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Kaon LT Meetings » mtg_26jun11-12.txt

Garth Huber, 06/12/2026 05:06 PM

 
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               June 11-12/26 PionLT/KaonLT Analysis Meeting Notes
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               --------------------------------------------------
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                               (Notes by GH)
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                       This week: KaonLT will go 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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Thursday: Present
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-----------------
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Regina - Garth Huber, Alicia Postuma, Nathan Heinrich, Muhammad Junaid,
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   Dex Yadlowski, Nermin Sadoun
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JLab - Dave Gaskell
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Virginia - Richard Trotta
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CUA - Tanja Horn, Chi Kin Tam
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Alicia
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------
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- presented draft u-channel slides for next Wednesday's Hall A/C talk
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  - plan to have preliminary LT-sep plots for the presentation fell through
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- Dave will send links to other Hall C VCS experiments
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  - Hall C 12 GeV VCS result:
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    https://www.nature.com/articles/s41586-022-05248-1
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    - it is backward angle, but doesn't go all the way to 180 degrees in the
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      center of mass. It seems to focus on the area around ~140 deg
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  - the recent run this year was for the VCS-2 experiment. The proposal for that is at:
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    https://misportal.jlab.org/mis/physics/experiments/viewProposal.cfm?paperId=1102
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    - it has similar theta-cm coverage.
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Chi Kin
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-------
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New KaonLT Q2=3.0 W=2.32 Results
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- Data/MC yield ratios ~0.9-1.25, based on empirical (linear or quadratic) fit
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  of background in Lambda region
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  - fits background left and right of Lambda peak
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  - area underneath Lambda peak is not subtracted
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  - *NB* Garth/Tanja: need to interpolate the background underneath the Lambda
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    from left and right regions and subtract it too
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- plots of Data vs MC for kinematic variables look pretty good
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- sig_uns: sig_loeps very close to sig_hieps
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- L/T results: sigT ~228, sigL ~15, very different than Richard's results which
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  had significant sigL
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  - not unreasonable to assume that high sigL in Richard's results was due to
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    pi+ background leaking into K+ yield
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- yields also differ from Richard's by 2x, this needs more investigation
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Richard
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-------
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KaonLT - looking more carefully at background subtraction
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- investigating Garth's suggestion about using the piDelta region to scale the
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  pion background subtraction in cases where pi+n region is too poorly
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  populated to be reliable
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- considering an event-by-event weight to scale background, based on both pi+n
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  and piDelta regions
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- will run SIMC for pi+Delta0 generation shortly
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  - Garth suggests contacting Ali for his SIMC files, since he already ran this
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    generator for his studies
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Junaid
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------
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- back now from Pakistan
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- working on slides for JLUO and CAP Congress presentations
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Nathan
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------
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PionLT Q2=5.0 setting
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- found an error in SIMC input file, P_shms was too wrong by 2 GeV/c, which
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  could explain anomalous SIMC results for that setting
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PionLT Q2=6.0 W=3.19 setting
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- yields for Left-Center-Right SHMS at same epsilon still don't make sense
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  - Left yield is ~10x Center
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  - High epsilon Right yield is over-subtracted
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- compare to online analysis plots:
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  - Center yield was ~2x Left yield
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  - Low eps, Mid eps, High eps ratios all made sense
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- still investigating why he can't get similar results to online analysis
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  - *NB* Garth suggests to compare charge per run between online and his
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    analysis, to see if that narrows down where the problem might lie
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Friday: Present
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---------------
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Regina - Garth Huber, Nathan Heinrich, Nacer Hamdi, Muhammad Junaid,
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   Dex Yadlowski, Nermin Sadoun
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CUA - Chi Kin Tam
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Virginia - Richard Trotta
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Glasgow - Rachel Montgomery
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JMU - Gabriel Niculescu, Ioana Niculescu
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Nacer
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-----
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KaonLT Q2=0.5 LT-sep
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- working on systematic uncertainty studies
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  - finished Data yields w/ cut variation
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  - still waiting on jobs for SIMC yields w/ cut variation
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  - modifying scripts for syst study, additional plots, etc.
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  - goal is to compute sig_uns for each cut variation
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Gabriel
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-------
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MC Ratio applicability studies
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- Nathan sent a question by eail, to which they responded
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Nermin
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------
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PionLT LD2 Lumi studies
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Scaler yields
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- replayed 7.9 LD2 boiling study, scaler yield
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- combined HMS scaler scans for 6.4, 9.2-1, 9.2-2, 7.9 beam energies
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  - obtain a combined slope of -3.37 +/- 0.35 %/100uA
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- *NB* to obtain the systematic uncertainty, Nathan took the standard deviation
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  of the different scans, and subtracted the statistical uncertainties (in
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  quadrature) to get the remaining systematic
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Tracked yields, 6.4 GeV beam energy, where EDTM should be reliable
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- black points = 6.4 tracked yields up to 80uA
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- blue points = 6.4 scaler yields, where the highest 80uA point was removed
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  because the ELLT will be unreliable since rate was >200kHz
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- combined slope: -3.383 +/- 0.349 %/100uA, so consistent with scaler analysis
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Relative HMS Tracked yields
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- this study needs to use unstable CPULT calculated from equation
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- black points = 6.4 using TLT from EDTM
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- red,green = 9.2-1, 9.2-2 using ELLT*CPULT
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- the different sets are inconsistent @ 2.5% level, indicating there is
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  probably an extra systematic on CPULT of ~2.5%
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Relative SHMS yields
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- needed to keep all runs below 600kHz, if applied same 200kHz criterion as for
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  HMS, there would be too little data remaining for a scan
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- scaler yields
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  black = 6.4
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  red = 9.2-1
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  green = 9.2-2
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  blue = 7.9
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  - the data sets are consistent with a lot of scatter between them, presumably
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    since >200kHz data are used
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  - the 7.9 setting was not used in Nathan's Lumi study because of a
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    mis-communication between himself and Junaid
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Next steps:
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- found a LD2 physics setting where the current varied from 20 to 60uA
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  - will use this as a CoinLumi study
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  - will try applying the boiling correction determined from scalers, as well
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    as other corrections, to see if the yields are flat vs current
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Next Meetings
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-------------
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- Thurs: June 18 @ 13:00 Eastern/11:00 Regina
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  - PionLT will be first
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  - this overlaps the Hypernuclear session in the Hall A/C meeting
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- Fri: June 19 @ 12:00 Eastern/10:00 Regina
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  - we will continue where we left off
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  - not everyone will be available, due to Juneteenth holiday in Virginia
(934-934/934)