Difference between revisions of "JEF meeting, August 27, 2021"

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(Minutes)
Line 55: Line 55:
 
** Background in 2η channel is high, but reduced by imposing a π0 veto
 
** Background in 2η channel is high, but reduced by imposing a π0 veto
 
** Handled background by looking at side-band regions in 2D
 
** Handled background by looking at side-band regions in 2D
 +
** See considerable 2π0 strength at low mass consistent with f0(500)
 +
** We had a discussion regarding simulation of these events
 +
*** Annika currently using genr8, looked into using amptools without much success
 +
*** Use mass distributions from data?

Revision as of 10:36, 30 August 2021

Meeting time and location= 9:30 am EST (JLab time) Bluejeans only


Connection instructions

We are using BlueJeans Video/Audio conferencing. Our meeting ID number is 992533564. Click "Expand" for more details.

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  • If connecting via Phone: Dial one of the following numbers and then enter the meeting ID above and hit "#" or "##"
  • If connecting via Polycom unit:
    • Dial 199.48.152.152 or bjn.vc
    • Enter meeting ID above

Agenda

  • SICCAS crystals
  • Module fabrication
  • COMCAL tests, TAC running, etc.
- Adjusting LED system for CCAL -- Sasha
  • Data analysis
- 2π0 and 2η studies -- Annika Thiel
- \eta \to \gamma\gamma\pi^0
  • Simulations

Minutes

Attendees: Bill B., Olga, Phil, Zisis, Arshak, Jon, Susan, Azizah, Igal, Annika, Liping, Sasha, Jane, S.T.

  • SICCAS received shipment of new raw material, producing test crystals now; plan to wait ~2 weeks for results
    • Powder from previous vendor --> poor quality crystals
    • Delivery schedule is still unknown
  • COMCAL has been installed on platform and re-surveyed
    • Still tilted but not as badly as before
    • Sasha checked out COMCAL response using LED and alpha source
      • LED response using amplitudes wider distribution than expected (hoped for?)--> spread in light distribution
    • Adjusted HV, checked timing --> things are starting to look good
  • Light uniformity from LMS is a concern for FCAL-II; plan to use different LED colors just like done for FCAL
  • Fernando has prototype for PMT divider for NPS, working on tuning design for them, then for us
    • Hope to test during upcoming runs, can even be during CPP next year, but want to set a deadline for the middle of next year
  • Igal gave an update on his η→π0γγ analysis
    • Ran simulations for both GlueX and JEF conditions
      • Observed considerable peaking background from η→2γ, probably arising from conversions/split-offs
        • Looked at ways to reduce or eliminate this contamination
    • Found expected number of π0γγ events to be roughly consistent with the JEF proposal
    • Found the amount of beam time needed for production of 50M ηs with recoil proton required to be roughly an order of magnitude longer than the proposal estimate
      • Factor of 4 discrepancy found after the meeting (?)
    • Found that the kinematic fit is distorting the mass distributions (sometimes moving peaks away from the physical mass values)
    • TMVA results briefly touched on, but signal after applying cut on BDT response seems high
  • Annika presented some results of her γp→p2π0,p2η analysis
    • Background in 2η channel is high, but reduced by imposing a π0 veto
    • Handled background by looking at side-band regions in 2D
    • See considerable 2π0 strength at low mass consistent with f0(500)
    • We had a discussion regarding simulation of these events
      • Annika currently using genr8, looked into using amptools without much success
      • Use mass distributions from data?