[Pwg] Ae+e- SoLID proposal submitted

[Xiaochao Zheng]

Dear all positron and EW physics and SoLID supporters:

Thank you all for your support. The new proposal on Ae+e- measurement was submitted to PAC49 this morning.  You may view the submitted version at PR2021_c3q_submitted.pdf<https://drive.google.com/file/d/1uTViWvFCx4lNY0Ar-SnePUABvjNc--im/view?usp=sharing>.

Changes made since version 3 (last Friday) are:
1) added short description of using the ARC magnet for online monitoring of beam energy (2nd paragraph in section 3.4) (thanks to Paul Gueye).  In fact, with the online monitoring/drift corrections pushing 1E-5 on the beam energy, I wonder if we can in fact develop a method to constrain/measure the Ebeam difference between e+ and e- runs to better than the 5E-4 level currently used in the proposal.

2) added a section on Coulomb correction (now section 4.6). (thanks to Jianping and Paul Gueye).

3) corrected (back) calculation of HT effects using H3nu (it is defined as x*F3nu = x*F3nu(LT) + H3nu/Q2, different from Eq.(1) of Ref.[41]). Given that I had only one hour to recalculate, I was able to only update the numbers but did not add detailed discussions to the proposal. I hope to produce some plots to illustrate whether the new data can be used to constrain HT effects on F3's (directly on F3gammaZ and connected to F3nu).  Simultaneously constraining HT, C3q, among many experimental systematic effects, will likely be more involved than the method presented in the proposal, suggestions on this topic will be welcome.

4) added texts from JAM group on QED higher order corrections (new paragraph at the end of section 4.7 and some words to TPE study, section 5.3). (thanks to Wally)

5) all author signups received as of 7am EDT this morning were included in the proposal, and all but one were included through the PAC submission platform (I could not find one author's email address as required by the online system). Signups received after 7am EDT today will be included in future submissions (sorry, the online submission system had a hard deadline that I did not want to miss.)

6) minor grammatical edits throughout (thanks to many who sent me comments over the weekend).

A few more "business" items:

1) If you are receiving this email but have not subscribed to any of the pwg at jlab.org, halla_coll at jlab.org, and solid at jlab.org mailing lists, please consider subscribing to one of them.  I hope to send future communications on TAC, theory, and PAC comments on the proposal to these 3 mailing lists.

2) I will give a short presentation on this proposal at the upcoming SoLID collaboration meeting, on Friday June 11th.  The proposal will also be reviewed for SoLID and Hall A collaboration status during that week/meeting.

3) If anyone is interested in measuring the same observable on the proton with SoLID or at the EIC, please let's discuss.

Now the real work has begun.

Best regards,

Xiaochao
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