Weekly Minutes 2008-08-08
From PrimExWiki
At JLab: Pawel Ambrozewicz, Ashot Gasparian, Mark Ito (chair), Subhash Khanal, Yelena Prok
On phone: Dan Dale, Tulio Rodrigues, Dan Sober
See the meeting page for the agenda.
Contents |
GlueX Monte Carlo work
Work is progressing. Beni Zihlmann of Hall D is working on the geometry for the lead tungstate insert. He has also implemented a scheme where the list of particles, and their momenta, impinging on the front face of the standard GlueX forward calorimeter are written to the Monte Carlo output.
Collaboration Meeting
Again, no change in plans. Current thinking is to have the meeting in the second part of September.
Paper Status Review
Pion lifetime paper
Dan D. and Aron are collaborating on a first draft. Outlines have been exchanged. Dan presented his outline and collected comments. Dan and Aron will get together and sharpen the definition of their roles in this effort.
Photon flux paper
Dan D. presented recent work by Alexei on a comparison of measurements versus simulation of the effect of the insertion of the experimental target on the absolute tagging ratio for various photon energies. The deviations are of order a percent. These are mainly a validation of the pair production cross section included in GEANT and are consistent with statements from the GEANT documentation; the lifetime result depends only weakly on this agreement. Dan initiated a discussion on whether it should be included in the paper. Dan will go ahead and put it in, but its inclusion may be raised again later.
Compton Differential Cross Section
Pawel explained how we can take the angular distribution of Compton events where we do not distinguish the electron from the photon (veto not used) and convert that to a measurement of the photon angular distribution, as is usually calculated in textbooks. See his webpage for the transformation formalism.
Measuring the Components of the Inelastic Cross Section
Tulio presented recent work he has done calculating and comparing the cross section of incoherent pion photoproduction and the cross section for omega production times the branching ratio for the decay 
. These were presented as a function of the x = Eπ / k for different angles in the lab of the pion and for both carbon and lead targets. He proposed that we look at the data inelastic data to observe the contrast between these two sources of pions and to confirm the calculation of their absolute rate.
Next Secretary
Pawel will record the minutes next time.
Recorded by Mark Ito
