March 8, 2013 PID Upgrade

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Meeting Time and Place

Friday March 8, 2013 at 1:30pm At Jefferson Lab, the meeting will be held in F326


To connect from the outside, please use ESNET or SeeVogh

  1. ) ESNET: 8542553
  2. ) SeeVogh: A conference has been booked under "GlueX PID Upgrade" from 1:00pm until 3:00pm (EDT).
    1. ) To phone into an SeeVogh meeting, from the U.S. call (626) 395-2112 and then enter the EVO meeting code, 155025.
    2. ) To use the SeeVogh Java script use the SeeVogh link.


  1. Announcements
  2. Cherenkov EM Backgrounds (John)
  3. Recoil proton (Justin)
  4. AOB


Cherenkov EM Backgrounds:

  • Study of EM backgrounds in the forward gas threshold cherenkov
  • Pileup EM interactions added in the bggen generator and MC trajectories traced to the detector volume
  • Most background electrons at very forward angles (theta < 2) so this region was excluded
  • Conclusions:
    • 1 photoelectron threshold vetos ~99% of pions above 3 GeV (Question of what is PMT/electronics noise which may set the lower bound for the threshold, work on for next meeting)
    • 21% of events have a background electron producing cherenkov light in the detector which causes some kaons to be misidentified, but simple to overcome with multiple segments

Recoil Proton:

  • Study of eta'(2300) and h'(2600) channels with reconstructed recoil proton compared to previous missing proton analysis
  • Significant gains in both channels when the proton is reconstructed with up to S/B ~ 30, but efficiencies may be too low
  • For the next 2 weeks the focus will be on completing the analysis of the four channels from last year's PAC proposal with larger statistics
  • To study the case for the PID upgrade plan to apply John's toy model for the gas threshold detector to improve efficiency but maintain high purity
  • Also discussed studying channels with neutrals or a recoil neutron where the impact of upgraded PID may be more significant