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Kaon LT Meetings » mtg_23dec07.txt

Garth Huber, 12/07/2023 09:36 PM

 
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                 Dec 7/23 PionLT/KaonLT Analysis Meeting Notes
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                 ---------------------------------------------
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                            (Notes by GH & AH)
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                     Today: KaonLT 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 - Muhammad Junaid, Garth Huber, Ali Usman, Alicia Postuma, Nacer Hamdi,
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   Nathan Heinrich, Vijay Kumar
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CUA - Richard Trotta, Tanja Horn, Casey Morean
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JLab - Dave Gaskell
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Richard
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-------
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"Final" Heep Offsets
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- The previous computed offsets were wrong due to the usage of an old BPM
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  config file
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- Using the corresponding BPM file, the offsets were updated
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  - lowest 3 beam energies nearly unchanged
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  - 8.2, 10.6 significant changes
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    In units of 0.1%, 1mrad:
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    dPe=-1.0, dPp=-2.0, dThe=1.0, dThp=1.1, dPhie=2.51, dPhip=-0.11
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    dEe varying with beam energy
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- pmx and pmy are improved, trade off between (W, pmz) and (pmx, pmy, E_miss).
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Next steps same as last week.  Expecting to have Heep yield comparisons in 1-2
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weeks.
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Ali
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---
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- Helped Richard with the Heep offsets implementation
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- Ongoing DeltaPi BSA study, planning to show some results next week
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Vijay
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-----
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- had COVID all of the last week
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- working on Luminosity study of summer 2019 data, hope to have initial results
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  to show soon
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- then will look at low energy Heep yield ratios
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Alicia
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------
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- Now that Richard's offsets are finalized, batch script for 10.6 GeV Helicity
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  replay is running
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Discussion about discrepancy between pi+n MC and data MM distributions for
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higher -t bins
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1) treatment of radiative tail in SIMC
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  - DaveG suggested to modify upper limit on Hard Photon radiative limit
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    - this parameter changes how the distribution is calculated for determining
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      whether a given event is within the spectrometer acceptance or not, to
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      save CPU
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    - if event-by-event calculations are done correctly, it should make no
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      difference
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    - indeed, adjusting this limit made no obvious difference
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2) maybe the treatment of MM reconstruction resolution is incorrect in SIMC
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  - this would imply an optics issue in the reconstruction
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  - Dave: Did we check the missing mass resolution dependence with momentum
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    transfer (-t)?
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    - neutron MM peak clearly gets wider for higher -t bins in data, but not
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      SIMC
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    - Dave suggests that Alicia look at MM vs xptar, to see if there is a
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      correlation in the data that needs to be corrected
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    - Alicia: left side of neutron peak is described fine by SIMC, only the
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      right side gets worse
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3) Nacer: maybe it's an issue of missing background?
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- Garth: we could try include non-resonant 2pi production background in SIMC
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- Ali us using SIDIS as well as DeltaPi
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  - SIDIS distribution already includes non-resonant 2pi
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  - Alicia can add this from Portia's script last summer
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  - Garth: the data show a rise at MM=1.08, the 2pi production threshold.
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    Addition of these processes will not fill in the gap between the n peak and
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    MM=1.08, so we will still need to deal with the n peak width issue at
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    higher -t
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4) maybe it's experimental background that needs to be removed?
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  - Alicia showed plots both with and w/o HGC cut
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  - Garth: HGC cut will create an inefficient zone in Focal Plane, but no leak
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    through, as it's a greater-than cut
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  - Alicia: since analyzing only region near n peak, was not planning to
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    include a HGC cut in final analysis
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    - GH: yes that's probably fine, but for a systematics check, we should
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      calculate the asymmetry both with and without the HGC cut
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  - Richard and Alicia will discuss PID cut systematics offline
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Nacer
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-----
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Hodo Time Walk corrections
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- redid 3.8 GeV, GH asked him to check a few runs in 2.9, 4.9 GeV, to be sure
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  all is okay with the new calibs
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- waiting for replays to finish
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Nathan
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------
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- working on the the implementation of Junaid's new DC param files, to build on
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  that for the next full replay
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- fighting GIT on new parameter updates
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  - learned a lot about GIT in the last few days
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  - needed to make ~200 new param files
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  - still have to modify standard.database to point to them, and test
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- it sounds like it would be a good idea to make a new 2024 branch of PionLT
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  and KaonLT after full replay completed
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Junaid
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------
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- Pushed the latest updates for Drift chamber calibration.
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- For the next step, discussed with Ali on the Report Files for the computation
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  of the efficiencies
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  - setting up report files for COIN data
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  - updating cuts for efficiencies, compared to online values
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Next Meeting
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------------
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- Thur Dec 14 @ 15:00 Eastern/14:00 Regina
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  - PionLT will go first
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