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Kaon LT Meetings » mtg_26jan22-23.txt

Garth Huber, 01/23/2026 02:25 PM

 
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                 Jan 22-23/26 PionLT/KaonLT Analysis Meeting Notes
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                 -------------------------------------------------
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                                (Notes by GH)
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                Today: Hall C meeting slides will be discussed first
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Thursday: Present
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-----------------
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Regina - Garth Huber, Nermin Sadoun, Nacer Hamdi, Muhammad Junaid,
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   Nathan Heinrich, Alicia Postuma
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CUA - Sameer Jain
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FIU - Pete Markowitz
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Virginia - Richard Trotta
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Nacer
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-----
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Went through his draft slides for Hall C meeting next week
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Junaid
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------
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Went through his draft slides for Hall C meeting next week
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Sameer
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------
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KaonLT CoinBlocking
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- had some questions about EventType=4,7 requirement, which selects COIN events
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  for the analysis
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- applied acceptance cuts from Richard's thesis
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- investigation of Q2=3.0 W=3.14 right SHMS=6.49deg setting, which has a
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  CoinBlock correction not on the same line vs CoinRate as the Center and Left
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  settings.  Left corr=0.94-95, Main group=0.97-1.0
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  - when applying PID cuts, the correction goes from 0.95 to 0.85, in line with
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    the others
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  - Nathan notices that it's not that the low outlier points go up to join the
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    others, as that the others have gone down from near 1 to 0.85-0.9
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  - since the low points are for a SHMS setting which is very close to the
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    beamline, Nathan expects this effect is real and these cuts should not be
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    applied
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  - Nathan does not use PID cuts in his CoinBlock analysis.  Had variations in
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    the CoinBlock correction away from the main trend vs CoinRate, but this
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    turned out to be real, because it make the NormYield vs Rate correlation
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    more flat
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  - Nathan suggests to check the S1X rates for the right SHMS setting compared
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    to center and left.  If they are substantially higher for right than the
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    others, it's probably a real effect
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Friday
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------
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Regina - Garth Huber, Nacer Hamdi, Alicia Postuma, Muhammad Junaid,
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   Nathan Heinrich, Vijay Kumar, Nermin Sadoun
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Virginia - Richard Trotta
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JLab - Dave Gaskell
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JMU - Gabriel Niculescu, Ioana Niculescu
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Glasgow - Kathleen Ramage
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Vijay
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-----
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Went through his draft slides for Hall C meeting next week
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Unfortunately, we did not have a chance to review Chi Kin's slides.  Richard
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will communicate with him on this.
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Richard
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-------
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KaonLT high Q2 analysis
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- redid Q2=3.0 W=2.32 diamond as discussed last week
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  - high epsilon right SHMS setting had a missing bottom right corner, the new
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    (smaller) diamond removes this corner for the other settings too
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 - rechecking t-binning given the smaller diamond
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Nathan
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------
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PionLT Q2=3.85 W=2.62 LT-sep
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- investigated CoinTiming shifts between his analysis and Junaid's
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  - found that some timing offsets were different
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  - also found that Junaid's RFTime cut was different
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  - planning to use Junaid's RFTime cuts, but not planning to use his CoinTime
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    offsets
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  - will make more plots and recheck
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- Junaid will send his latest interation parameters so Nathan can see if he
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  reproduces his sig_UNS as a bug check
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  - t-rebinning (to gain 1 more bin at low -t) will be explored after the cross
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    section checks are done
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  - upper left corner of diamond will also be made slightly tighter, as was
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    discussed in this week's PhD committee meetings
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Kathleen
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--------
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PionLT LD2 analysis
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- still setting up iFarm replays
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- has a copy of Das' PID report and code
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- has set up meetings with Nermin, Wednesdays every other week
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Nermin
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------
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PionLT LD2 PID study Q2=1.60 W=3.08 9.17GeV
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- applied SHMS, HMS acceptance cuts
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- applied very low Cherenkov cuts for now
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- no cuts on SHMS calorimeter for pi+ data
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  - Garth suggests to compare the SHMS calorimeter plots vs MM for pi+ and pi-,
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    the pion distribution is presumably the same for both, but the electron
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    blob will partly obscure the pi- blob
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    - will need to use the pi+ distribution to estimate the #pi- that are
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      removed by the electron cut
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- Alicia comments that with all cuts the #pions in the MM peak goes down a lot
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  - after some discussion, it's probably due to randoms being reduced with
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    CoinTime cut
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- Nathan and Garth suggested to look at random-subtracted MM w/ and w/o RFTime
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  cut, then look to see whether you are losing more background or signal
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  - the right side of the RFTime cut looks a bit tight, suggest to loosen to
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    ~3.5
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 - Gabriel suggests to make plots also of what events fail a cut and see if
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   there is a peak in the MM spectrum for these failed events.  That will be
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   helpful info for tuning the cut
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Next steps
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- will read more about the random subtraction procedure and also look at some
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  pi- data
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Alicia
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------
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KaonLT u-channel shape study
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- setting up framework for shape study for variables other than MM
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  - will apply the MC normalization from MM fit to other variables and compare
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    w/data
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- u-comparison for Q2=3.0 W=3.14 looks good
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  - Garth asks to recheck that recon_hcana calculates u in the same way as in
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    hcana, and not just t
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- Q2, W - a few differences at edges of distribution, which hopefully will be
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  resolved after some iterations
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- epsilon plots shown as well
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Next steps
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- will look at the setting where Pythia is NOT well behaved, to see if the xpfp
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  cut discussed last week screws up the other variables
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Gabriel
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-------
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KaonLT Lambda/Sigma and Lambda/Lambda* ratios
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- GN and IN have come up with a sound procedure for getting the ratios from the
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  data
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  - reminder: beam energy variations are applied to SIMC
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1. Obtain Lambda and Sigma yields for MM cut around peak
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   Y_Sigma_data, Y_Lambda_data
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2. Do same for simulation, both for MM cut around peak and no MM cut
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   and find kLambda kSigma=MM cut efficiency from MC
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3. Use MC ratios method
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   sig_Sigma/sig_Lambda =
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      (Y_Sigma_data  * (1+kSigma) *Y_Lambda_MC*Sigma_Sigma_MC) /
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      (Y_Lambda_data * (1+kLambda)*Y_Sigma_MC *Sigma_Lambda_MC) /
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Next Meetings
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------------------
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- Thurs: Jan 29 @ 16:00 Eastern/15:00 Regina
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  - PionLT will go first
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- Fri: Jan  30 @ 11:00 Eastern/10:00 Regina
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  - we will continue where we left off
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- Richard will make notes for next 2 weeks, while Garth is away
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- will likely cancel Feb 12 meeting, as Regina group will be at conference in
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  Banff, but can still have the meeting on Feb 13
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