Difference between revisions of "Pi0 Polarizability Meeting Jan 17, 2020"

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# Other business
 
# Other business
 
#* Rory pointed us to a new paper by Vanderhagen and collaborators on gamma*gamma*->pipi. He will make contact with Marc and/or Danilken to see if they can extend the calculation to the threshold region. He will prepare a couple of slides for discussion at our next meeting.
 
#* Rory pointed us to a new paper by Vanderhagen and collaborators on gamma*gamma*->pipi. He will make contact with Marc and/or Danilken to see if they can extend the calculation to the threshold region. He will prepare a couple of slides for discussion at our next meeting.
# Next meeting
+
#* [http://arxiv.org/abs/arXiv:1909.04158  arXiv:1909.04158]# Next meeting
 
#* Friday, Jan 31, 10 am
 
#* Friday, Jan 31, 10 am

Revision as of 13:03, 17 January 2020

Meeting Information

Meeting Time And Location

10:00 am ET (JLab time)

CC F228

Connecting

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Action Items

  1. ChiPT calculation to one loop with Coulomb photon (Svetlana and Aleks)

Tentative Agenda

  1. Announcements
  2. Action Items
  3. Theory update
  4. Experiment update
  5. Other business
  6. Next meeting

Minutes

Attending: Aleks, Elton, Mark, Joe, Alex, David, Rory.

  1. Announcements
    • Aaron Bernstein passed away recently.
  2. Action Items
    • The Compton scattering amplitudes for real photons has been completed. Planning to do the calculation for one off-shell photon.
    • Jose's analysis indicates that the effect of the photon virtuality is very small.
  3. Theory update
    • Jan 17 Update
    • Section 3.2 Compton Amplitudes A, B are needed.
    • Use the pi-pi phase shifts to determine date f0 and f2 dispersive parts.
    • The t and u channel resonance contributions are also needed.
    • The Omnes function also needs a cutoff >~ 1 GeV. Using this value four subtraction constants are determined using the measured cross section near threshold.
    • Still need an error analysis to determine uncertainty in polarizability parameters from theory.
  4. Experiment update
    • Elton has resurrected the program to generate and analyze the pi0pi0 reaction, which was used for the LOI. The updated software uses GEANT4, which we will be needed going forward especially for CPP (to include muon chambers). The software also has merged all updates to the GlueX analysis to make it current. These updates show there are no major differences between GEANT3 and GEANT4. Some small differences are not unexpected. See information in the files below.
    • Reproducing LOI output using GEANT4 (Elton)
    • Updates to processing
    • DSelector output for signal
    • DSelector output for flat
    • AmpTools output for fit
  5. Other business
    • Rory pointed us to a new paper by Vanderhagen and collaborators on gamma*gamma*->pipi. He will make contact with Marc and/or Danilken to see if they can extend the calculation to the threshold region. He will prepare a couple of slides for discussion at our next meeting.
    • arXiv:1909.04158# Next meeting
    • Friday, Jan 31, 10 am