Aug 17/23 PionLT/KaonLT Analysis Meeting Notes
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(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
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Regina - Garth Huber, Nathan Heinrich, Nacer Hamdi, Alicia Postuma,
Muhammad Junaid, Vijay Kumar
JLab - Dave Gaskell
CUA - Richard Trotta
CSULA - Konrad Aniol
Nathan Updates
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HGCer Calib Update
- parameter equation in standard.database
- changes pushed to GitHub
- comparison w/ online HGC plots
- NPE distribution goes much higher now, particularly for last runs of
experiment, where gain drop was significant
- will post slides on calib after final set of runs is completed on ifarm
Working on standard.kinematics
Junaid Updates
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HMS Calorimeter Calib
- working on 9.177 GeV (2021) data
- marged Nathan's changes
- calibrating once a shift now
- DG: question on whether it is needed to calibrate this frequently
- MJ: sees shifts after 2-3 days, so need fairly often
GH: please have a discussion with Nathan, and come up with a plan on how many
runs need to be calibrated, and how long do you expect it to take
- concerned that MJ will feel stuck working on calibrations for a very long
time, so we should see if we can finish by Labor Day, if possible
Richard Updates
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Changes to mc_shms_hut.f for calorimeter edge cut
- it was commented out in RT's version, but NOT commented out in SIMC master
- DG: these cuts can be done either in a standalone script, or in SIMC, it's a
matter of what you prefer
Aerogel tray cuts now implemented in recon_hcana script
Implementing HGC hole cut
- will discuss this more w/ Ali after he's back
Kinematics averaging code is now simpler, replicating old Fortran code
- now just taking average kinematics per t-bin
Will give an update on Lumi scans status next week
Vijay Updates
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Confirmed that calorimeter edge cut is NOT commented out in his SIMC
Target boiling corrections work in progress
- hoping to show some plots next week
Alicia Updates
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Follow up from Portia's work on piDelta BSA
- Portia did not have weighted SIMC plots, adding weights improved things a lot
- also a small error in phi conversion between Data & SIMC corrected
- No Dummy subtractions yet (but Randoms are subtracted)
- Using SIDIS & piDelta MC output for MM-distribution shape
- fit to data looks very good (Q2=2.115)
- pi+n radiative tail also not yet included
- plot including radiative tail shows a significant contribution underneath
piDelta peak
- Preliminary BSA plot (Center only)
- integrated fitted piDelta MC to data
- expecting a large systematic uncertainty from the fit
- only one t-bin so far, possibly the Q2=2.115 can have two t-bins
- DG: HERMES had only one t-bin, but they removed the -t_min region (where
asymmetry is small) so that the remaining region had a larger BSA
pi+n Binning
- Q2=5.5: decided to have 4 t-bins rather than 5
- trying different phi-bin options: 9, 11, 13 bins
- DG: should get same asymmetry for all choices of phi-bins, provided there
are sufficient bins to fit the asymmetry moments
- in general, more bins are better
- 13 phi-bins looks good for Q2=5.5
- GH: please make a table of fitting results & errors vs #phi bins, so we can
check fit stability and trends
- DG: a little worried about the dependence on #phi bins, suggests a MC study
to see if there are any issues, such as e.g. if 9 phi-bins are sufficient
- Q2=4.4: 5 t-bins seems fine
- results with both 13, 15 phi-bins look okay
- 13 bins has a bit more wiggles
- Q2=3, W=2.32: 7 t-bins
- Q2=3, W=3.14: 7 t-bins
- this set has very good statistics
- Q2=2.115: 8 t-bins
- first t-bin has nearly zero asymmetry, very close to -t_min
- fit with A,B,C a bit weird, looks reminiscent of a capacitor breakdown
plot
- NG: there should be a way to tell ROOT the bins have a width, that
might get rid of the weird fits
- Nacer: has a small function that AP can try
BSA Error Analysis
- tried to re-derive error equation in S.Diehl's paper
- Diehl's eqn seems to be based on the approximation
Y+ \sim Y- which leads to Y+^2 + Y-^2 \sim 2Y+Y-
- DG confirms this is a common choice in PV experiments
- Alicia's formula has no approximations, is exact
- approximate formula leads to an under-estimation of errors
- difference between exact formula and approximate formula is small in most
cases, but the deviation grows for points where the BSA > 0.1
- Diehl BSA < 0.1, so difference not significant for those data
- we will use Alicia's formula, since it is more accurate
Next Meeting
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- Thur Aug 24 @ 16:00 Eastern/14:00 Regina/13:00 Pacific
- KaonLT will go first