Π polarizability Meeting Nov 2, 2012
We meet via Skype. The relevant Skype user names are:
- Rory Miskimen - rmiskimen
- Alexander Mushkarenkov - alexander_mushkarenkov
- Elton Smith - eltonssmith
- David Lawrence - aehsdad
some phone numbers if needed:
David: (757) 269-5567 Rory: (413) 545-2480
Attendees: Rory M. (chair), David L., Sascha M.
- Contacted Richard Jones about beam polarization optimization. Received long e-mail in response with lots of info.
- FOM to optimize polarization will include polarization^2 times event rate
- Need to get correlation between polarization and energy from Richard
- Still considering a relative measurement where we normalize to the πo cross-section rather than try measuring the absolute photon flux.
- Photon flux was largest contributor to error bar in PrimEx in Hall-B
- Hall-D has very long distance between radiator and target and a collimator, making it difficult or impossible to use the tagger for photon flux measurement
- Pair spectrometer is option, but may not be as precise as πo cross-section measurement.
- Further study is required
- We are still missing the azimuthal distribution of the ππ system (not in Elton's plots)
- Reproduced plots shown by Sascha last time of π+ energy with and without secondaries turned on
- Plots were somewhat consistent, but overall much cleaner than what Sashca saw. Most likely due to a newer version of the Hall-D sim-recon code.
- Plot of efficiency vs. z-location of target produced using JLab farm
- Vertex-constraint left on, but the z-location of the constraint was left at z=65cm (i.e. did not match the vertex location) This was an over site
- Will re-reun with vertex-constraint off and also with it on, but adjusted to match vertex location
- Look at πo cross-section as a function of energy for potential use as normalization reaction (Rory)
- Get correlation between polarization and energy from Richard (Rory)
- Update sim-recon version and re-run to confirm Dave's plots (Sascha)
- Re-run z-vertex scan with vertex constraint off as well as on, but aligned with vertex (David)