Kaon_LT Experiment

                 May 15/25 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, Nathan Heinrich, Muhammad JUnaid, Ivan Zhenchuk,

   Nacer Hamdi, Ali Usman, Vijay Kumar, Alicia Postuma

CSULA - Konrad Aniol

Virginia - Richard Trotta

Ali

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piDelta MM shape study, refining high statistics settings

Q2=3.0, W=3.14 - now 3 t-bins, previously 2 t-bins

- new t-bins: 0-0.33, 0.33-0.42, 0.42-0.72

- low t center SHMS

  - pi+n (brown line) MC has more fluctutations in Delta region than other 2

    MC, might need to run it longer to get adequate statistics in tail

- mid t center SHMS

  - pi+n doesn't have very many events in this region, so removed it from fit

  - fit region is 1.11<MM<1.4 GeV

- mid t right SHMS

  - pi+n is included here

- mid t left SHMS

  - of 8 phi-bins, 2 are excluded due to difficult fits in Delta region

  - 4 phi bins are empty, so this leaves just 2 phi bins with fit data:

    -135 to -180, +130 to +180

- full phi coverage is obtained over 3 SHMS settings

- high t center SHMS

  - bkd much larger here than at lower t

  - there is data in all 8 phi bins, but 4 bins need to be excluded due to lack

    of Delta peak

- high t right SHMS

  - MM fits are done for only 2 phi bins, 0 to +45, -45 to 0

  - 2 phi bins excluded due to unclear Delta peak

  - 4 phi bins empty

- high t left SHMS

  - can do fits for all 4 phi bins with data

- full phi coverage is obtained, 4+2+4 phi bins in total over 3 SHMS settings

Q2=2.1, W=2.95

- new t-bins: 0-0.25, 0.25-0.33, 0.33-0.60

- only results for highest t-bin shown

- high t center SHMS

  - fit only 4 phi bins: 0 to +45, +45 to +90, -45 to 0, -90 to -45

- high t right SHMS

  - fit MM data for 2 phi bins: 0 to +45, -45 to 0

- high t left SHMS

  - fit MM data for 4 phi bins:

    +90 to +135, +135 to +180, -180 to -135, -135 to -90

- full phi coverage is obtained, 4+2+4 phi bins in total over 3 SHMS settings

Next steps:

- check that all shape study plots are ok

- then extract asymmetry and recalculate mean kinematics per t-bin

- start systematic studies on MM fit dependence

Nathan

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PionLT luminosity scans

- last week, noted some weird behavior in #counts surviving cuts.  Looked at

  actual numbers produced by scripts to diagnose

- found that scipy.integrate.* was used in scripts to integrate counts

  - this is not a true integration, rather a function is fit to the histogram

    and the fit is integrated.  Anomalies happen if the fit is not good

  - removed this function, now gets true #events in histogram

    - ***NB*** EXTREMELY IMPORTANT THAT EVERYONE CHECK THEIR SCRIPTS TO MAKE

      SURE scipy.integrate.* IS NOT USED ANYWHERE!!!

    - possibly this could explain some of the weird behavior Richard has noted

      in the past

- scaler yields are unchanged, but all histogram yields need to be rechecked

- Carbon Lumi

  - still need to recheck if Dave Mack's combinatoric ELLT is applied to

    scaler scans

  - Yield-NoTrack, Yield-Track generally look good, but some new outliers

    - investigating further

  - overall, very similar to earlier Lumi analysis, conclusions overall valid

- LH2 Lumi

  - some very large error bars for SHMS scalers but not HMS scalers, which

    doesn't look right, will investigate

- Coin Lumi

  - analysis still has a major bug, looking into it

- *NB* still looking at hodoscope time shift reported last week

Junaid

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PionLT LT-sep analysis

- calculating average kinematic variables for each t-bin

  - still need to calculate epsilon, theta* per bin

  - the angle variable is P.kin.secondary.th_pq

- also some discussion about units:

  - theta*,phi is in rad for data 

  - theta*,phi is in deg for SIMC (preferred)

  - phi in SIMC goes from -180 to +180, while in hcana it goes 0 to 2pi

- Richard did not make these consistent in recon_hcana, but did it in his

  analysis script

  - *NB* a good future task would be to add this in recon_hcana so SIMC and

    data have same units and ranges

- next step will be sig_UNS cross-section calculation from the Data/MC ratios

  and model

Richard

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KaonLT LT-sep analysis

- Q2=3.0, W=2.32

  - 5 iterations with same functional form as Q2=4.4

  - high epsilon, highest 2 t-bins:

    - some very low Data/MC ratios around phi=0, corresponding to right SHMS

      setting

  - overlay of Data and MC histos for kinematic quantities

    - MC has a double hump in W compared to data

  - lowest 2 t-bins have nice ratios

- Q2=4.4, W=2.74

  - Data/MC ratios overall look good

  - some shift between data and MC for Q2, W distributions

  - separated cross sections

    - sigL<sigT in general, but 3rd t-bin has sigL high compared to the others

- planned systematic studies

  - presents a summary of systmatic error types from KaonLT proposal

Vijay

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Low Q2 pion absorption correction study

- removed PID cuts from Alicia's script since he is using CoinTime and RF cuts

  instead of Cherenkov

- getting a smaller correction factor than Alicia at low pion momentum

- next step will be to finalize Q2=0.425 yields

Nacer

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Low Q2 KaonLT LT-sep analysis

- working on average kinematic variables per t-bin

  - averages are calculated after pion-leakthrough and Dummy subtractions

  - had to replay data because theta* was missing from ROOT trees

- formed R=Data/MC ratios for each t-phi bin

  - then form weighted average R per t-phi bin

  - when combining ratios, if counts=0 set error=100 so it doesn't contribute

    to weighted average

- found an error in boiling factor when computing yields

- also needs to correctly propagate the uncertainty in the beam current/charge

  - for KaonLT BCM calibrations, see Dave Mack's report:

    https://hallcweb.jlab.org/doc-public/ShowDocument?docid=1034

- Lambda: low epsilon, R about 2

  - high epsilon, some random bins are zero, overall R about 2

  - *NB* Richard: suggests to make MM plots for each t-phi bin to better see

    what's going on, maybe the pion subtraction needs adjustment?

- Sigma: R about 8

Alicia

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u-channel analysis

- incorporating Pythia generator for high MM background into SIMC

  - got output files from Pythia into SIMC

  - Sylvester Joosten had added a lot of containerization to SIMC for ANL

    cluster that Alicia removed

  - still getting some code crashes

- hoping to have some plots by next week

Next Meeting

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- Thur May 23 @ 15:30 Eastern/13:30 Regina

  - KaonLT will go first

  ** THIS TIME WILL BE USED AT LEAST UNTIL THE END OF AUGUST **