Kaon_LT Experiment

                 Oct 3/24 PionLT/KaonLT Analysis Meeting Notes

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                                (Notes by GH)

                     Today: PionLT 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, Muhammad Junaid, Nathan Heinrich, Vijay Kumar,

   Nacer Hamdi, Alicia Postuma

FIU - Pete Markowitz

Ohio - Julie Roche

Virginia - Richard Trotta

CUA - Tanja Horn

JLab - Dave Gaskell

Nathan

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PionLT COIN Luminosity studies

- made a mistake in setting up scripts, had e+ tracking eff instead of proton

  in SHMS

- replaying files again, hopefully will have some results for next week

Junaid

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PionLT PID studies

- completed HMS e- selection

- now doing SHMS pi+ selection

  - using 9.177 GeV data

  - using RF time, Aerogel, HGC to select clean sample

  - will look at 3 physics settings, one where SHMS is at 5.5deg to check for

    backgrounds

- planning to have a report next week

Richard

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KaonLT LT-separations

- looked at W-dependence, comparing Q2=3.0, W=3.14 with Q2=3.0, W=2.32

- adjusted exponent in Wfac=1/(W^2-mp^2)^n from n=2.0 to n=2.25 and n=3.40

  - Tanja's global K+ analysis had n=2.25

- seems to put ratios near 1 instead of 0.3-0.5

  - Dave: confused about this.  Changing the exponent should only afffect the

    Data/MC ratio for 1st iteration, but ratios would get rescaled in further

    iterations

  - Richard: the ratio seems to persist near 1 for first few iterations, will

    try more

- will look at both Q2=3.0 settings for comparable t-ranges and see what is

  best value of exponent

  - would try different n manually, not as a free parameter in the fit

  - then would look at other Q2 settings, to see if a global n value works or

    not

Vijay

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Low Q2 PionLT systematic uncertainties

- earlier studies showed HMS delta was very sensitive to +/-10% change in cut

  value (as in Tanja's thesis)

  - Dave: should not go past +/-8% HMS delta range, as Matrix Elements are not

    as well constrained.  In general, for both spectrometers keep within the

    nominal cuts and only make them tighter, not looser

- found that only the low epsilon data covers +/-8% delta range, mid and high

  epsilon data do not fill whole focal plane, due to the applied diamond cut

  (obvious in retrospect) and are not affected by the +/-10% cut variations

  - doing an LT-separation with this cut will not make sense, as the cut

    variation effectively makes the diamond smaller for low epsilon data, but

    not the mid or high epsilon data

- will compute sig_UNS instead, for only low epsilon data

  - this will be more comparable to the study shown in Marco's thesis

Data replay and preservation

- planning to replay Q2=0.42 data next week

- unfortunately, the Q2=0.38 data were not backed up, will replay it as well

- Tanja: it is important to also archive the code used to generate the data, so

  they're linked together

- Tanja: it is also important to do some tests to make sure the new Q2=0.38

  replay is not different than the old one

Alicia

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BSA manuscript changes

- please review the draft manuscript on OverLeaf

- went through draft response to editor and Referee B

  - incorporating GH's comments then will circulate to group via PDF

- would like to resubmit to PRL by Oct 11

Nacer

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KaonLT Heep singles

- finished replays

  - need to set up config files for report files

- Junaid sent SIMC configuration files for singles

Next Meeting

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- Thur Oct 10 @ 16:30 Eastern/14:30 Regina

  - KaonLT will go first