Feb 22/24 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 - Nathan Heinrich, Garth Huber, Ali Usman, Alicia Postuma,
Muhammad Junaid, Nacer Hamdi
CSULA - Konrad Aniol
CUA - Richard Trotta, Tanja Horn
York - Stephen Kay
FIU - Pete Markowitz
Nathan
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Writing Lumi analysis script for PionLT
- modifying script from Richard, which always assumed an active HMS and SHMS
trigger for each run, as some PionLT Lumi scans were single arm only
- had to make similar edits earlier for CoinLumi script, so confident of the
needed changes
- edits made, still testing
Script for plots for SHMS NIM paper
- started to modify old plotting script
- looked briefly so far at the draft NIM paper text
- once the plotting code has been run, will look up needed details for the
paper
Junaid
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PionLT efficiency studies
- investigating outlier runs identified last week, about 30 runs in total
- will make some decisions soon on which runs to discard
- then will post efficiency slides on RedMine
Ali
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SIMC resolution study
- on hold until Alicia finishes HMS delta-correction study
Setting up for pi+n LT-analysis
- replayed 3 of 5 settings so far (both epsilons)
- of these, analysis completed for 2 of 3 settings
- will give Richard clean pi+n data for subtraction
- updated SIMC w/ physics_iterate.f model
- compared to Vijay's code, almost identical except for different Q2-settings
- looking at Richard's LT-sep scripts, hoping to have some initial ratios soon
Info re HGC cut issue
- no HGC cut intended to be used for pi+n analysis, get a small K+L leakage,
but in MM region well above pi+n
- this means pi+n analysis will also not need an HGC efficiency to be applied
- on the other hand, pi+Delta0 region is affected by K+L leakage, and will
need an HGC cut as well as an HGC efficiency to be applied
- the pi+ sample for Richard will not have an HGC cut applied
- will give skimmed ROOT files w/o HGC cut to RT, he will have to apply the
HGC cut before subtracting pi+ leakage sample from K+ data
Richard
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Comparing SIMC model to preliminary data
- looked at 4 of 6 settings (including Q2=0.5)
- Q2=0.5 has lots of issues that he will flag for Nacer to eventually look at
- standard.kinematics issues:
- need to confirm that CoinTime offset is set correctly for EVERY run
- SHMS_RF_Offset was also not set for some low Q2 runs
Initial look at Q2=2.115, W=2.95
- all LT, TT terms set to zero for now in model
- sigL model: adjusted exp(|t|-0.2) factor to exp(|t|+0.2), seems to give more
stable ratios vs t
- sigT model: compared p5+p6*log(Q2) with alternative p5*log(Q2)+p6/Q4
- also compared to Tanja's global K+ analysis in PRC 85, 018202 (2012)
- checked W-factor and sigT models in this paper
- W dependence: tried changing W-factor=1/(W2-Mp2)^2 to 1/(W2-Mp2)^3
- Tanja's paper has the power as 2.5
- when changing the W-factor, found that the sig_UNS expt error bars changed
a lot, which should have not happened
- this indicates a coding error that needs fixing
- then tried sigT=p5/(1+p6*Q2) and old W-factor
- manually changing p5 from 120 to 25 gave better ratios
- doing things by hand right now, instead of using MINUIT to get new params
Initial look at Q2=3.0, W=3.4
- same procedure, changing sigT and sigL factors
- lowering sigT p5 param improves ratios, just as at Q2=2.115
- *WARNING* data have NO MM-cut applied at all, not only do the exp yields
contain pi+ and proton leakthrough, they also include all K+ contributions
from inclusive spectrum above Lambda peak
- right, now sees a weird phi Left-Right asymmetry in the data
- the experimental yields will CHANGE SIGNIFICANTLY once Richard has a clean
sample
- Ali offers to generate for Richard also a clean proton sample for subtraction
Initial look at Q2=3.0, W=2.32
- looked at using W-factor with ^3 exponent
- getting negative sigL for lowest -t bin, CAVEATS in data as above
Compared initial results vs x_B
- early indications that a systematic change in the model vs x_B will be
needed, will be interesting if this holds up in more thorough analysis
GH: as a reminder, we will eventually have to look again at the residual
Q2-dependence of the Heep-Coin ratios, and resolve this issue before we can
finalize the data and publish
- this should happen after Richard graduates
Alicia
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Implementing HMS delta-correction, hsdelta_NEW=hsdelta-p0*hsxpfp
- took MM calc from Richard's reconstruction script and implemented calc for
data
- as a check, compared new MM calc w/p0=0 to old MM calc
- overall very similar, but a slight difference between them
- plot difference in #events vs Mx, most pi+n events within +/-2 MeV compared
to old MM calc
- best guess is that there is some rounding error difference in the HMS
momentum calc compared to hcana when applying offsets
- GH: as a coding check, can try comparing old and new MM w/o offset
- then applied Dave's p0 values and compared the old-new data
- MM gets wider instead of narrower, something still seems wrong
- GH: suggest to make a plot of hsdelta_NEW vs hsxpfp to see what kind of
correlation you get, should be a straight vertical band if applied
correctly
- Alicia will send her script to Richard for review
Nacer
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Low Q2 KaonLT calibs
- finished DC and Hodo timewalk calcs
- pull request to GitHub was accepted
- did a full replay, including all of Ali and Richard's improvements
- plot of EDTM vs Coin_trig_rate
- sees sharp drop off above 2.7kHz trig rate, as expected, due to buffered
mode data acquisition (good news)
- plot of COIN_CPULT vs COIN_trig_rate
- similar behavior, looks good
- plots of HMS(e), SHMS(pi) SING_TRK_Eff vs S1X hodo rate
- no HMS outliers
- a few SHMS outliers that need investigation
To Do:
- check other plots
- move to K+ PID
- also should get Lumi scripts from Richard and look at Low-Q2 Lumi scans
Next Meeting
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- Thur Feb 29 @ 15:00 Eastern/14:00 Regina
- KaonLT will go first