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Hi, Oscar,<br>
<br>
We have done this for the transversity experiment where <br>
our main goal is single target spin asymmetry (beam unpolarized)<br>
and our secondary goal is to get double spin asymmetry as well.<br>
So the beam polarization was high (typically 80%).<br>
We do have beam helicity information in the data such that we can <br>
have the buckets count exactly equal between two beam helicity
states.<br>
Due to the parity beam feed back system, we got the charge asymmetry<br>
between the two states to be at 10-5 level (<50 ppm), much better<br>
than we need. (Without the feedback system, we can typically only
control <br>
the charge asymmetry to ~1x10^-3.) For transversity, the systematics<br>
due to false asymmetry from beam not totally unpolarized is
completely negligible.<br>
<br>
For our low current running with polarized proton/deutron target, we
will need to <br>
rely on feedback system to be run from the other hall. As in g2p
case, we rely on <br>
QWeak feedback, which provided charge asymmetry in Hall A at the
10^-4<br>
level.<br>
<br>
Karl and I can get our g2p students to provide some plots.<br>
<br>
Cheers.<br>
<br>
Jian-ping<br>
<br>
<br>
<div class="moz-cite-prefix">On 5/14/2013 5:58 PM, O. A. Rondon
wrote:<br>
</div>
<blockquote cite="mid:5192B3A0.3060707@virginia.edu" type="cite"><br>
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