Jul 31/24 PionLT/KaonLT Analysis Meeting Notes ---------------------------------------------- (Notes by GH) 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 - Garth Huber, Nacer Hamdi, Ali Usman, Alicia Postuma, Nathan Heinrich, Muhammad Junaid, Vijay Kumar, Zach Sullivan Virginia - Richard Trotta Ohio - Julie Roche CUA - Tanja Horn JLab - Dave Gaskell (last half) Nathan & Zach ------------- - Zach had a problem w/ python script in ALMA9. Nathan and Junaid have not been able to fix it - Junaid thinks there has been a change in python syntax, but can't figure it out, stuck for now - *NB* Richard will take a look, probably an incompatibility between versions of python and pyroot that needs to be fixed - the same problem is likely to also affect Richard's analysis, so this is a high priority for fixiing Junaid ------ PionLT Heep Study - 9 beam energies - investigating two issues 1) some EM distributions are broad - for all 2021 data, EM peak is sharp - for all 2022 data, EM peak is broader - checked raster parameters, there are multiple raster calibs for 2021, but only one for 2022 that Mark Jones posted, based on run 14809 @ 7.950 GeV - no raster issues were noted for 2022 run, so presumably a single raster calib is sufficient - GH and Richard: *NB* try looking at EM versus raster_x, raster_y - if there is a problem, EM will be correlated (tilted line) with respect to these variables - the plots that Richard recommends are: 2D: (S)HMS EM vs delta (S)HMS PM vs delta SHMS delta vs HMS delta raster_x/y vs PM/EM raster_x vs raster_y 1D: BPM target x/y 2) calculation of Heep COIN error - checked error calculations, was using weighted SIMC yield instead of raw SIMC counts in the error calculation - this makes a huge difference, MC errors now much smaller Nacer ----- Heep error checks - worked with Junaid, found the problem by checking numbers step-by-step Comparing Heep models in progress, to establish uncertainty in the MC prediction Comparison of Nacer and Richard Heep yield ratios - it is important that we understand why the Heep ratios deviate from unity, and perhaps understanding the difference between Nacer and Richard's ratios will shed some light on this - *NB* Richard will re-run some scripts to recheck and understand the discrepancy Alicia ------ BSA paper update - B-G Yu happy with latest changes, paper is ready for submission - filled out fields on PRL server, will be submitted later today Ali --- piDelta BSA analysis - Garth asked to show BSA plots for all settings Q2=2.1, W=2.95 - 2 t-bins, data very smoothly follow sine-curve fits - BSA amplitude ~0.12, small errors Julie: *NB* can you please make residual plots of data-fit? The fit actually looks too good, Chi-square<1 Q2=3.0, W=3.14, 2 t-bins - errors a bit lager, fluctuation about sine curve gives Chi-square<1 Q2=3.0, W=2.32, 1 t-bin - right SHMS setting had mroe stats than left, so errors vary with phi-bin Q2=4.4, W=2.74, 1 t-bin - errors a bit bigger, BSA amplitude ~0.15 Q2=5.5, W=3.02, 1 t-bin - errors bigger, Chi-square clearly <1 for ALL plots - errors are statistical only, systematics not yet included Julie: *NB* can you please send me exactly how you calculate your error bars? - maybe your errors are over-estimated, do not follow 2/3-rule Next steps - work on systematic uncertainties in progress - syst unc due to 2 types of fits, 2 studies - syst unc due to cut-dependence, 2 studies Richard ------- KaonLT LT-iteration fitting - updated sigT functional form - added t-dependence, t-trend of Ratios more uniform now, but more iterations needed as Ratios ~0.4 - Tanja found an old Fpi-1 log entry by Jochen Volmer, dated Mar 16/2000: - he tried a functional form for sigT of the type: a+b*(W-Wc)+c*(Q2-Q2c)+d*(W-Wc)*(Q2-Q2c) - this seems like a very nice function that could describe the variation of the cross section across the diamond, where the diamond center is at (Q2c,Wc) - tried fitting it as sig_UNS at high,low epsilon, just to see what results - b & c terms have significant t-dependence, d more constant - curiously, b & c have opposite t-dependences, but they're in orthogonal directions on the diamond, so not sure if this results in cancellation or not - looks promising, GH suggests to try this form for sigL and sigT, perhaps could use a linear t-dependence for b & c, given their strong t-dependence Vijay ----- Low Q2 PionLT volume cut systematic uncertainties for L,T,LT,TT - varied delta, xptar, yptar by +/-10%, 6 cut changes in total per spectrometer - SHMS-delta - no variation in sigL,sigT - SHMS-xptar,yptar - sigL varies 0.1-0.8%, depending on t-bin - sigT varies 0.1-1.2% - HMS-xptar,yptar - variations are similarly small - HMS-delta - variations are much larger, sigL 28-90%, sigT 40-90% - *NB* we need to better understand what is going on here, unexpected sensitivity Dave: *NB* you might need to increase the SIMC event generation limits - plot delta,xptar,yptar for +10% limits and check - another thing to keep in mid is that the HMS delta matrix elements are less understood past 8%, so the +10% cut is past the well-understood acceptance - 7.2% (-10%) cut is more reasonable, but your results look similar for 8.8% - *NB* suggest to look at Vladis Tvaskis' PhD thesis: - Vladis and Henk found that a small correction to HMS-delta was necessary, affected things at the few percent level - if this correction is not implemented in the analysis, then we should look at adding it - *NB* please make plots of focal plane and physics variables for delta-10% cut, so we can see if there are any large discrepancies between them that could explain the unexpected variation Next Meetings -------------- - Note the special time: Wed Aug 7 @ 15:00 Eastern/13:00 Regina - KaonLT will go first - Dave and Julie can't attend then - Garth will be at Exclusive Reactions meeting @ Trento, will connect from hotel room - Thur Aug 15 @ 15:00 Eastern/13:00 Regina - Dave will take notes - PionLT will go first