JEF meeting Jul 13, 2015

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

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Agenda

• Task list updates
• η→3γ [Dave]
• Size of PWO Insertion in FCAL-II; [Liping]
• Tulin's talk at Patras Workshop

Minutes

Attendees: D. Dutta, L. Gan, M. Kamel, B. Karki, D. Mack, J. Roche, A. Somov, I. Strakovsky, S. Taylor, J. Stevens

• Ilya has obtained the hybrid version of simulation/reconstruction code and will work on implementing the island code in this context. Next step is to make a factory for reconstruction of FCALI/II hits using reconstruction algorithm.
  • Web page with some details about Ilya's code
• L. Gan gave a brief update about the insert.
  • A 60x60 cm^2 insert as a starting point appears to already part of the plan (radiation hardness)
  • Liping looked at effect of background for hybrid in the η→π0γγ channel due to η→3π0 as a function of insert size.
    • Eγ=9-11.7 GeV; 3σ cuts for invariant mass and ΔE; parametrized position resolutions for lead glass and lead tungstate
    • FOM=S/sqrt(B) increases with insert size: 120x120 cm^2 is about 2.5 times better than 60x60 cm^2
• Liping reported that Eugene talked to Rolf regarding a small-scale (20 crystal) prototype.
  • Hall C has already purchased several crystals -- arrange to share?
  • Length has not been optimized yet (Primex length 18 cm vs 20 cm for Hall C; may need to make the face larger than Hall C's 2x2 cm^2 to accommodate shielding for PMT).
  • Sasha contacted Hamamatsu about PMTs -- no word yet?
  • DM suggested should get engineer to simulate magnetic shielding for expected conditions for insert
  • Calorimeter could in principle be moved further downstream...
• Dave showed some slides regarding the impact of η(')→3γ based on some early work by Tarasov.
  • Probe C-violating/Parity conserving amplitudes.
  • Ratio of BR(3γ)/BR(2γ) depends on (unknown) loop mass -- if loop mass ~ m_π, a tight constraint can be obtained; if loop mass ~ m_ρ (for example) this decay is not interesting...
  • Should ask theorists to revisit η→3γ
• Liping highlighted some slides from one of Tulin's workshop presentations on astrophysics.
  • Self-interacting dark matter may resolve some astrophysical discrepancies associated with cold collision-less dark matter -- may have implications for our B-boson search?