Kaon_LT Experiment

                 Mar 21/24 PionLT/KaonLT Analysis Meeting Notes

                 ----------------------------------------------

                                (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

-------

Regina - Garth Huber, Nacer Hamdi, Ali Usman, Alicia Postuma, Muhammad Junaid,

   Nathan Heinrich, Vijay Kumar

JLab - Dave Gaskell

FIU - Pete Markowitz

CSULA - Konrad Aniol

CUA - Casey Morean, Tanja Horn

Nathan

------

PionLT luminosity scan analysis

- worked on getting Richard's Lumi script working

  - shows initial result of first lumi scan in 2021 (Carbon runs 12144-12151)

  - these runs have a BCM calib from Dave Mack

  - only 4 of 9 points shown, some plotting bug to fix

  - SHMS Rate up to 200 kHz, current up to 70uA

  - the 4 points so far look reasonable, but more work to be done

- Dave: what is "Relative Yield Scaler"?

  - probably is ELREAL scaler, but need to check

- will work on single arm Lumi scan after the script is better understood

  - that scan will require a BCM calibration, will check with Dave Mack

Junaid

------

PionLT Heep analysis

- no plots to show this week

- ran SIMC for all HeepCOIN settings, will do fits for GH offset studies

Garth

-----

Modifications to SIMC for pion scattering in SHMS collimator

- located Fpi-2 HMS collimator routine for implementing in SIMC

- Dave: SHMS collimator is 2.5 inches thick

- Stephen: docDB report on SHMS collimator:

  https://hallcweb.jlab.org/doc-private/ShowDocument?docid=1104

Ali

---

piDelta BSA

- starting on 3 highest Q2, where no HMS delta-correction is needed

- MM shape study

  - SIDIS and RHO dists so similar, so will just use SIDIS

  - shows example fit using either just SIDIS or just RHO

    - SIDIS fits are a bit better than RHO

  - plots of fitting still in progress

  - running SIDIS MC for more statistics

- Q2=3.0, W=3.14 t-binning

  - this setting has enough statistics for 2 t-bins

  - can't use just SHMS center setting to determine binning, need to use L,R,C

    to get stats over full t-distribution

  - places a tight cut on piDelta MM region to get approximate statistics for

    binning without doing a background subtraction

  - will divide the t-dist at -t=0.425 for the 2 tins

- Ideas on Systmatic Error estimate for Delta fitting

  - Option 1: compare BSA using integration of Delta MC fit to data, to BSA

    determined from (Data-SIDIS-pi+n fits)

  - Option 2: compare BSA when varying the pi+n and SIDIS fits

    - fit pi+ at peak, or at just the tail (an extreme case)

  - Tanja: exactly what systematic are you trying to determine here?

    - GH: expecting the uncertainty from the Delta fitting to dominate over the

      MM cut dependence, since the Delta peak is not clean (unlike pi+n) it is

      not so obvious that we can disentangle the Delta fitting systematic from

      the MM integration region systematic

  - Dave: when fitting pi+n MC, do you fit to the height of the peak, or the

    integral within some MM region to be less sensitive?

    - Ali: fits just to the pi+n peak

    - Dave: try to fit integral within some FWHM (or other region) and get the

      integrals to agree instead

  - Tanja: trying a variety of different methods to understand how various

    effects may be correlated seems the best approach

Alicia

------

HMS delta-correction in hcana

- hcana compilation issues

  - eventually got it to work after info from Stephen, Ole

- editing SpectrometerClass

  - found that Tanja's old Q3 correction (fSatCorr) is already implemented in

    code

  - kept that architecture, but added two new options for P_HMS=5.3, 6.5

- MM vs hsxpfp plots shown for:

  - P=6.59, Run 4873

    - if hsxpfp>0, hsdelta+=3.0 hsxpfp  -- LOOKS GOOD

  - P=5.29

    - if hsxpfp<0, hsdelta-=5.0 hsxpfp  -- OVERCORRECTS, 4.0 looks better

- running batch jobs for replaying these data

  - have "nearly final" BSA values for other three Q2 settings

Dedicated meeting to discuss BSA errors, for April 1 or 2

- please fill out poll at:

  https://www.when2meet.com/?24252350-iFG7B

Vijay

-----

Low Q2 PionLT analysis

- no plots to show this week

- working on Data/MC ratio plots with only Central SHMS setting

  - encountered unexpected errors, still debugging

  - last week's plots with all SHMS settings are available on RedMine

- in addition, trying to understand MC iteration process

Nacer

-----

Low Q2 KaonLT PID studies

- no plots to show this week

- trying to get a good RF cut, other PID cuts are mostly ready

  - will try to reduce pi+n peak w/o cutting into Lambda/Sigma events

  - GH: once you decide on an RF cut, you will want to go back and recheck the

    other PID cuts as it will be a bit easier to distinguish small K+ from big

    pi+ sample

  - Nacer: if RF cut works really well, maybe won't need HGC cut, which would

    simplify other parts of analysis

Stephen

-------

SHMS NIM paper

- thanks to everyone for submitting plots for NIM paper

- has all of the needed plots now, will try to implement them soon

- will aim to have paper ready for submission to NIM by end of April

N*2024 Conference at York, June 14-21

- asked to give a 20 minute talk on meson form factors

  - will ask for update plots for the presentation

- will distribute an abstract soon

Next Meeting

------------

- Thur Mar 28 @ 15:00 Eastern/13:00 Regina

  - KaonLT will go first