Apr 25/24 PionLT/KaonLT Analysis Meeting Notes
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                                (Notes by GH)

                     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 - Garth Huber, Nacer Hamdi, Ali Usman, Alicia Postuma, Muhammad Junaid,
   Nathan Heinrich, Vijay Kumar
York - Stephen Kay
JLab - Dave Gaskell
CSULA - Konrad Aniol
CUA - Tanja Horn

Vijay Kumar
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Initial results of Low Q2 PionLT L/T-separations
- changed formula for sigT to a+b*(-t) type form for now
- fits now converge, was able to do several iterations

- comparisons between Data and MC distributions look reasonably good
  - should change lower MM cut to ~0.91, or remove entirely, to avoid
    correction for events lost due to the cut

- Exp/MC ratios are approximately 1, but with some phi-dependence for some
  t-bins
  - GH and Vijay will need to look more closely at these, with the aim of
    making the ratios more flat vs phi
    - likely will have to modify the sigT equation to get a better fit, need a
      close look to see what to do
    - possibly the LT, TT equations will also need modification

- sig_UNS phi distributions looking better than before, the phi distribution is
  getting more consistent between low, mid, high-epsilon
  - these will hopefully improve further once the ratios are more flat vs phi

- initial L/T/LT/TT cross sections
  - sigLT has a trend to values closer to zero as -t decreases, but the
    smallest -t bin does not have the smallest magnitude, this will need
    investigating
  - the t-dependence of sigL also will need confirmation, likely it will change
    as the iterations continue

- showing results at weekly meetings  in order to gain feedback is important,
  we are willing to have Vijay go first for the next few meetings, if this is
  helpful to him

Ali
---
- recon_hcana was using wrong mass, gave weird phi-distributions
  - this has now been fixed
  - unfortunately, all SIMC needed to be re-run, as old files were deleted

Alicia
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BSA systematic uncertainties
- A=full fit, A'=simple fit, typically A<A'
- quoting A as final value, with syst_fit=|A-A'|
- showing this as a +/-systematic over-estimates the uncertainty, as the real
  value presumably is between A and A'
- agreed that we will show syst_fit as an asymmetric error

- will not be present next week due to other obligation, hoping to give an
  update on the BSA paper in 2 weeks

Nacer
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KaonLT Low Q2 PID efficiency systematics checks
- recap of Ali's 2023 slides where HMS_cal and HMS_cer efficiencies were found
  using Heep runs
  - runs 6600, 6603 were from this data set
  - used only 2-4 GeV/c runs to avoid pi- Cherenkov radiation
  - for CAL_eff, placed tigher cuts on CER, and vice versa
  - small rate dep was seen in CER_eff, Ali took the average, and found a
    systematic from the RMS deviation

Nathan
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PionLT BCM calib
- met w/Dave Mack this morning to discuss Nathan's initial results
  - DM thinks a combined fit using runs w/same config can eventually be used
  - suggested that Nathan look at BCM1,2 and throw away runs>50uA due to
    small non-linearity
  - will check how stable the parames are before doing a combined fit
- DaveM's main concern from Nathan's Lumi work so far is that the found 170nA
  offset is too large, was expecting an offset closer to 70nA based on prior
  experience
  - will recheck the offset after calibs complete
- Nathan will write a README on the changes to the calib code after complete

Junaid
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- finding his experience @ JLab to be very valuable

Next Meeting
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- Thur May 2 @ 15:00 Eastern/13:00 Regina
  - PionLT will go first