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Kaon LT Meetings » mtg_23oct03.txt

Garth Huber, 10/03/2023 07:22 PM

 
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                 Octt 3/23 PionLT/KaonLT Analysis Meeting Notes
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                 ----------------------------------------------
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                            (Notes by GH, AH & RT)
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                     Today: KaonLT 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 - Alicia Postuma, Muhammad Junaid, Nacer Hamdi, Nathan Heinrich,
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   Vijay Kumar, Garth Huber
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CUA - Richard Trotta
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FIU - Pete Markowitz
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Richard
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-------
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Q2=2.1 R=Data/SIMC plots vs phi for t-bins at low, high epsilon
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- Sync the range of angles between SIMC [0, 2Pi] and hcana [-Pi, Pi]
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  - added pi to hcana phi
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- high ratios at phi=240,280 deg consistently for all 3 t-bins, SIMC events go
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  to zero for these bins
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  - unweighted distributions show events in these bins, so it is presumably a
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    weighting issue
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  - sigTT is calculated way too large for some bins as well
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- using starting parameters from LD+ Fpi-2 analysis
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  - no changes to t-average calculation yet
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  - m_pi pole factor not yet modified for m_K
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  - no (Q2,W) scaling appiled yet to leading parameters
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    - this may solve the issue, the important thing is to estimate a set of
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      initial starting parameters that behave reasonably, Richard will need to
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      do a by-hand calculation to find them
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Some high epsilon data have two slightly different TH_shms, e.g. some right
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setting data were taken initially and came back to take more statistics later,
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the TH_shms differ slightly between the two sets
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- Garth: for the experimental data, need to select the right angle for each run
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  number in standard.kinematics
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  - for SIMC, if the difference is small (typically 0.005deg), run SIMC using
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    the mean angle of the data (weighted by the accumulated beam charge)
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Still running Heep for offset check
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- getting ifarm replay errors: SLURM FAIL
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- Nathan also has ifarm issues since Friday
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- will follow up with IT tomorrow
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Vijay
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-----
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Sent Heep plots for new offsets to GH yesterday
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- looking at comparison of tar and spectrometer variables between data and SIMC
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  after reconstruction script
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Lumi studies will start son
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- low current BCM calibs are very important to the low Q2 data!
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Nathan
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------
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Hodscope calibration ongoing (V_prop 2021 data)
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- met w/Junaid to explain the calibration process
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- batch errors lead to slowing calibration jobs
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Junaid
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------
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Helping Nathan with Hosdoscope calibration (V_prop 2022 data)
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- was using Stephen's old scripts, now switched to new scripts
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- one of the points of NH and MJ work is that we don't know how many different
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  sets of V_prop will be needed, so need to calibrate a selection of all data
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  to study parameter stability
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  - V_prop is a whole matrix, so many more parameters than time offsets
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- using interactive so far for script testing, so not yet delayed by ifarm
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  issues
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Alicia
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------
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HGC vs. Aerogel Cherenkov NPE (10.6 GeV data)
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- Noticed negative NPE in the HGC! 
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  - 2D plot of HGC vs Aero
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    - events w/ HGC npe<0 but Aero having 5-20 npe
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  - needs some investigation of the HGC calibration for these runs
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- Vijay quickly confirms that HGC calibrations for 10.6 GeV data were done for
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  runs 4875-5325
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  - first step is for Alicia to confirm that she is using the correct
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    calibration files
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Nacer
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-----
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- going through event selection & variables for low Q2 KaonLT data
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---------------------------------------------------------------------
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Post-Meeting on CoinTime leakage in 10.6GeV KaonLT data
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- Dave, Richard, Alicia, Junaid, Nacer, Vijay, GH
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Alicia shows plot of CT (range -30,30+log z) vs MM (pi+n PID)
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- mmpi_10p6.pdf
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- see a band with good pi+ MM over a wide range of CT
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- the behavior is atypical, but could be due to poor CT timing resolution
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  during 10.6GeV run, which was fortunately fixed before rest of KaonLT run
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- Nacer confirmed at Regina group meeting that this behavior is absent in 3.8
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  GeV data, no CT band at pi+n mass
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- Dave: Why is the band not through whole region?
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   - Should be at other MM peaks (ie K+lambda)
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   - Is it just because pi+n is so large, and harder to see in lambda?
