Kaon_LT Experiment

                 Mar 27/25 PionLT/KaonLT Analysis Meeting Notes

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

                                (Notes by GH)

                     Today: KaonLT will be discussed first

Present

-------

Regina - Garth Huber, Ali Usman, Alicia Postuma, Nathan Heinrich, Vijay Kumar,

   Nacer Hamdi, Muhmmad Junaid

CUA - Tanja Horn

JLab - Dave Gaskell

FIU - Pete Markowitz

Ohio - Julie Roche

Virginia - Richard Trotta

Alicia

------

Update on Geant4 proton absorption simulation

- last week, we reviewed a substantial change in missed tracks vs momentum,

  investigating this more deeply to understand what's going on

- interesting observation: many tracks stopping in the simulation produce

  energetic secondaries that produce tracks and apparently satisfy the trigger

  conditions

  - total interactions are indeed nearly momentum independent, as expected, but

    this is not the right criterion as an interaction does not necessarily

    equate to a lost event

   - total interacting tracks is very similar to spreadsheet prediction

- for incident protons, the largest fraction of secondaries is protons,

  followed by neutrons, then gammas, pi+

  - at 10 GeV/c, ~90% of reactions produce energetic secondaries

  - whether you count the secondary depends on where it is produced, its

    energy, etc.

- correct for:

  Missed Events= Missed 3/4-Trig + 3/4-Trig with wrong PID

  - added to simulation the predicted signals from PID detectors for the

    secondary particles

  - user would evaluate a correction for their analysis based on cuts applied

- Garth: while this is fresh in Alicia's mind, it would be good to compute

  proton corrections for all of her physics settings.  After that, maybe can do

  a tutorial to show everyone else what to do

  - Alicia also plans on writing up a tech report with instructions

- Well done Alicia, this looks like a really useful tool!

Junaid

------

Setting up for PionLT Q2=3.85, W=2.62 LT-separation

- using Aerogel and RF for pi+ PID

- compared MM between data and SIMC

  - fit peaks to determine MM shift to data

  - low epsilon settings require negative offsets

  - high epsilon settings require positive offsets

  - in both cases, the shifts are about 5 MeV

- decided on a MM region cut of 0.90<MM<1.06

  - agreement between MC and data for MM tail looks good to slightly past 1.06

  - Ali's SIMC resolution correction is applied

  - also SHMS collimator rescattering flag is enabled

- diamond cut: tested on both data and MC for all settings, looks good

- working on t-resolution test and t-phi plot to decide t-binning

Vijay

-----

Setting up for PionLT Q2=0.425 LT-separation

- looking at t-phi plot at high epsilon to select t-region with complete phi

  coverage

  - needs to add t-circles to plot to better judge the coverage, but things

    generally looking good

- kinematic offsets have been applied to SIMC input files

- need to make small adjustments to diamond cut, based on comparo with MC shown

  last week

- should have expt yields per t-phi bin soon

Richard

-------

Had iFarm missues this week, so not much progress

- rerunning SIMC for Q2=5.5 and Q2=3.0, W=2.32 settings

Nacer

-----

Setting up for KaonLT Q2=0.50 LT-separation

- checking phi coverage with t-phi plots at high epsilon

- Lambda:

  - good phi coverage for -t=0.07-0.15

  - highest t-bin was 0.13-0.166.  Will adjust this down to 0.13-0.155

- Sigma:

  - t-bin range was 0.095-0.205, will narrow this to region of good phi

    coverage, -t=0.107-0.18

Ali

---

pi+Delta0 BSA

- thesis should be sent to External Examiner next week

- then will start systematic studies and finer t-binning check

Nathan

------

PionLT coin Lumi studies

- new set of Lumi plots with CPULT+DMack ELLT corr

  - vs Coin Rate: lots of scatter

  - vs SHMS Rate

  - vs Beam Current

    - some individual settings vs current have a curved correlation instead of linear

  - vs (SHMS-3/4+HMS-3/4) Rate

  - vs HMS Rate

  - all show large decreases but with lots of scatter

  - it's clear there is something else going on, but hard to tell what from

    these plots alone

- CoinTime plot indicating Coin Blocking that Dave shared from SIDIS run is not

  yet studied

  - Tanja: maybe an old 6 GeV thesis gives some useful info on how to proceed?

    Try looking at:

    J. Volmer, p. 72-73  Sec 5.4.3: Coincidence blocking and timing correction

    T. Horn, p. 138-140  Sec 3.6: Coincidence blocking

  - Nathan will also check with Dave for advice, as 12 GeV DAQ may require a

    different methodology than 6 GeV correction

  - the hope is that this correction will reduce the scatter and make it more

    clear what (if any) additional empirical correction needs to be applied

    - we also would like to have some reasonable explanation of the origin of

     the inefficiency needing correction

Next Meeting

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

- Thur Apr 3 @ 16:30 Eastern/14:30 Regina

  - PionLT will go first

- NOTE: meetings start 16:30 Eastern/14:30 Regina from March 13-April 10

  - after that, we can return to 15:30 Eastern for the convenience of our USA

    colleagues