cut on pi+ data, can see pi+n MM peak extending to high NPE that would have to be corrected for if you cut them out - pi- runs will likely have no choice but to apply such a cut to remove electrons, in this case you will need to use the corresponding pi+ data to determine (under the assumption that pi+n and pi-p tails are the same) the correction to apply to pi-p data because of the NGC cut - MM plots shown for progressive cuts applied - *NB* Gabriel: you need to apply the most effective cut (removing the most events) first, and the other cuts later - Junaid: first apply acceptance cuts, then CoinTime cut - other cuts after these (RF, Aerogel, HGC) should be applied in different orders, so you can see their effect on the plots, it's difficult to see the effect of a given cut if it's masked by another cut - question about what acceptance cuts to apply - *NB* Nathan: the acceptance cuts are tied to the HMS, SHMS matrix elements that are used - each ME set should indicate the region of reliable magnetic optics, you must use that as the criterion, not the edges of the distributions - the values in the Hall C manual are generic, not specific to the used ME, this is particularly important for settings where the HMS or SHMS have high momentum - Vijay's acceptance cuts should be okay for his data, but his settings were at low momentum, the region of reliable optics can be different at high momentum Next Meetings ------------------ - Thurs: Mar 19 @ 16:00 Eastern/14:00 Regina - PionLT will go first - Fri: Mar 20 @ 11:00 Eastern/9:00 Regina - we will continue where we left off