Kaon_LT Experiment

                 Dec 14/23 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, Ali Usman,

   Vijay Kumar, Alicia Postuma, Nacer Hamdi

CUA - Richard Trotta, Tanja Horn

JLab - Dave Gaskell

FIU - Pete Markowitz

Nathan

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Getting ready for full replay of PionLT data

- param files in standard.database are set up

  - modifications to param files done by some scripts, took several days to get

    everything working

- CoinTime offset needs adjustment due to RefTime cut change

  - wrote a sript to plot CoinTIme, want it centered around 0 w/ new offset

  - replays to determine new CT offset worked

    ~30 runs done so far, more planned

  - PTRIG6 runs will require different CT offsets than PTRIG5 runs

- full replay going soon

Junaid

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More on getting ready for full replay of PionLT data

- updated def cuts for efficiency studies, report files

- setting up batch scripts before starting full replay

Richard

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Batch job information

- recommends to separate hcana replay from python script job

  - makes memory allocation for jobs easier

  - need to increase memory efficiency for batch jobs in order to get a good

    running priority

  - 800MB seems to be a good allocation for hcana replays

  - python request needs 10GB, seems large, needed for jobs to run properly

  - GH: try creating a python binary for production running, interpreted python

    is good for development, but is inefficient for large scale running, this

    should reduce memory usage and CPU time

- newest replays at:

  /lustre19/expphy/cache/hallc/kaonlt/Pass3_Dec_2023

- rough vresion of script that calculates resource usage:

  /u/group/c-kaonlt/USER/trottr/lt-analysis/usage_check.sh

- meeting w/ Ali to discuss efficiecies, uncertainties in effs, Heep yields

- Ali mentions that we also need to implement offsets into SIMC physics input

  files

Ali

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pi+ Delta0 BSA analysis

- starting w/ Q2=2.115, 3.0-2.32, 3.0-3.14 settings

- MM study in Delta region

  - need bin-by-bin shape study

  - SIDIS scaled to data in MM=1.4-1.55 GeV region

  - pi+n MC scaled to neutron peak

  - Delta MC is matched to data after n, SIDIS are subtracted

  - Delta yields calculated for MM=1.1-1.4 GeV region for each helicity setting

  - BSA calc separately for Delta, Bkd, Sum Yields

- maybe we can do 2 t-bins for 2 FF points (higher statistics) after adding

  Left, Center, Right SHMS settings

Things to be done:

- check rho contribution to this MM region

- implement kinematic offsets in analysis

- understand pi+n resolution difference

Dave: it's important to confirm you're doing a Dummy target subtraction

- surprised the piDelta BSA is so close to the BSA asymmetry, is there a good

  physics reason why they're so similar?

- it would be helpful to calculate also the BSA for the 1.35<MM<1.55 region, to

  see if the BSA is different there or not

Discussion on the pi+n resolution difference:

GH: the HMS drift chamber resolution in SIMC is set in:

  hms/mc_hms_hut.f

  variable: hdc_sigma is set to 0.030 for each plane

  - similarly for SHMS in shms/mc_shms_hut.f

  DG: first need to look at correlations between FP variables and MM before

  making adjustments

  - Alicia had done an intial look at this, but wasn't completed.  Will look in

    more detail after the holidays

Dave: also need to confirm whether NGC is in shms_hut.f or NOT

- want it OUT for KaonLT, IN for PionLT

- it would be great if Dave could add an input flag which would set this,

  otherwise, we will need different versions of the code for KaonLT, PionLT

Dave: Maybe the beam energy spread is the issue?  PROBABLY!

- in 6 GeV era, the beam energy spread was never an issue

- but it's significantly worse for 10 GeV beam!

- Note that this refers to the width of the beam energy distribution, and is a

  different parameter than the uncertainty in the beam energy (which refers to

  the uncertainty in the centroid in the distribution), not the width

  - For an accurate simulation, SIMC does not use a monochromatic beam energy,

    but rather has a Gaussian energy distribution given by this width

- DG finds a 2013 Note: at 11 GeV the spread is 0.02%, at 6 GeV 0.01%.  No

  mention of what it is at 8.5 GeV

  - GH will write Jay Benesch to get more info

Alicia

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Reprocessing 10.6GeV data with offsets

- will look at memory issue mentioned by Richard for batch jobs

- next step will be MM study, binned in t

Nacer

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Calibration checks of 3.835, 4.933 GeV KaonLT data

- SHMS beta distribution was around 1.1, with new Hodo time walk parameter

  (determined from 3.8 data) beta is now closer to 1

  - good news, this time walk param also works well on 4.9 data

- next step is to check if this makes any effect on DC calib

- Ali: new offsets should be automatically implemented in his analysis, if he's

  pointing to the right files

  - NH should confirm with AU this is the case

Vijay

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Lumi and Heep cross section check for Summer 2019 data

- using Richard's method for Lumi

- results: Carbon -0.243%/100uA   LH2 -5.06%/100uA

  - consistent with Richard's results, which is good

- Heep MC/Data yields are also consistent with 1, within errors

Dave: the plots look a bit weird in that the error bars for many points are

  quite large (+/-5%)

  - Pete: judging from the small scatter of the data, it looks like the error

    bars are over-estimated

  - Ali: we had originally over-estimated the tracking efficiency

    uncertainties, maybe that's an issue?

  - Garth: or maybe it's simply an error in the plotting script?

  - either way, this needs to be rechecked, as the uncertainties on the Lumi

    and Heep checks are very important!

- another issue to check: it's very important to confirm that an error-weighted

  fit of the results is done

- the results are very encouraging, but some checks are still needed

Next Meeting

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- Thur Dec 21 @ 15:00 Eastern/14:00 Regina

  - KaonLT will go first

- there will be no meeting on Dec 28

- our first meeting of 2024 will be on Thur Jan 4

- after that, we will have to see what people's schedules are for the new

  semester and see if this time still works for everyone, or not