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Kaon LT Meetings » mtg_24jun06.txt

Garth Huber, 06/06/2024 07:18 PM

 
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                 Jun 6/24 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, Muhammad Junaid, Ali Usman, Nathan Heinrich, 
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   Zach Sullivan, Nacer Hamdi, Vijay Kumar
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York - Stephen Kay
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CUA - Casey Morean, Tanja Horn
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Virginia - Richard Trotta
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CSULA - Konrad Aniol
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Nathan and Zach
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---------------
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PionLT Luminosity Studies
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- Zach now has Nathan's scripts working in his account
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- Carbon HMS Runs 16727-16737
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  - Accept/Total scaler count is low for <15uA, will need to change current
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    cuts for low current runs.  Then will need to recheck low current data
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  - CPULT is very low ~81%, while TLT ~98%
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    - Richard: suggested looking more carefully at what trigger is used
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    - Nathan: things using ELREAL instead of ELCLEAN, will check
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- LH2 HMS Runs 16703-16712
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  - Again a problem w/ CPULT ~79%
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  - No boiling seen up to 60uA, then suddenly down to 92% at 80uA (no Track),
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    same for Tracked analysis
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  - Scaler analysis looks good however
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- Carbon SHMS Runs 16738-16746
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  - CPULT looks good, gives hint on what may be wrong for HMS analysis
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- LH2 SHMS Runs 16759-16764
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  - boiling looks better here, so need to look again at HMS, they should be the
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    same within errors
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  - Scaler analysis: 98% at 80uA
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  - No-Track: 95% at 80uA
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  - Track: 94% at 80uA
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- Next Steps:
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  1) Zach will work on code for Efficiencies for PID cuts used in analysis
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    - will look to see if there is any rate dependence
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  2) Look at what trigger is used for CPULT calc
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  3) Adjust hcana current cuts for low current runs
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  - then replay data and look at results
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Junaid
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------
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PionLT Detector Eff Study
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- runs with HMS p<4.2 GeV/c
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  - Cer_eff uses npeSum >1.5 cut, tighter cut on Calorimeter
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  - Cal_eff uses tight cut on Cerenkov instead
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- Obtain CerEff=0.9981 CalEff=0.9981
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  - KaonLT had CerEff much less than CalEff: CerEff=0.9717 CalEff=0.9929
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  - interesting that CerEff are so different between the two experiments
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  - Tanja: when you applied tight cut on Cerenkov, did you do that to define
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    the sample on the calorimeter?
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  - Ali: CerEff is likely different from KaonLT due to different cut value used
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    (1.5 vs 2.0 npe).  KaonLT used nepSum>2 because that was needed in the
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    Physics analysis.
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    - *NB* You should do a quick check of 3-4 physics runs at
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      different settings to make sure you don't need a higher cut
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PionLT Heep Study
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- finalized OOP offsets, corrected beam energies
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- there was some confusion on implementing momentum offsets
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  - verified how the offset is applied in hcana, offsets need to be entered as
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    %P.  This means the P-offsets applied by Vijay are not done correctly.  The
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    effect will be small since his P-offsets are small, but should be checked
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    as a systematic.
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- Heep comparison plots (before vs. after offsets)
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  - PMZ, EM worse
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  - PMX, PMY, W improved
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    - Richard: similar behavior to what he saw
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    - confirmed that simc-reconstruction script was used
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- Table of shifts between Data and SIMC (after offset vs. expected)
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  - PMZ shifts in opposite direction than predicted by GH's program
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  - need to look closer at whether to ADD or SUBTRACT offset
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  - *NB* Garth: The HeepCheck program says dp_m(par) is correlated only with
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    dp_p so the sign of the dp offsets should be checked
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Vijay
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-----
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- Met with Richard, Ali yesterday to discuss systematics, Richard will give
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  more details
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  - Vijay is working on MM Cut-Dep study
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    - will modify cuts by +/-2,4,6,8 MeV from standard 980 MeV MM cut
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    - needs to subtract obtained cross section from that obtained with standard
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      cut and tabulate the differences vs. t-bin
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Richard
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-------
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- gives some info on using Globus for file transfer from JLab
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KaonLT LT-separations
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- simplified the functional form for sigL, sigT:
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  - sigL=(p1+p2*log(Q2))*exp(p3*|t|)
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  - sigT=(p5*(|t|/Q2-1)*exp(p6*|t|)
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- after 1 iteration, sigT did not change too much for Q2=3.0, W=3.14, so
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  optimistic that on right track
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- tried to work on Q2=2.1 L/T-separations
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  - the low epsilon diamond is quite small, corresponding to a relatively large
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    delta-epsilon
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  - this means there will be smaller error magnification for sigL, but at the
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    cost of low epsilon data have poor statistics.  Hopefully they will balance
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    out in the final analysis
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  - low epsilon stats are too low to be sure the functional form is good, etc.
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  - will go to higher Q2 and then work down from there
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Summary of Random Systematics Discussion w/ Ali, Vijay
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Acceptance - vary geometrical cuts
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PID - vary PID cuts
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  - HGC will drive K+ studies
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  - separate studies needed here for every analysis, since backgrounds and cuts
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    vary
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Tracking - compare effs for different algorithms, tracking parameters
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Kinematics - adjust offsets
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Radiative Corr - turn on/off radcor flag in SIMC
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Model Dep - vary input model
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  - Garth: in pi-/pi+ analysis we set LT=TT=0 and extracted new cross sections
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    without iterating
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  - Tanja: Fpi-2 took a more gentle approach, used different models with
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    iterating
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Nacer
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-----
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KaonLT Heep Study
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- presented Data and SIMC cuts, corrections for 2 beam energies
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- 3.8 GeV Data/MC Yield ratio = 1.02 +/- 0.005 (stat)
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- 4.9 GeV ratio = 1.046 +/- 0.004
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  - both results very similar to Richard's, although analysis is different
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  - *NB* Ali: The CerEff is calculated for >2npe cut, while Nacer is using
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    >1.5npe cut.  The cut and efficiency need to correspond to each other, so
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    this needs to be checked.
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  - We see from Junaid's results that the difference in CerEff is about 3%, so
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    this might explain most of the ratio difference from Unity.  Nacer and
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    Junaid will discuss.
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Ali
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---
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piDelta MM Shape Study for additional settings
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- Q2=3.0, W=3.14
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  - exluding (t,phi) bins from fit if low statistics or if MM fit fails
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  - Center SHMS, high -t: Two bins (135<phi<180, -180<phi<-135) have no piDelta
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    contribution from MM to Data, are excluded
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  - The data for these two bins are mostly at higher MM, only a small fraction
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    of events near Delta MM
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- Q2=2.1, W=2.95
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  - two t-bins: 0-0.27, 0.25-0.55.  Higher -t data are excluded 0.55-1.0
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- Will have BSA soon for all 5 settings
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  - then will compare LT' to Alicia's pi+n (rebinned) and CLAS pi-Delta++
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- Also did some systematic uncertainty studies, both related to MM fit
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  dependence
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  - MM cut dependence is yet to do
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 Next Meeting
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------------
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- Next meet: Thur June 13 @ 15:00 Eastern/13:00 Regina
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  - KaonLT will go first
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