Difference between revisions of "Pi0 Polarizability Meeting Nov 15, 2019"
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#* In the low-energy (unpolarized) limit, the polarizabilities are alpha ~ (A+12 m_pi B), beta ~ -A. The interpretation of C is still needed. | #* In the low-energy (unpolarized) limit, the polarizabilities are alpha ~ (A+12 m_pi B), beta ~ -A. The interpretation of C is still needed. | ||
#* Jose will continue developing his calculations toward a cross section for polarized photons on a heavy target. | #* Jose will continue developing his calculations toward a cross section for polarized photons on a heavy target. | ||
| + | #* Svetlana and Aleks will do a ChipT calculation to one loop with Coulomb photon. | ||
# [https://halldweb.jlab.org/doc-private/DocDB/ShowDocument?docid=4265 Rates on Be] (Elton) | # [https://halldweb.jlab.org/doc-private/DocDB/ShowDocument?docid=4265 Rates on Be] (Elton) | ||
#* Assume 5% target for both Pb and Be. [Note: Ilya checked that the Be target in Gluex is 0.7" (1.78 cm) thick and 1" (2.54 cm) in diameter] | #* Assume 5% target for both Pb and Be. [Note: Ilya checked that the Be target in Gluex is 0.7" (1.78 cm) thick and 1" (2.54 cm) in diameter] | ||
Revision as of 15:53, 15 November 2019
Contents
Meeting Information
Meeting Time And Location
10:00 am ET (JLab time)
CC F228
Connecting
Dummy for now: You can connect using BlueJeans Video conferencing (ID: 949 429 419). (Click "Expand" to the right for details -->):
- Make sure you have created a BlueJeans account via your JLab CUE account using this link:
- http://jlab.bluejeans.com (You should only need to do this once)
- Meeting ID: 949 429 419
- (you may need to type this in, depending how you connect)
- If connecting via Web Browser: click this link (no passcode is needed):
- If connecting via iOS or Android App:
- Use your JLab e-mail address to log in and then enter the meeting ID given above to join the meeting
- If connecting via Phone: Dial one of the following numbers and then enter the meeting ID above and hit "#" or "##"
- Dial: (408) 740-7256 (US or Canada only)
- or, List of International Numbers
- If connecting via Polycom unit:
- Dial 199.48.152.152 or bjn.vc
- Enter meeting ID above
Action Items
- Event generator. Equation for g A -> g pi0 pi0
- Primakoff signal rate for He/Be targets (Elton)
- Contact theorists:
- Lingyun Dai, Hunan University: Changsha, Hunan, CN (dailingyun@hnu.edu.cn)
- Serguei Gevorkyan
- Barbara Pasquini (Rory)
Tentative Agenda
- Announcements
- Action Items
- Rory contacted Barbara. She is very busy at the moment, but promised to take a look at our LOI and let us know how she might be able to support our effort.
- Theory update
- Notes Jose Nov 15
- Jose walked us through the updated version of his notes.
- Jose has written the cross section in the lab frame and in the forward limit.
- For two real photons in gg->pi0pi0, there are 2 hadronic tensors, corresponding to two form factors (A and B).
- For one real and one Coulomb photon gg_C->pi0pi0, there are 3 hadronic tensors, corresponding to three form factors (A, B and C). Previous calculations have ignored the virtuality of the Coulomb photon.
- In the low-energy (unpolarized) limit, the polarizabilities are alpha ~ (A+12 m_pi B), beta ~ -A. The interpretation of C is still needed.
- Jose will continue developing his calculations toward a cross section for polarized photons on a heavy target.
- Svetlana and Aleks will do a ChipT calculation to one loop with Coulomb photon.
- Rates on Be (Elton)
- Assume 5% target for both Pb and Be. [Note: Ilya checked that the Be target in Gluex is 0.7" (1.78 cm) thick and 1" (2.54 cm) in diameter]
- Calculations with some parameterizations for Pb and Be, the expected signal rates on Be are about 90% of those expected on a Pb target.
- Other business
- Next meeting
Minutes
Attending:
