[Shms_users] New proposal: Recoil polarization in 4He, 2H, and 1H(e, e'p)

[Stephen A. Wood]

Steffen:

    Could someone give a presentation about this proposal at the Hall C 
users meeting in January.  While the meeting will be just after the PAC, 
I think it will be good for Hall C users to hear about it, independent 
of the PAC result.

    Thanks, Steve

Garth Huber wrote:
> Dear Collaborators,
>
> We are preparing a new proposal to measure the proton recoil polarization in 
> 4He(e,e'p)3H and 2H(e,e'p)n in Hall C. This is an update of our earlier proposal 
> PR08-001 and would continue the series of our experiments at MAMI and JLab Hall 
> A (E93-049 and E03-104). Key features of the new experiment are:
>
> (1) One new high-precision data point for the 4He polarization-transfer double 
> ratio at Q2 = 1.8 GeV2.  Models, constrained to our E03-104 data, using free 
> nucleon form factors agree above 1.3 GeV2 while the predicted effect of medium 
> modified form factors are as large as 5%.  This data point should put tight 
> constraints to possible medium effects.
>
> (2) A significantly improved missing momentum coverage at Q2 = 1.0 GeV2. Here, 
> we propose to measure a range almost covering -200 to +300 MeV/c in parallel 
> kinematics.  Medium effects are expected to grow with the virtuality of the 
> knocked out proton (as do other reaction mechanism effects to which these 
> additional data can provide crucial constraints). We will focus on the x > 1 
> region to minimize FSI effects.  This missing momentum distribution will give us 
> an additional high-precision data point at Q2 = 1.0 GeV2.
>
> (3)  We propose to study the momentum distribution in both, the 4He(e,e'p)3H and 
> 2H(e,e'p)n reactions to compare knockout data of tightly and weakly bound 
> protons.  These data can help answering the question whether medium effects 
> depend on the mean nuclear density or rather on the momentum or virtuality of 
> the nucleon.
>
> A draft version of the proposal is posted at:
>
> http://www.jlab.org/~strauch/pac37/he4_pac37.pdf
>
> We would like to invite you to join this proposal.  Please let us know.  We 
> would appreciate any comments or suggestions you may have regarding this draft. 
> If you send your remarks, please, refer to the date on the front page as we keep 
> updating the text.  The text is not final, yet.
>
> Sincerely,
>
> Steffen Strauch,
> also for Ed Brash, Garth Huber, and Ron Ransome.
>
>   

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