JEF meeting, August 13, 2021
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Meeting time and location= 9:00 am EST (JLab time) Bluejeans only
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Agenda
- SICCAS crystals
- Module fabrication
- COMCAL tests, TAC running, etc.
- Data analysis
- Simulations
- Meeting time
Minutes
Attendees: Varun,Igal,Joanna,Zisis,Arshak,Chase,Liping,Sasha,Azizah,Bill B.,Tim B.,Jane,Jon,Phil,Olga,Susan,Jane,S.T.
- No update from SICCAS regarding test samples for production of new crystals
- Procedure for wrapping crystals has been updated (presented by Joanna(UNCW)): [1]
- Crytur confirmed can produce crystals (want to be fully loaded)
- COMCAL has been installed in the hall
- Light monitoring system: all channels checked, some channels were unstable (drifting amplitudes, due to poor connections on PMT socket?)
- Two channels replaced, some optical fibers reglued
- Found problem with one of 5 thermal sensors, will operate with 4
- About to move to platform for positioning on beam line
- Light monitoring system: all channels checked, some channels were unstable (drifting amplitudes, due to poor connections on PMT socket?)
- Chase presented update on using TMVA for background suppression for η→π0γγ channel
- Compared Boosted Decision Trees (BDT) to Fisher discriminants
- 15 input variables: tested various combinations
- BDT works better than Fisher
- Igal looked at applying BDT to simulations of signal (η→π0γγ) and background, and to 2017 data
- Looking at γp→4γ
- Vetoed 2π0, ηπ0 and 2η channels using 5σ cut
- Required all photons in FCAL and a fiducial cut to avoid getting too close to beam hole
- Monte Carlo: found large peaking background due to η→2γ
- Not reported by previous experiments -- need to understand source
- Using 4-vectors after kinematic fit sharpens features in mass distributions
- Apply cut on BDT greatly reduces background below signal region
- Jon briefly showed the z-positions where conversions of photons occur as part of a presentation about using MCTrajectory information from the simulation