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     - this is most likely the case, Alicia changes some cuts to select
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       pi+Delta region and the problem seems to be there too, although more
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       washed out in MM
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- Dave: can have singles within cointime window and steal the good time
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  (making it show up at bad time) although the tracking algorithm still picks
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  up the correct MM
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  - In general, this should have a very small probability, unless timing
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    window cuts are wide open
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    - need to treat CoinTime like any other detector and place time windows on
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      both legs into CoinTime module
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Richard confirms that Timing windows for KaonLT hallc_replay are set:
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github.com/JeffersonLab/hallc_replay_lt/blob/LTSep_Analysis_2022/PARAM/
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  TRIG/KaonLT/PARAM/tcoin.param
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- *Alicia* will double check that this is set the same way in hallc_helicity
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  analysis
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*Richard* needs to add CT vs MM for lambda analysis (log scale CT, no CT cuts)
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to confirm whether he sees the same behavior
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- we have to deal with the issue either way, but how we approach it would be
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  different, whether or not he sees it
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Dave: Maybe non-Gaussian behavior caused by the reversed signal to CoinTime
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module causes it to broaden in the CT spectrum so we're seeing long
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non-Gaussian tails
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- Dave suggests: Check Heep 10p6, since no randoms shouldn't be seen for clean
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  elastics.  This would allow us to estimate the size of non-Gaussian tails
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This suggests two possible ways to correct for the issue:
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- Dave's way: use Heep CoinTime distribution to estimate size of Non-Gaussian
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  CT tails
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- Garth's way: subtract "far randoms" from "close randoms" in physics data to
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  get size of Non-Gaussian tails
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- best to check both methods.  If consistent within errors, then can apply
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  easier-to-determine Heep correction to 10.6GeV KaonLT physics data
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Richard finds a Heep-COIN 10p6 replay that we can look at
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- CT looks very asymmetric even here, non-Gaussian tails -25 -> -5 and +5 ->
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  +20 ns (plot posted on RedMine)
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  - heep_coin_time_10p6.pdf
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  - Cuts applied:
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    tv__tree->Draw("CTime_epCoinTime_ROC1","abs(CTime_epCoinTime_ROC1)<50 &&
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    abs(hsdelta)<8 && H_cer_npeSum>2 && ssdelta>-10 && ssdelta<20 &&
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    P_aero_npeSum<2","", 86385, 0);
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Dave: Beta cut may be hiding the issue, a comparison may be useful
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- Plot of P_gtr_beta vs CoinTime for Heep-COIN replay
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  - ctime_vs_beta.pdf
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- beta has a bifurcation that occurs outside usual cut abs(beta)<0.3
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  - Richard and Stephen saw this effect with beta much earlier, but didn't
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    investigate further
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- Alicia coinfirms that 10.6GeV physics data have the same issue
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  - cointime_beta_10p6.pdf
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  - *Alicia* will explore CT vs beta to see if cutting it makes much difference
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  - seems likely that we should remove beta cut as it complicates the
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    correction for non-Gaussian tails, particularly since beta provides limited
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    PID information at high momentum
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  - Alicia and Richard will ask Stephen about this, but this CT asymmetric
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    peak generally might be a good thing to bring up for the next Quarterly
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    Analysis meeting
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Homework:
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- Alicia: confirm that tcoin.param cuts are applied correctly
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- Alicia: explore CT vs beta to see if cutting it makes much difference
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- Richard: confirm that get same behavior of CT vs MM (although Heep-Coin seems
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  already to show this)
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- Richard: compute Non-Gaussian correction both ways, and we will have to
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  decide which method is more reliable to apply to data
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GH checks logbook, and thinks the CT timing error was fixed by Brad on
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2018-Nov-15
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- https://logbooks.jlab.org/entry/3626796
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- https://logbooks.jlab.org/entry/3626194
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- This is during the SIDIS-CSV run between the 10.6 and 3.8 GeV KaonLT data
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  taking
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Next Meeting
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------------
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- Tues Oct 10 @ 15:00 Eastern/13:00 Regina/12:00 Pacific
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- PionLT will go first
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Join Zoom Meeting
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https://uregina-ca.zoom.us/j/94470211297?pwd=djBROEdWUENLUTF3ZFN1c0kvS0VIQT09
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Meeting ID: 944 7021 1297
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Passcode: 320362
(299-299/412)