Difference between revisions of "Pi0 Polarizability Meeting Feb 28, 2020"
From GlueXWiki
(→Minutes) |
(→Minutes) |
||
(5 intermediate revisions by the same user not shown) | |||
Line 67: | Line 67: | ||
# Announcements | # Announcements | ||
+ | #* Elton sent an e-mail to Justin to request an extension for our proposal till next Friday. [Note added: Justin replied saying that he felt this schedule would be ok.] | ||
# Action Items | # Action Items | ||
# Theory update | # Theory update | ||
Line 72: | Line 73: | ||
#* Jose modified the text and Mark included it into the draft early this week. It includes some clarifications and new references | #* Jose modified the text and Mark included it into the draft early this week. It includes some clarifications and new references | ||
#* Details of Jose's calculation will be added into an Appendix. | #* Details of Jose's calculation will be added into an Appendix. | ||
− | # Experiment | + | # Experiment updates |
− | # | + | # [https://userweb.jlab.org/~ilarin/npp/coul_ff_2pi0.pdf Coulomb FF] (Ilya) |
#* Computed the Coulomb FF by modifying the parallel momentum for the increased mass and the cross section scaled for two pions (x2) | #* Computed the Coulomb FF by modifying the parallel momentum for the increased mass and the cross section scaled for two pions (x2) | ||
#* Rory: How does this differ from the standard electron scattering FF? It is a Glauber calculation that includes absorption corrections for the pion. | #* Rory: How does this differ from the standard electron scattering FF? It is a Glauber calculation that includes absorption corrections for the pion. | ||
#* The calculation shows enhanced secondary maximum relative to single pi0. The higher momentum transfer requires increased precision in the calculation, which has required more computer time. | #* The calculation shows enhanced secondary maximum relative to single pi0. The higher momentum transfer requires increased precision in the calculation, which has required more computer time. | ||
#* Ilya is now working on obtaining the photon flux for the Primex-eta experiment, so that the data can be properly normalized. | #* Ilya is now working on obtaining the photon flux for the Primex-eta experiment, so that the data can be properly normalized. | ||
− | # | + | # [https://halldweb.jlab.org/doc-private/DocDB/ShowDocument?docid=4364 Update] (Elton) |
+ | #* Elton has used an approximation for the 208Pb FF * sinthe^2 to simulate the nuclear coherent background. | ||
+ | #* The Primakoff peaks at about 0.2 deg (compared to 0.02 deg for single pi0 production). This is due to the increased mass of the final state. | ||
+ | #* The nuclear coherent distribution peaks at about 0.7 deg. | ||
+ | #* The coherent sum of Primakoff and nuclear coherent result in a distribution wider than pure Primakoff but do not exhibit two distinct peaks. | ||
+ | #* Fitting to the distribution can be used to extract the signal, under the assumption that the shapes are known. | ||
+ | #* There was some discussion about examining the distributions coming from lighter nuclei, e.g. 12C. | ||
# Work list for the draft proposal to collaboration | # Work list for the draft proposal to collaboration | ||
#* Clarification to questions from the PAC where possible | #* Clarification to questions from the PAC where possible | ||
Line 87: | Line 94: | ||
#** This item will not be attempted for the proposal draft. | #** This item will not be attempted for the proposal draft. | ||
#* Analysis of PRIMEX data (Ilya) | #* Analysis of PRIMEX data (Ilya) | ||
− | #* Assessment of nuclear coherent background (Elton) | + | #* Assessment of nuclear coherent background (Elton, Rory) |
#** What is the t-dependence of the sigma (500)? | #** What is the t-dependence of the sigma (500)? | ||
+ | # Schedule for draft | ||
+ | #* Updated sections should be added to the draft by next Wed. That will give us 2 days to polish before submitting our draft to the collaboration. | ||
# Other business | # Other business | ||
# Next meeting | # Next meeting | ||
+ | #* Next meeting will be next Friday, March 6, 10 am. |
Latest revision as of 15:51, 28 February 2020
Contents
Meeting Information
Meeting Time And Location
10:00 am ET (JLab time)
CC F228
Connecting
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
- ChiPT calculation to one loop with Coulomb photon (Svetlana and Aleks)
Tentative Agenda
- Announcements
- Action Items
- Theory update
- Experiment update
- Update (Elton)
- Work list for the draft proposal to collaboration
- Clarification to questions from the PAC where possible
- Update to theory section (Jose and Mark)
- Sensitivity of cross section to polarizabilities
- Jose: The sensitivity is determined by extrapolating into the kinematic region for polarizabilities and will take effort. For now, we will use the estimates from Dai/Pennington.
- Initial optimization of experiment (e.g. target position)
- This item will not be attempted for the proposal draft.
- Analysis of PRIMEX data (Ilya)
- Assessment of nuclear coherent background (Elton)
- What is the t-dependence of the sigma (500)?
- Other business
- Next meeting
Minutes
Attending: Elton, Beni, Ilya, Alexander, Jose, Mark, Rory
- Announcements
- Elton sent an e-mail to Justin to request an extension for our proposal till next Friday. [Note added: Justin replied saying that he felt this schedule would be ok.]
- Action Items
- Theory update
- Updates to proposal
- Jose modified the text and Mark included it into the draft early this week. It includes some clarifications and new references
- Details of Jose's calculation will be added into an Appendix.
- Experiment updates
- Coulomb FF (Ilya)
- Computed the Coulomb FF by modifying the parallel momentum for the increased mass and the cross section scaled for two pions (x2)
- Rory: How does this differ from the standard electron scattering FF? It is a Glauber calculation that includes absorption corrections for the pion.
- The calculation shows enhanced secondary maximum relative to single pi0. The higher momentum transfer requires increased precision in the calculation, which has required more computer time.
- Ilya is now working on obtaining the photon flux for the Primex-eta experiment, so that the data can be properly normalized.
- Update (Elton)
- Elton has used an approximation for the 208Pb FF * sinthe^2 to simulate the nuclear coherent background.
- The Primakoff peaks at about 0.2 deg (compared to 0.02 deg for single pi0 production). This is due to the increased mass of the final state.
- The nuclear coherent distribution peaks at about 0.7 deg.
- The coherent sum of Primakoff and nuclear coherent result in a distribution wider than pure Primakoff but do not exhibit two distinct peaks.
- Fitting to the distribution can be used to extract the signal, under the assumption that the shapes are known.
- There was some discussion about examining the distributions coming from lighter nuclei, e.g. 12C.
- Work list for the draft proposal to collaboration
- Clarification to questions from the PAC where possible
- Update to theory section (Jose and Mark)
- Sensitivity of cross section to polarizabilities
- Jose: The sensitivity is determined by extrapolating into the kinematic region for polarizabilities and will take effort. For now, we will use the estimates from Dai/Pennington.
- Initial optimization of experiment (e.g. target position)
- This item will not be attempted for the proposal draft.
- Analysis of PRIMEX data (Ilya)
- Assessment of nuclear coherent background (Elton, Rory)
- What is the t-dependence of the sigma (500)?
- Schedule for draft
- Updated sections should be added to the draft by next Wed. That will give us 2 days to polish before submitting our draft to the collaboration.
- Other business
- Next meeting
- Next meeting will be next Friday, March 6, 10 am.