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Jan 9/25 PionLT/KaonLT Analysis Meeting Notes
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(Notes by GH)
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Today: PionLT will be discussed first
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Present
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Regina - Garth Huber, Ali Usman, Alicia Postuma, Nathan Heinrich,
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Nacer Hamdi, Vijay Kumar
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Ohio - Julie Roche
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JLab - Dave Gaskell
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Virginia - Richard Trotta
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FIU - Pete Markowitz
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Nathan
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------
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PionLT luminosity studies
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- plots of singles scaler yield vs current and rate
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- correlation with rate is much clearer than vs current
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- HMS scalers give nice straight line vs current
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- ELLT checks done, now get 2.8%/100uA slope for LH2 boiling
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- apply this boiling corr to SHMS, HMS scaler yields and replot vs rate
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- get a slope of 3.8%/MHz, consistent for both HMS and SHMS
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- interestingly, without the LH2 boiling correction, the HMS has a different
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rate dependence due to the lower rates at high current. When the LH2
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boiling corr is applied, HMS and SHMS look pretty consistent
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- *NB* need to confirm whether 3/4 or ELREAL rate is used on x-axis
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- took difference of global fit slope and individual settings, with statistical
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error removed in quadrature, as an estimate of the systematic uncertainty
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- obtained +/-0.7%/MHz
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- *NB* will apply this rate correction to Carbon Lumi data to confirm there is
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no anti-boiling
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- can adjust low current offset slightly if needed if anti-boiling is found
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- Dave: this suggests there is a source of DeadTime that we're missing
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- we see it in scaler analysis, so it would have to be in the trigger legs,
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not FADC or CPU
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- most likely culprit would be the 3/4 trigger
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- *NB* Carlos did find some anomalously high DeadTimes, Dave Mack did a
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study in response.
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Take a look at:
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1. Dave Mack's presentation on explaining the larger than expected dead
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time from Carlos' data:
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https://hallcweb.jlab.org/doc-private/ShowDocument?docid=1063
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2. Casey's application of this calculation:
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https://misportal.jlab.org/ul/publications/downloadFile.cfm?pub_id=20620
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Page 88 or so.
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- Julie: in your plot vs rate, is there any indication of a flat part at low
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rate?
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- need to recheck low current offsets first
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- don't think the evidence is compelling
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- Coin Lumi vs rate and vs current
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- *NB* plotted vs COIN rate, but if the DeadTime is in the trigger leg, it
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needs be the equivalent 3/4 rate integrated over both arms
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- expecting studies to be wrapped up in 1-2 weeks
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- *NB* Richard, Vijay should apply Nathan's rate dep to their Lumi data and
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see what they get
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Alicia
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------
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BSA revisions, PLB vs PRC
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- journal length limits are very different
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- will prepare revisions assuming PLB and then see if can address the referee
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comments in that limit, or if we need PRC length instead
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Nacer
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-----
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KaonLT yield scripts
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- found that MM is shifted ~50 MeV compared to SIMC
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- still trying to figure out what is wrong
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- Garth: suggests to start by checking standard.kinematics, since it must be
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something substantial
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- *NB* Ali (better suggestion): maybe there is a typo in the kinematic
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offsets, and they are off by an order of magnitude
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- *NB* Garth: suggests to compare to online MM plots at
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https://hallcweb.jlab.org/wiki/index.php/Kaon_LT_Status_Page#Kaon_LT_Physics_Status_at_Ebeam_.3D_3.8.2F4.9_GeV
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- these were generated with the online version of standard.kinematics, so the
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comparison might eliminate some possibilities
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- online analysis script integrated a region around the Lambda MM so it would
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have been noticed quickly if the Lambda peak was shifted by 50 MeV then
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For the rest of the meeting, we reviewed draft presentations by Richard and
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Vijay
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Next Meeting
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-------------
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- Thur Jan 16 @ 16:00 Eastern/15:00 Regina
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- KaonLT will go first
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- we also need to check if people's availability has changed after Jan 16, or
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if we can keep this time until daylight savings time change in March
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