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Kaon LT Meetings » mtg_24apr04.txt

Garth Huber, 04/04/2024 04:56 PM

 
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                 Apr 4/24 PionLT/KaonLT Analysis Meeting Notes
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                 ---------------------------------------------
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                                (Notes by GH)
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                     Today: PionLT will be discussed first
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Please remember to post your slides at:
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https://redmine.jlab.org/projects/kltexp/wiki/Kaon_LT_Meetings
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Present
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-------
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Regina - Garth Huber, Nathan Heinrich, Nacer Hamdi, Ali Usman, Alicia Postuma,
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   Muhammad Junaid, Vijay Kumar
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FIU - Pete Markowitz
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Nathan
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------
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PionLT Lumi update
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- still waiting on Dave Mack re BCM calib, will prompt him tomorrow
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- have calibs that are valid for 2 lumi scans @ 9.2 GeV, show first results
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9.2 GeV Carbon Scan #1
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- sees a small trend in HMS TrkEff over 0-15 kHz range, 99.8-99.75%
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- SHMS TrkEff shows similar trend, but up to 200 kHz
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- sees a 5% drop in RelYield at low beam current, corresponding to a 5%
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  over-estimate of beam current at 3uA, a 0.15uA offset
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9.2 GeV Scan #2
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- similar trends seen
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Some questions about corrections to the beam current in the scripts
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- first there is an unusual logarithmic correction to the beam current
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  attributed to Peter Bosted
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- after this, a second correction is applied
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- both are applied to the values used in Nathan's analysis
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- more investigation is needed to understand these
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- would like to discuss them with Richard
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- it would be helpful also if Vijay could check what's in his code
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Junaid
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------
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PionLT Heep Coin settings
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- list of cuts shown for both data and SIMC
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- data are normalized for Q and TrkEff
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  - DetEff and EDTM are not yet applied
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  - BCM calibs not yet correct
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- Data MC comparos shown for a variety of variables for all 9 Heep settings
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  - overall the shapes agree nicely
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  - rebinned plots for Heep offsets
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  - PMY will be used to determine OOP offsets
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  - Ali: notices that PMZ, EM resolution is much worse than predicted by SIMC
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    - could be due to a BPM calib error
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    - will discuss this further with Junaid
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Ali
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---
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piDelta BSA study
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- results shown for Q2=3.0, W=3.14 high statistics setting
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  - 2 t-bins, 8 phi-bins
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  - bins with very low statistics or Delta fit fails are excluded
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- Procedure used for MM fit:
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  1) fit pi+n MC by matching integrals over 0.92-0.96
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  - MC is narrower than data, so matching integrals results in the peak being
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    too high, which is offset by being below data in the width
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  2) fit SIDIS MC in region with minimal Delta contrib, 1.4-1.5
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  - for bins where the data don't extend all the way to 1.5, the fit region is
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    slid slightly lower, keeping the fit region width the same
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  3) then fit piDelta MC to Bkd subtracted data
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  4) sum of MC is formed after all fitting
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- Result of fit shown for low -t, all phi bins, L,C,R SHMS
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  - this is first time fits are shown with longer SIMC data runs
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  - resulting MC distributions are smoother, resulting in better fit overall
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  - MC consistently under-predicts 1.0-1.06 MM region
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    - possibly the SHMS collimator scattering that GH is implementing will help
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      fill in this region
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  - there is a slight over-prediction of data around 1.1 in -90 to -45 phi bin,
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    can be included in systematic
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  - Right SHMS: 4 phi bins
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    Left SHMS: only 2 phi bins, 2 bins removed due to failed fits, will show GH
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    later
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  - BSA shown vs phi, weighted average of L,R,C
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    - BSA calculated by integrating Delta MM from 1.12-1.4 GeV
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      - will do a MM cut dependence study later
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    - resulting asymmetry is very nicely sinusoidal
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Vijay
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-----
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Low Q2 pi+ LTsep iterations
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- getting some weird results fitting interference terms
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  - new params from fitting process not behaving as expected
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  - going through code again to see if there is a bug
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  - if checks don't find anything, will try setting LT,TT to zero and try
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    improving from there
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Alicia
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------
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pi+n BSA error analysis Part 2
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- first show of Q2=3, W=2.32 results
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  - BSA are similar to before delta-correction
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  - t=0.25-0.30 still has a wonky phi distribution
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- Q2=2.1, W=2.95
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  - first bin (-t=0.01-0.04) full fit is over-fitting, but still gives results
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    consistent with other bins
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- Some small changes to Systematics Calc from Tuesday's discussion
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  - will not include (A-A') simple vs full fit comparison in RMS of
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    cut-dependence study
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  - (A-A') is much larger than the others, so lumping it into RMS calculation
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    would result in under-estimate of uncertainties
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  - delta(CUTS)=RMS[ (A-CN), (A-CW), (A-MN), (A-MW) ]
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  - shows table of errors for each point at one Q2, STAT, CUTS, BPOL, FIT
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  - then takes SYST as sum of CUTS, BPOL, FIT in quadrature
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  - shows LT' results vs -t for each setting, with double error bars
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  - we should be able to finalize the selection of CLAS data to compare to ours
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    for Q2-scan at fixed X_B soon
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Nacer
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-----
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Low Q2 KaonLT RFtime correction
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- plot of P.gtr.th vs RFtime shows correlation, data is for 4-5 runs
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- fits a straight line: 0.64-3.05*xptar
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- applies this as an adhoc correction, RFcorrected
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- plot of MM vs RFcorrected shows even better separation between K+L, K+S and
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  piDelta than before
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  - width of piDelta band is narrower than before
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  - will redo cut study using RFcorrected
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  - can clearly see some K+L events wrapped around the bottom of plot
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    - could not see these before due to wider pion background
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    - will need to place a lower limit on pion cut at ~0.1 to keep them
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    - alternately, can adjust RF offset by ~0.5ns to better center the K+L
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      events in the RF window
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Next Meeting
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- Thur April 11 @ 15:00 Eastern/13:00 Regina
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  - KaonLT will go first
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