From PrimExWiki

Present
In person: Pawel Ambrozewicz, Ashot Gasparian, Mark Ito (chair), Liyang Jiang, Xin Qiao Li, Aram Teymurazyan
On phone: Aron Bernstein, Liping Gan, Dan Sober

Agenda

Contents 1 Review of minutes from the last meeting 2 Collaboration Meeting 3 Proposal for more running 4 Final result plan discussion 5 New flux code 6 Announcements 7 Weekly meeting attendance

Review of minutes from the last meeting

No significant comments on last week's minutes.

Collaboration Meeting

It looks like October 13-14 may be too soon for a collaboration meeting to approve a final result. Likely we will try for some time in November. October 13-14 can be used for analysis comparison meetings at JLab.

Proposal for more running

Ashot made a few points:

• We need a list of improvements for justifying more running at a high level. Themes, not details.
• If we propose something for the January PAC we may not run until the spring of 2009.
• We should have final result before going in front of the PAC.

Final result plan discussion

Ashot outlined five items that we need to address before generating a final result for the π⁰ lifetime:

1. The Compton differential cross sections on the level of 2-3%
2. get the same (inside of error bar) fit result (real full scale fit) for the pion decay width for differently extracted pion angle. This also has to be cross-checked by different groups and reach have them reach agreement on the answer.
3. The physical background has to be re-discussed if needed and simulated by all groups whose results are going to be included in the averaging.
4. at least 2 different calculation of the nuclear incoherent have to be implemented by all groups whose results are going to be included in the averaging process.
5. All systematic error sources have to be simulated (MC) and proved by data by all groups included in the avaraging process.

Liping pointed out the the sub-committees review a set of analysis (π⁰, Compton) have not had an opportunity to meet to compare and contrast the related analyses. She suggested that we have one-analysis-topic sub-committee meetings in advance of the collaboration meeting. We agreed to discuss this idea with Eugene.

Other related news:

• Dustin will have a new result in 2-4 weeks (Aron).
• Aron and Rory are working on a proposal on how to combine the separate analyses of a single reaction.

Finally we decided that we should charge the analysis review committee with coming up with a framework for comparing analyses. This would include, but not be limited to, a comprehensive comparision of systematic errors and a accounting of all corrections included in the analyses.

New flux code

Aram has checked in a new version of his flux code. He encourages to the collaboration to use it.

Announcements

• Aram will be giving a PrimEx seminar at the University of Kentucky on October 4.
• Mark will be giving a PrimEx seminar at the University of Connecticut on October 8.

Weekly meeting attendance

We noted that attendance at the weekly meetings has dropped recently. We have sometimes been in a position to discuss important topics but have not had enough of the right people in the room to proceed. This hinders progress. Please try to make an effort to attend the Friday meetings. If the time is inconvenient we can discuss re-scheduling.