Difference between revisions of "Pi0 Polarizability Meeting Aug 30, 2019"
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# [[Media:LOI12-19-003 TAC THY.pdf | TAC Physics Comments]] | # [[Media:LOI12-19-003 TAC THY.pdf | TAC Physics Comments]] | ||
## One-pion exchange contribution (C-parity conservation?) | ## One-pion exchange contribution (C-parity conservation?) | ||
+ | ##* Jose: there is a chiral g -> pi+pi-pi0, but not g -> pi0 pi0 pi0. | ||
## Eliminating contributions from iso-scalar resonances (experiment) | ## Eliminating contributions from iso-scalar resonances (experiment) | ||
## Sensitivity of cross sections to polarizability (theory) | ## Sensitivity of cross sections to polarizability (theory) | ||
## Corrections due to photon virtuality (theory) | ## Corrections due to photon virtuality (theory) | ||
+ | ##* Jose: There are two issues 1) virtuality of exchanged photon 2) re-scattering effects in the target. | ||
# [[Media:EltonMark emailto SteveDytman.png | email from Elton and Mark to PAC Reviewer Steve Dytman]]. Homework to prepare for a proposal (Questions not answered by the LOI): | # [[Media:EltonMark emailto SteveDytman.png | email from Elton and Mark to PAC Reviewer Steve Dytman]]. Homework to prepare for a proposal (Questions not answered by the LOI): | ||
## So far we have only qualitatively investigated backgrounds, but do not find any particular reactions that have not been considered for pi0 and pi+pi- Primakoff reactions. Detailed studies needed. | ## So far we have only qualitatively investigated backgrounds, but do not find any particular reactions that have not been considered for pi0 and pi+pi- Primakoff reactions. Detailed studies needed. | ||
+ | ##* Ilya: Primakoff eta data taken this spring might be useful to check backgrounds. Calibration is at the 1% level. No pi0 seen in the CompCal. | ||
## Determine how backgrounds will affect the determination of the pi0pi0 Primakoff cross section. | ## Determine how backgrounds will affect the determination of the pi0pi0 Primakoff cross section. | ||
## Evaluate sensitivity to run time. Need to justify requested beam time. | ## Evaluate sensitivity to run time. Need to justify requested beam time. | ||
+ | ##* Ilya: We should consider both running time and which targets to use. Different targets will have different sensitivities to background. Having multiple targets will allow studies of systematics. Primakoff-eta was originally proposed on H and He, but now consideration is given to using Carbon instead of H. But possible contamination of data with transitions to excited states of Carbon were a concern. | ||
+ | ##* Beni: Need to minimize the amount of vacuum near the target to eliminate sources that don't come from the target since we do not measure the vertex. | ||
+ | ##* Mark: Note that once the experiment is decoupled from CPP, one may wish to optimize not only targets, but also beam energy or other parameters. | ||
+ | ##* Ilya: It is useful to have as much commonality with CPP as possible for reasons of comparison. For example pi+pi- rescattering to pi0pi0 makes these reactions interconnected. | ||
## Develop the case for measuring pi0pi0 production at threshold aside from the determination of the polarizability. | ## Develop the case for measuring pi0pi0 production at threshold aside from the determination of the polarizability. | ||
+ | ##* Elton: It would be useful to develop a physics case for a precision measurement at threshold in addition to its sensitivity to polarizability. | ||
# [https://www.jlab.org/exp_prog/PACpage PAC47 Report] | # [https://www.jlab.org/exp_prog/PACpage PAC47 Report] | ||
# Other business | # Other business | ||
# Next meeting | # Next meeting | ||
+ | #* We will continue meeting at 10 am on Friday and we will meet bi-weekly. Next meeting is Sep 13. |
Latest revision as of 12:06, 30 August 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
- Contact Dai regarding the pi0pi0 proposal (Elton).
Tentative Agenda
- Announcements
- Wiki pages moved to open repository
- Action Items
- Lingyun Dai, Hunan University: Changsha, Hunan, CN (dailingyun@hnu.edu.cn)
- PAC 47
- TAC Physics Comments
- One-pion exchange contribution (C-parity conservation?)
- Eliminating contributions from iso-scalar resonances (experiment)
- Sensitivity of cross sections to polarizability (theory)
- Corrections due to photon virtuality (theory)
- email from Elton and Mark to PAC Reviewer Steve Dytman. Homework to prepare for a proposal (Questions not answered by the LOI):
- So far we have only qualitatively investigated backgrounds, but do not find any particular reactions that have not been considered for pi0 and pi+pi- Primakoff reactions. Detailed studies needed.
- Determine how backgrounds will affect the determination of the pi0pi0 Primakoff cross section.
- Evaluate sensitivity to run time. Need to justify requested beam time.
- Develop the case for measuring pi0pi0 production at threshold aside from the determination of the polarizability.
- PAC47 Report
- TAC Physics Comments
- Other business
- Next meeting
Minutes
Attending: David, Elton, Jose, Ilya, Beni, Mark (JLab); Rory (UConn); Svetlana, Aleks (MU)
- Announcements
- Wiki pages moved to open repository
- Action Items
- Lingyun Dai, Hunan University: Changsha, Hunan, CN (dailingyun@hnu.edu.cn)
- PAC 47
- TAC Physics Comments
- One-pion exchange contribution (C-parity conservation?)
- Jose: there is a chiral g -> pi+pi-pi0, but not g -> pi0 pi0 pi0.
- Eliminating contributions from iso-scalar resonances (experiment)
- Sensitivity of cross sections to polarizability (theory)
- Corrections due to photon virtuality (theory)
- Jose: There are two issues 1) virtuality of exchanged photon 2) re-scattering effects in the target.
- One-pion exchange contribution (C-parity conservation?)
- email from Elton and Mark to PAC Reviewer Steve Dytman. Homework to prepare for a proposal (Questions not answered by the LOI):
- So far we have only qualitatively investigated backgrounds, but do not find any particular reactions that have not been considered for pi0 and pi+pi- Primakoff reactions. Detailed studies needed.
- Ilya: Primakoff eta data taken this spring might be useful to check backgrounds. Calibration is at the 1% level. No pi0 seen in the CompCal.
- Determine how backgrounds will affect the determination of the pi0pi0 Primakoff cross section.
- Evaluate sensitivity to run time. Need to justify requested beam time.
- Ilya: We should consider both running time and which targets to use. Different targets will have different sensitivities to background. Having multiple targets will allow studies of systematics. Primakoff-eta was originally proposed on H and He, but now consideration is given to using Carbon instead of H. But possible contamination of data with transitions to excited states of Carbon were a concern.
- Beni: Need to minimize the amount of vacuum near the target to eliminate sources that don't come from the target since we do not measure the vertex.
- Mark: Note that once the experiment is decoupled from CPP, one may wish to optimize not only targets, but also beam energy or other parameters.
- Ilya: It is useful to have as much commonality with CPP as possible for reasons of comparison. For example pi+pi- rescattering to pi0pi0 makes these reactions interconnected.
- Develop the case for measuring pi0pi0 production at threshold aside from the determination of the polarizability.
- Elton: It would be useful to develop a physics case for a precision measurement at threshold in addition to its sensitivity to polarizability.
- So far we have only qualitatively investigated backgrounds, but do not find any particular reactions that have not been considered for pi0 and pi+pi- Primakoff reactions. Detailed studies needed.
- PAC47 Report
- Other business
- Next meeting
- We will continue meeting at 10 am on Friday and we will meet bi-weekly. Next meeting is Sep 13.