Pi0 Polarizability Meeting Apr 17, 2020
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Contents
Meeting Information
Meeting Time And Location
10:00 am ET (JLab time)
REMOTE
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Action Items
- ChiPT calculation to one loop with Coulomb photon (Svetlana and Aleks)
- Follow-up contact with Marc to request paragraph (Rory)
Tentative Agenda
- Announcements
- Action Items
- Feedback from collaboration review
- Feedback from Barry / Tue Apr 14
- Rory: The estimate of the incoherent is not easy, but should be uniform in Phi, so polarization is a valuable tool.
- Feedback from Joerg
- We need to clarify that CPP will run with a Pb target and we need an estimate of the calorimeter trigger rate to insure that NPP can run concurrently with CPP. Ilya was volunteered for this task.
- Feedback from Barry / Tue Apr 14
- Theory update
- Experiment update
- GlueX-doc-4433 Eta background (Elton)
- Updates to collaboration draft
- Backgrounds to be simulated
- Background hits
- BGGEN (PYTHIA)
- eta production (Elton)
- Incoherent production (Elton)
- Npipi
- Table of cross sections (Rory and Ilya)
- Include references to relevant data
- Add values used in the proposal
- Experiment optimization
- Target position (Beni).. not yet
- Primex He4 first look: Media:npp_primexdata.pdf
- NPP MC test with 6 and 8 GeV Beam energy: Media:npp_MC.pdf
- Generate angular distributions for some other targets to compare to Pb
- Target position (Beni).. not yet
- Significance of experiment
- The expected uncertainties of the extracted gg->pi0pi0 cross section (Fig. 24 of proposal) need to be verified and studied more carefully
- Analysis of PRIMEX data
- Backgrounds to be simulated
- Other business
- Next meeting
Minutes
Attending: Jose, Svetlana, Beni, Ilya, Rory, Alex, Mark, Elton.
- Announcements
- Action Items
- Feedback from collaboration review
- Theory update
- Discussion with Serguei Gevorkyan / Mon Apr 13
- The plan for additional theory requires substantial work. The precision that the polarizability may be extracted with a given cross section uncertainty is still a goal for Jose and Svetlana, but will take time. For the proposal, the will rely on the Dai/Pennington calculations. Calculations to improvements in the extraction will continue past the proposal submission.
- Experiment update
- GlueX-doc-4433 Eta background (Elton)
- Rory: It would be nice to plot the elasticity, in addition to missing mass, for ease of comparison with other Primakoff experiments.
- Many questions and discussion occurred during the presentation.
- GlueX-doc-4433 Eta background (Elton)
- The remaining part of the agenda was left tabled for Monday. Here are some notes from meeting on Monday Apr 20:
- Primex He4 first look: Media:npp_primexdata.pdf
- Beni showed various distributions of interest, especially the 2pi mass spectrum with various cuts.
- He finds that the energy balance cut is a key discriminator for background
- NPP MC test with 6 and 8 GeV Beam energy: Media:npp_MC.pdf
- Running the gen_2pi0_primakoff generator, Beni compared the output at 6 and 8 GeV, with various interesting results on angle and 2pi mass. Differences in the distributions are clearly visible; more work is needed to determine their effect on the final outcome of the experiment.
- Primex He4 first look: Media:npp_primexdata.pdf
- Other business
- Next meeting
- We will meet at 9:00 am on Monday to continue with Beni's presentation and discuss the strategy for completing the proposal.