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Kaon LT Meetings » mtg_24feb22.txt

Garth Huber, 02/22/2024 06:33 PM

 
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                 Feb 22/24 PionLT/KaonLT Analysis Meeting Notes
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                 ----------------------------------------------
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                                (Notes by GH)
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                     Today: PionLT will be discussed first
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Please remember to post your slides at:
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https://redmine.jlab.org/projects/kltexp/wiki/Kaon_LT_Meetings
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Present
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-------
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Regina - Nathan Heinrich, Garth Huber, Ali Usman, Alicia Postuma,
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   Muhammad Junaid, Nacer Hamdi
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CSULA - Konrad Aniol
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CUA - Richard Trotta, Tanja Horn
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York - Stephen Kay
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FIU - Pete Markowitz
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Nathan
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------
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Writing Lumi analysis script for PionLT
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- modifying script from Richard, which always assumed an active HMS and SHMS
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  trigger for each run, as some PionLT Lumi scans were single arm only
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- had to make similar edits earlier for CoinLumi script, so confident of the
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  needed changes
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- edits made, still testing
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Script for plots for SHMS NIM paper
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- started to modify old plotting script
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- looked briefly so far at the draft NIM paper text
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- once the plotting code has been run, will look up needed details for the
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  paper
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Junaid
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------
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PionLT efficiency studies
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- investigating outlier runs identified last week, about 30 runs in total
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- will make some decisions soon on which runs to discard
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- then will post efficiency slides on RedMine
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Ali
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---
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SIMC resolution study
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- on hold until Alicia finishes HMS delta-correction study
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Setting up for pi+n LT-analysis
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- replayed 3 of 5 settings so far (both epsilons)
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  - of these, analysis completed for 2 of 3 settings
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  - will give Richard clean pi+n data for subtraction
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- updated SIMC w/ physics_iterate.f model
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  - compared to Vijay's code, almost identical except for different Q2-settings
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- looking at Richard's LT-sep scripts, hoping to have some initial ratios soon
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Info re HGC cut issue
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- no HGC cut intended to be used for pi+n analysis, get a small K+L leakage,
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  but in MM region well above pi+n
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  - this means pi+n analysis will also not need an HGC efficiency to be applied
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  - on the other hand, pi+Delta0 region is affected by K+L leakage, and will
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    need an HGC cut as well as an HGC efficiency to be applied
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- the pi+ sample for Richard will not have an HGC cut applied
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  - will give skimmed ROOT files w/o HGC cut to RT, he will have to apply the
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    HGC cut before subtracting pi+ leakage sample from K+ data
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Richard
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-------
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Comparing SIMC model to preliminary data
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- looked at 4 of 6 settings (including Q2=0.5)
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  - Q2=0.5 has lots of issues that he will flag for Nacer to eventually look at
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  - standard.kinematics issues:
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    - need to confirm that CoinTime offset is set correctly for EVERY run
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    - SHMS_RF_Offset was also not set for some low Q2 runs
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Initial look at Q2=2.115, W=2.95
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- all LT, TT terms set to zero for now in model
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- sigL model: adjusted exp(|t|-0.2) factor to exp(|t|+0.2), seems to give more
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  stable ratios vs t
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- sigT model: compared p5+p6*log(Q2) with alternative p5*log(Q2)+p6/Q4
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- also compared to Tanja's global K+ analysis in PRC 85, 018202 (2012)
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  - checked W-factor and sigT models in this paper
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  - W dependence: tried changing W-factor=1/(W2-Mp2)^2 to 1/(W2-Mp2)^3
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    - Tanja's paper has the power as 2.5
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  - when changing the W-factor, found that the sig_UNS expt error bars changed
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    a lot, which should have not happened
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    - this indicates a coding error that needs fixing
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- then tried sigT=p5/(1+p6*Q2) and old W-factor
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  - manually changing p5 from 120 to 25 gave better ratios
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  - doing things by hand right now, instead of using MINUIT to get new params
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Initial look at Q2=3.0, W=3.4
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- same procedure, changing sigT and sigL factors
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- lowering sigT p5 param improves ratios, just as at Q2=2.115
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- *WARNING* data have NO MM-cut applied at all, not only do the exp yields
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  contain pi+ and proton leakthrough, they also include all K+ contributions
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  from inclusive spectrum above Lambda peak
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  - right, now sees a weird phi Left-Right asymmetry in the data
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  - the experimental yields will CHANGE SIGNIFICANTLY once Richard has a clean
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    sample
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- Ali offers to generate for Richard also a clean proton sample for subtraction
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Initial look at Q2=3.0, W=2.32
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- looked at using W-factor with ^3 exponent
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- getting negative sigL for lowest -t bin, CAVEATS in data as above
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Compared initial results vs x_B
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- early indications that a systematic change in the model vs x_B will be
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  needed, will be interesting if this holds up in more thorough analysis
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GH: as a reminder, we will eventually have to look again at the residual
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  Q2-dependence of the Heep-Coin ratios, and resolve this issue before we can
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  finalize the data and publish
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  - this should happen after Richard graduates
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Alicia
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------
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Implementing HMS delta-correction, hsdelta_NEW=hsdelta-p0*hsxpfp
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- took MM calc from Richard's reconstruction script and implemented calc for
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  data
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- as a check, compared new MM calc w/p0=0 to old MM calc
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  - overall very similar, but a slight difference between them
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  - plot difference in #events vs Mx, most pi+n events within +/-2 MeV compared
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    to old MM calc
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- best guess is that there is some rounding error difference in the HMS
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  momentum calc compared to hcana when applying offsets
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  - GH: as a coding check, can try comparing old and new MM w/o offset
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- then applied Dave's p0 values and compared the old-new data
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  - MM gets wider instead of narrower, something still seems wrong
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  - GH: suggest to make a plot of hsdelta_NEW vs hsxpfp to see what kind of
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    correlation you get, should be a straight vertical band if applied
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    correctly
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  - Alicia will send her script to Richard for review
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Nacer
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-----
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Low Q2 KaonLT calibs
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- finished DC and Hodo timewalk calcs
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  - pull request to GitHub was accepted
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- did a full replay, including all of Ali and Richard's improvements
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- plot of EDTM vs Coin_trig_rate
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  - sees sharp drop off above 2.7kHz trig rate, as expected, due to buffered
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    mode data acquisition (good news)
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- plot of COIN_CPULT vs COIN_trig_rate
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  - similar behavior, looks good
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- plots of HMS(e), SHMS(pi) SING_TRK_Eff vs S1X hodo rate
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  - no HMS outliers
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  - a few SHMS outliers that need investigation
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To Do:
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- check other plots
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- move to K+ PID
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- also should get Lumi scripts from Richard and look at Low-Q2 Lumi scans
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Next Meeting
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------------
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- Thur Feb 29 @ 15:00 Eastern/14:00 Regina
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  - KaonLT will go first
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(375-375/412)