July 17/25 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, Muhammad Junaid, Ivan Zhenchuk, Nathan Heinrich, Nacer Hamdi, Alicia Postuma FIU - Pete Markowitz JLab - Dave Gaskell Virginia - Richard Trotta Ohio - Julie Roche CUA - Tanja Horn Nathan ------ Diagnosing CT shift vs HMSxfp - checked if the timing cuts make sense by looking at T.coin.pTRIG4_ROC1_RawTime, etc., comparing versions w/ and w/o cuts - two main peaks are seen, puzzled by their origin - went through all timing cut parameters one by one, comparing online version (w/ no shift) to offline version (w/shift), doing 500k replays for each - changed adc offset, changed set of triggers used to calculate CT t_coin_trignames changed from pTRIG4(HMS-ELREAL) to pTRIG3(HMS-3/4) - now understands why the offset changed, ELREAL to 3/4 have different cable lengths so the CT value has to be different - can reproduce shift or no shift, and changed offset - still need to change from pTRIG4_ROC1,2 to pTRIG3_ROC1,2 and TDC coin windows back to online version - will have to change time windows accordingly - changed all windows all at once, still need to identify exactly which cut is causing the problem, likely it's related to pTRIG3,4 change Next step will be to determine the Coin Blocking correction - will look at CTime.ePiCoinTime_ROC1 - will compare the contribution of the shoulders in these plots to the good reals and randoms region - *NB* Dave: it will be easier to see the blocked events in the uncorrected Raw CT, rather than the one with pathlength corrections added - try to see if it looks clearer - expecting you will see a time block of main coin events, and a separate time block of blocked coincidences - *NB* Garth: suggest to look at plots for runs with high and low rates, the low rate one should have minimal coin blocking that grows with rate Junaid ------ PionLT LT-separations - completed the SIMC weight recalculation script - met with Richard on Tuesday about it - testing the script now - shows output of 3 events, identical between SIMC and weight script - would like Nacer also to check the script Next step - will rerun SIMC w/new params for 1 setting and compare output to SIMC w/old params and weight recalc - should have results of first few iterations by next week Nacer ----- KaonLT Low Q2 LT-separations - zeroth iteration w/Tanja's functions and thesis params give R~0.35 - investigated fit param sensitivity to initial values in fit - did both ROOTfit and pythonfit - pythonfit is more sensitive to initial params, ROOTfit less sensitive - data & MC comparo plots - more deiations w/Tanja model compared to Koltenuk model Richard ------- KaonLT LT-separations - using simpler functional forms shown last week - changed Lambeda MM selection cut from 1.08sig_hieps for some t-phi bins, but the diference is getting smaller now - first priorities will be to finish Q2=3.0,W=2.32, Q2=4.4, 5.5 - still planning on a full data replay in August Alicia ------ u-channel analysis - finding strategies to fit large bkd for MMp>1 GeV - two options under consideration are modifying Ambrozewicz Xphasespace model and Pythia generator - Xphasespace - Bill had suggested to modify this to include 3-pion phasespace - reviewed Ambrozewicz thesis - it is a uniform sampling of MX