Dec 7/23 PionLT/KaonLT Analysis Meeting Notes
                 ---------------------------------------------
                            (Notes by GH & AH)

                     Today: KaonLT 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 - Muhammad Junaid, Garth Huber, Ali Usman, Alicia Postuma, Nacer Hamdi,
   Nathan Heinrich, Vijay Kumar
CUA - Richard Trotta, Tanja Horn, Casey Morean
JLab - Dave Gaskell

Richard
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"Final" Heep Offsets
- The previous computed offsets were wrong due to the usage of an old BPM
  config file
- Using the corresponding BPM file, the offsets were updated
  - lowest 3 beam energies nearly unchanged
  - 8.2, 10.6 significant changes
    In units of 0.1%, 1mrad:
    dPe=-1.0, dPp=-2.0, dThe=1.0, dThp=1.1, dPhie=2.51, dPhip=-0.11
    dEe varying with beam energy
- pmx and pmy are improved, trade off between (W, pmz) and (pmx, pmy, E_miss).

Next steps same as last week.  Expecting to have Heep yield comparisons in 1-2
weeks.

Ali
---
- Helped Richard with the Heep offsets implementation
- Ongoing DeltaPi BSA study, planning to show some results next week

Vijay
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- had COVID all of the last week
- working on Luminosity study of summer 2019 data, hope to have initial results
  to show soon
- then will look at low energy Heep yield ratios

Alicia
------
- Now that Richard's offsets are finalized, batch script for 10.6 GeV Helicity
  replay is running

Discussion about discrepancy between pi+n MC and data MM distributions for
higher -t bins
1) treatment of radiative tail in SIMC
  - DaveG suggested to modify upper limit on Hard Photon radiative limit
    - this parameter changes how the distribution is calculated for determining
      whether a given event is within the spectrometer acceptance or not, to
      save CPU
    - if event-by-event calculations are done correctly, it should make no
      difference
    - indeed, adjusting this limit made no obvious difference

2) maybe the treatment of MM reconstruction resolution is incorrect in SIMC
  - this would imply an optics issue in the reconstruction
  - Dave: Did we check the missing mass resolution dependence with momentum
    transfer (-t)?
    - neutron MM peak clearly gets wider for higher -t bins in data, but not
      SIMC
    - Dave suggests that Alicia look at MM vs xptar, to see if there is a
      correlation in the data that needs to be corrected
    - Alicia: left side of neutron peak is described fine by SIMC, only the
      right side gets worse

3) Nacer: maybe it's an issue of missing background?
- Garth: we could try include non-resonant 2pi production background in SIMC
- Ali us using SIDIS as well as DeltaPi
  - SIDIS distribution already includes non-resonant 2pi
  - Alicia can add this from Portia's script last summer
  - Garth: the data show a rise at MM=1.08, the 2pi production threshold.
    Addition of these processes will not fill in the gap between the n peak and
    MM=1.08, so we will still need to deal with the n peak width issue at
    higher -t

4) maybe it's experimental background that needs to be removed?
  - Alicia showed plots both with and w/o HGC cut
  - Garth: HGC cut will create an inefficient zone in Focal Plane, but no leak
    through, as it's a greater-than cut
  - Alicia: since analyzing only region near n peak, was not planning to
    include a HGC cut in final analysis
    - GH: yes that's probably fine, but for a systematics check, we should
      calculate the asymmetry both with and without the HGC cut
  - Richard and Alicia will discuss PID cut systematics offline

Nacer
-----
Hodo Time Walk corrections
- redid 3.8 GeV, GH asked him to check a few runs in 2.9, 4.9 GeV, to be sure
  all is okay with the new calibs
- waiting for replays to finish

Nathan
------
- working on the the implementation of Junaid's new DC param files, to build on
  that for the next full replay
- fighting GIT on new parameter updates
  - learned a lot about GIT in the last few days
  - needed to make ~200 new param files
  - still have to modify standard.database to point to them, and test
  
- it sounds like it would be a good idea to make a new 2024 branch of PionLT
  and KaonLT after full replay completed

Junaid
------
- Pushed the latest updates for Drift chamber calibration.
- For the next step, discussed with Ali on the Report Files for the computation
  of the efficiencies
  - setting up report files for COIN data
  - updating cuts for efficiencies, compared to online values

Next Meeting
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- Thur Dec 14 @ 15:00 Eastern/14:00 Regina
  - PionLT will go first