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Kaon LT Meetings » mtg_23may18.txt

Garth Huber, 05/19/2023 05:14 PM

 
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                 May 18/23 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, Ali Usman, Muhammad Junaid, Alicia Postuma, Nathan
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   Heinrich, Love Preet, Vijay Kumar
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CUA - Richard Trotta
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Ohio - Jacob Murphy, Julie Roche
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JLab - Dave Gaskell
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CSULA - Konrad Aniol
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Nathan Updates
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--------------
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HMS Cherenkov Calibrations
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- Last week, DG asked to tighten up the fit range, new results shown
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- peculiarly, PMT1,2 gain parameters are anti-correlated for some run periods,
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  runs where PMT1 is high, PMT2 is low
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   - NH looked more carefully at Adc plots, everything seems okay, so the
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     effect appears real
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   - NH looked in logbook at time of outliers near run ~16250, nothing unusual
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     was noted
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   - DG: inclusive meeting on Wednesday (Cameron Cotton) sees something
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     similar, depends on what background is underneath the 1pe peak
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      - are all these at the same kinematics?  are different ranges of the
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        focal plane illuminated?
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      - NH: no, a variety of settings
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      - the inclusive group decided to choose the run with the cleanest
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        spectrum and go with it for those runs
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      - NH brings up a pulse integral plot, much less bkd than what inclusive
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        sees, DG agrees it looks pretty clean
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- Discussion on picking run ranges for parameters
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   - GH: try dividing runs into 3 groups:
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      - for PMT2, all runs with gain >9, two groups with gain <9
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   - error weighted means for the PMTS:
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      - PMT1: 10.2 (looks reasonable), PMT2: 8.8 (definitely too low)
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Next week: will also show initial results of NGC calibrations
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Junaid Updates
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--------------
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- no report, busy on Proton Structure class reports
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Jacob Updates
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-------------
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- no report, writing thesis
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   - hopes to have a draft of the optics chapter ready soon
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   - then will help Junaid with calorimeter calibrations
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Richard Updates
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---------------
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Carbon Lumi studies
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- plot of HMS relative Tracked Yield vs ELREAL rate for all Carbon runs
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   - used method suggested by GH to combine different settings by normalizing
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     each one to zero rate
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   - curve with combined settings is nicely consistent
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   - error-weighted fit:
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     get a slope of (2.1+/-0.995%)/100 kHz
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- plot for SHMS is similar, except that rate is up to 250 kHz
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   - slope is nicely similar (1.9%+/-1.0%)/100 kHz
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- *Next* RT should move to doing same with Physics Lumi study to see if results
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   are consistent
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   - analysis by PeterB indicates that this will be definitive in deciding
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     whether to apply a correction to the data
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Problem processing large ROOT files
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- met yesterday to discuss problem
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- RT will make changes to the python code
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   - inefficient memory usage caused by error in upRoot
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   - everythng now uses List data structure, can change to NumPy arrays
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   - if this doesn't work, then RT will try cache-ing
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Ali Updates
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-----------
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OOP offsets from Heep Coin, now that BPMs are fixed
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- using method from Tanja thesis Fig 3.11
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- Heep settings at 3.8, 4.9, 6.2, 8.2, 10.6 GeV are used
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   - data mean and errors from HMS, SHMS xptar plots
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   - at 10.6 GeV, the P_HMS=6.59 GeV/c, so deep into saturation region
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- DO NOT get a nice correlation like in TH thesis
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   - outlier at Pp/Pe=1.3 is low Q2 data, far from saturation
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  - DG: survey data indicate a fixed survey offset should work for both
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    spectrometers, so we need to understand this
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- GH notes that SIMC distributions also do not have xptar mean=0, so should
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  the difference between MC and data be used, instead of trying to move the
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  data mean to 0?
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   - DG: Yes, MC predicts a non-zero xptar, so this should be taken into
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     account
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   - subtract data-MC xptar
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   - SHMS xptar has a weird OOP acceptance, due to HB and other effects
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   - nonetheless, DG expects the method in Tanja's thesis should be totally
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     applicable here
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- AU: should he include the Summer 2019 data too?  Yes
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- DG: other effects.  If the beam position is changing, then would have to
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  throw away the data from that run.  i.e. that run would be good for all
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  purposes EXCEPT determining OOP offsets
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   - would need to enable EPICS variable tree in hcana
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   - make a histo of vertical beam position at target from BPMS 3H07A, 3H07C
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   - then extrapolate from these to the target
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- Summary of Suggestions:
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   - use data-MC xptar means
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   - look at BPMs to see if beam position is changing
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   - include two Summer 2019 settings to get more points
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- To avoid waiting for others, can look at PMx,PMz,EM from HeepCheck in
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  parallel, as these should be independent of OOP offset
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Vijay Updates
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-------------
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Raster for Summer 2019 data
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- checked raster correlations for all 3 beam energies
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- very small left slope is observed, consistent with what Ali found
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- DG will talk to MarkJ about this
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   - the Matrix Element fit is from single arm MC, so not surprising if a
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     little bit off
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   - the question is whether we should ignore the small slope or make a
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     correction to further improve things
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- working on HMS calorimeter efficiency study, will give results next week
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- then will do Lumi study on Carbon, similar to what RT showed today
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Alicia Updates
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BSA status update
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- looking at CoinTime to investigate effect of K+ contamination on pi+ BSA
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   - magenta: HGC cut, Red: MM cut, cyan: MM+HGC cuts
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   - HGC cut gets rid of most K+ but causes larger BSA errors (undesirable)
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   - MM cut gets rid of randoms
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   - MM+CT cut looks cleanest
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   - proposing a cut of ~2.25ns, and do a cut study +/-0.5ns to check cut
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     dependence on BSA result
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      - would quote the variation relative to 2.25ns cut as a systematic error
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   - CT, aerogel, calorimeter, MM cuts will be used
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      - HGC >2pe cut makes little difference
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- initial look at two new settings 
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  Q2=3, W=3.4  and  Q2=5.5, W=3.02
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   - tentative t-binning
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   - generally looks OK, but some t-bins need adjustment, so that statistics
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     are more equalized
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   - will co-ordinate with AU for common t-binning over kinematic range between
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    AU's diamond cut and AP's no-diamond cut
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- some further discussion about SIMC not properly reproducing the neutron peak
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  width at higher -t we observed 2 weeks ago
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   - DG says radiative model in SIMC has no free parameters that can be tweaked
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   - rather, sugggests that the wider peak width is due to piDelta final state
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     coming underneath the n peak at higher -t
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   - AP will look into simulating piDelta with SIMC to see if this is a good
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     explanation
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   - DG: PeterB's piDelta model is implemented in SIMC, will send the
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     appropriate flags by email
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   > To simulate the Delta in the final state in simc, the input file flags
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     should be set as usual for exclusive pion production, but there are
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     additional options for "which_pion":
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     which_pion = 2 ;  (0=p->pi+,1=n->pi-,10/11 for pi+/pi- coherent, 2/3 for pi+/pi- Delta final state)
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     For pi+ production, which pion should be set to 2. 
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Next Meeting
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------------
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- Thur May 25 @ 16:00 Eastern/14:00 Regina/13:00 Pacific
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- KaonLT will go first
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