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Kaon LT Meetings » mtg_24aug29.txt

Garth Huber, 08/29/2024 07:25 PM

 
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                 Aug 29/24 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, Alicia Postuma, Ali Usman, Nathan Heinrich, 
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   Muhammad Junaid, Vijay Kumar, Zach Sullivan, Nacer Hamdi
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York - Stephen Kay
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JLab - Dave Gaskell
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FIU - Pete Markowitz
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CUA - Casey Morean, Tanja Horn
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Virginia - Richard Trotta
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Nathan & Zach
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-------------
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PionLT Lumi studies
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- last week it was discussed using TLT from CPULT & ElLT instead of EDTM
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  - ElLT calc from 55ns*(Total Rate)
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- Plots  Red: EDTM  Blue: CPU method
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  - SHMS Carbon Runs 16738-16746
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    - w/EDTM, a small yield rise w/current, 2 outlier runs
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    - CPU method: LT used if it disagrees w/TLT >1 sigma
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      yield is flat within errors
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  - HMS LH2 Runs 16703-16712
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    - CPULT~80%, must be an issue with how it is calculated
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    - Dave: *NB* you can infer the CPULT from other info in the report file
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      - it should be #ADC-events/PreTrig-Scaler-events
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      - maybe the calc is pointing to the wrong PreTrig
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      - can calculate by hand to check
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- quickly runs through slides for next week's Quarterly Analysis Mtg on BCM
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  calib, looks good
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Junaid
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------
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PionLT SHMS-3/4 Hodo Effs
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- some runs have low eff ~85-87%
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- plots of single plane eff vs 3/4-Trig-Rate and S1X-Hodo-Rate
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  - 1st plane: ~99%
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  - 2nd plane: one set at 95-96%, and other at ~98%
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  - 3rd plane: two trends: flat at 78-82%, exp drop 98-80%
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  - 4th plane: two trends: flat at 80-90%, lower trend 65-70%
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- Dave: *NB* suggest plot of Eff vs Momentum
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  - quartz bar effs are lower at low momentum
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    - makes it difficult to test 3rd plane eff when 4th plane inefficient
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- Dave: *NB* check the slop parameters in hcana on track projection to planes
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  in param file
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  - assumes there is a valid trigger and a vaid track
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  - looks at each plane in succession and uses track selection to find out
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    which hodo bar should have been hit, and then checks if that hodo fired
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  - maybe the track is pointing to the wrong hodo due to multiple-scattering
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  - if the track slop parameter is too tight, then the hodo is not counted,
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    leading to a too-low efficiency
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- Dave: *NB* it would be helpful to see if there is a version of this
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  efficiency calculation with PID cuts
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  - i.e. in the 6-GeV era, we had multiple calculations of efficiencies:
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    overall, pions only, protons only, electrons only
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  - not sure if this was carried over into the 12-GeV era code or not
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- Dave: *NB* checks the code and finds there is a hardwired Cherenkov cut in
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  the hodoscope efficiency calculation, CERCUT
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  - it might be inappropriately set
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  - if this cut value is changed, hcana needs to be recompiled
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- SHMS_Hodo-S1XY, S2XY effs are much higher, >90%
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  - Dave: these were for an STOF OR test, not so relevant anymore
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PionLT HeeP
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- data have pi0 contribs
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  - calculate Exp/MC ratio w/ and w/o pi0 cut, MM<0.1 GeV
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  - 8.5 GeV data: Ratio goes from 1.136 (w/o cut) to 1.028 (w/ cut)
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  - implemented Ali's Drift Chamber resolution param in SIMC for this analysis
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Nacer
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-----
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KaonLT HeeP
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- looking at 8.2 GeV data, which have worst Exp/MC ratio
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- ElLT calc:
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  - using 55ns*Rate >99.9%, where HMS-ELREAL+SHMS-3/4 ~ 4kHz
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  - using ElLT from EDTM and CPULT: 95.6-99.6%
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- EDTM: R=1.126+/-0.006  w/ElLT: R-1.111+/-0.006
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- MM comparo
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  - Change resmult=1.0 to 3.5 (Ali's resolution smearing parameter adjustment)
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  - delta vs MM for SHMS, HMS
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    - data shows a wider region (delta<0 SHMS, delta>0 HMS) than SIMC
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- pi0 background, place conservative cut >0.11 GeV, could have used >0.10
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  - with resolution tuning but no MM cut, still get an extra bump in delta
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  - add MM>0.11 cut, the data-MC overlap is much better
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  - R-1.027+/-0.006
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- Ratios for the other Heep runs:
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   3.8: 1.000 +/- 0.004
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   4.9: 1.001 +/- 0.004
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   6.2: 1.019 +/- 0.004
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   6.8: 1.027 +/- 0.006
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  10.6: 0.930 +/- 0.005  w/o MM cut: R=1.043
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- Overall, very good news, things much better than before!  Well done Nacer!
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- GH: *NB* should investigate some MM cut dep
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  - *NB* should also look at applying a proton absorption correction 
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    (John Matter's spreadsheet, but need to adjust cross section for specific
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    momentum)
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  - *NB* finally, need to estimate the systematic uncertainty in the Ratio, it
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    won't change the Ratios themselves, but it will change the significance of
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    the deviation from 1, and help establish our overall systematic uncertainty
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    - this would include not only the systematic in the Exp yield, but also the
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      systematic in the SIMC yield (Nacer already determined this is higher at
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      10.6, from elastic model dep)
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- Discussion about using old HMS Matrix Elements
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  - Dave has found a systematic improvement between Data and MC comparison in
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    XEM data when using 6-GeV era matrix elements (ME)
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    - apparently these ME are not in the standard distribution, Dave had to
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      find them from older code
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  - it sounds worthwhile to check this with the Heep data, and if it is better,
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    then we should also use it for the physics data (both KaonLT and PionLT)
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  - *NB* Dave will send more information on what file to use
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Richard
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-------
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Q2=4.4 LT-separations
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- in a separate meeting, Dave had suggested to recheck recon_hcana calculations
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- plots of xptar vs yptar, all cuts applied, for SHMS, HMS
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  - also: delta vs delta
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  - agreement of shapes between data and MC seems reasonable, although there
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    are some binning issues with the data which hopefully will be fixed with
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    improved plotting
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- Some weird results last week were due to SIMC using a different
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  parameterization than the iterations, so params in one set of eqns did not
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  work in the other set
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  - that is fixed now, things starting to improve
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  - the issue, however, is that ratios get stuck ~0.4-0.6 for all Q2
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    - Garth: strongly feel there is still an inconsistency in the code
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      somewhere, Ratios must converge to 1, if the function is wrong, there
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      will be weird shapes to the ratios centered around 1
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    - the good news appears to be that the bug seems to be the same for all Q2,
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      so if Richard finds it once, it should be good for all settings
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  - Vijay does not recalculate SIMC weights, he reruns SIMC every time, so
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    checking against Vijay's version of this code is not very meaningful
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    - *NB* Vijay can meet with Richard later next week, probably Thursday
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  - will do a full replay of all data, including HeeP, to reproduce Nacer's work
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Ali, Alicia, Vijay
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------------------
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- no report this week
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 Next Meeting
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- Thur Sept 5 @ 16:30 Eastern/14:30 Regina
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  - KaonLT will go first
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  - *NB* Please note the new time and new Zoom ID!
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