JEF meeting May 18, 2015

Meeting time and location= 13:30 EST (JLab time) CC F326-327

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Agenda

• Participation by U. Santa Maria?
• γp→pη, η→π+π-π0 -- Dave.
• Meeting day and time?
• Path to PAC44, -- Liping

Minutes

Attendees: D. Dutta, L. Gan, H. Hakobyan (+Orlando), M. Kamel, D. Mack, M. McCaughan, A. Somov, J. Stevens, S. Taylor

• H. Hakobyan (U. Santa Maria) has a new student that could work on JEF-related projects.
• Dave Mack presented some studies related to understanding the η→3π channel. He has been comparing Justin's results from the recent run with studies done by Ryan Mitchell. We have very limited statistics from the currently available data sets (and there's no visible η peak at all in the π+π-π0 channel...). The background seems to be higher than expected, so one of the main tasks is to try to understand this background. These could include extra π0's, mis-identified protons, and the like. One of the tools in our arsenal is kinematic fitting. Justin has been using this but has not been constraining the π0 to go to 2γ and it is not clear that we understand the errors well enough yet. Dave suggested a few additional cuts we could apply while this is being improved, including restricting the momentum of the recoil proton to below 1 GeV/c and cutting on the numbers of showers and tracks in the event.

• Liping started the discussion about how to address the PAC's concerns before we go back to the PAC next year to get the conditional part of the approval lifted.
  • We must demonstrate that we can run in parallel with the regular GlueX program (using coherent bremsstrahlung beam).
    • The assumptions are that the Hybrid calorimeter would be in place, but also the DIRC would be in front of FCAL-II. Running MC studies with the Hybrid calorimeter geometry is one of the highest priorities. We should look into studying how the GlueX program itself could benefit from the insert. We would also like to test I. Larin's island algorithm with a realistic simulation.
    • A careful study of the impact of accidentals on the rare-decay part of the program is needed. The coincidental tagger rate in the 9-11.7 GeV beam photon energy range under GlueX Phase-IV conditions is a factor of 2 worse than the JEF proposal.
  • Some more effort in strengthening of the theoretical motivations for the program is needed. Liping has been in contact with M. Ramsey-Musolf, who has a student working on beyond-SM physics that may be accessible via eta decays. S. Tulin may also have a student that can work on the B-boson physics.
  • We are moving forward with plans to build a small-scale prototype for the lead tungstate insert for studying the properties of PW04 crystals we plan to obtain from the Shanghai Ceramic Institute.
  • A task of lesser importance is to beef up the eta-prime part of the proposal.
  • We should plan to have something substantial to say by the next GlueX collaboration meeting in October.