August 2, 2010 (11AM), Physics Working Group

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Connecting to the Meeting

ESNET and EVO will be available:

1. ESNET: 85-42553 (85-HALLD)

2. An EVO room under GlueX will be reserved

3. Phone:

+1-800-377-8846 : US

+1-888-276-7715 : Canada

+1-302-709-8424 : International

then enter participant code: 77438230# (remember the "#")

Reference Material

In going back through old notes, the following documents were relevant in preparing the beam estimates that were presented in the 2006 PAC 30 Documentation. See section VI starting on page 19 which provides a nice summary of the following reference works. Looking back over these documents, the following assumptions were made in computing the number of events:

  1. 26 weeks of running per year with a factor of 1/3 for overall efficiency.
  2. Reconstruction efficiency is 72%.

The first assumption is probably reasonable. The second is probably a factor of about 2 too large. The conclusions of the study was that a 1 microbarn cross section would yield 4.5(107) events per year for each (107) of photon flux. Scaling this down, I would estimate about 2 (107) reconstructed events per year for the cross section.

The report goes on to examine three interesting final states \pi \pi \pi , \omega \pi \pi and \eta \pi \pi including decays. The money plot is Figure 5 in document 621 which should be scaled down by about a factor of 2.25. At (107) photons on target per second, we can easily do \pi \pi \pi . The other two channels probably require 2-3 times that beam rate for a year to accumulate sufficient statistics in the 2.0 to 2.4 GeV mass range in two years of running. In addition, while not examined in the note, the \pi \pi \pi \pi channel would also have sufficient statistics with the lower beam rates.

One then asks what do we need (108) photons per second for? The answer comes in the final states involving strangeness as well as rarer modes like \phi \omega that are interesting for some searches.

  • GlueX-doc-667 The First Two Years of GlueX Physics - C. A. Meyer, Talk (2006).
  • GlueX-doc-642 The First Two Years of GlueX Physics - C. A. Meyer, Talk (2006).
  • GlueX-doc-621 Potential GlueX Physics During the First Two Years of 12 GeV Running - C.A. Meyer, Report (2006).
  • GlueX-doc-438 A summary of expected event rates in GlueX - C.A. Meyer, Report (2005).