<div><br></div><div>---------- Forwarded message ----------<br>
From: "Simonetta Liuti" <<a href="mailto:sl4y@cms.mail.virginia.edu">sl4y@cms.mail.virginia.edu</a>><br>
To: "O. A. Rondon" <<a href="mailto:or@virginia.edu">or@virginia.edu</a>>, "Simonetta Liuti" <<a href="mailto:sl4y@virginia.edu">sl4y@virginia.edu</a>>, <<a href="mailto:kk7t@virginia.edu">kk7t@virginia.edu</a>>, <<a href="mailto:b1@jlab.org">b1@jlab.org</a>><br>
Cc: "Karl Slifer" <<a href="mailto:karl.slifer@unh.edu">karl.slifer@unh.edu</a>>, "Donal Day" <<a href="mailto:dbd@cms.mail.virginia.edu">dbd@cms.mail.virginia.edu</a>>, "Patricia Solvignon" <<a href="mailto:solvigno@jlab.org">solvigno@jlab.org</a>>, "Narbe Kalantarians" <<a href="mailto:narbe@jlab.org">narbe@jlab.org</a>>, "J.P. Chen" <<a href="mailto:jpchen@jlab.org">jpchen@jlab.org</a>>, <<a href="mailto:ellie@jlab.org">ellie@jlab.org</a>>, "Donald G. Crabb" <<a href="mailto:dgc3q@cms.mail.virginia.edu">dgc3q@cms.mail.virginia.edu</a>>, "Dustin Keller" <<a href="mailto:dustin@jlab.org">dustin@jlab.org</a>><br>
Date: Fri, 15 Mar 2013 09:54:25 -0400<br>
Subject: Re: b1d</div><div><br>
Dear All,<br>
yes, we had a very productive meeting with Oscar, Dustin and Kunal! (I should say that I am in fact also glad I learned about your b_1 proposal from Patricia's talk at INT).<br>
<br>Thanks for the references. Will read.<br>
<br>To summarize, we have agreed that in the next couple of weeks (before the collaboration conference call two Mondays from now), we will perform a study of the observables based on the helicity amplitudes. In a nutshell, we need to check and extend Section 6 of the Hoobhoy, Jaffe, Manohar original paper (that really dates back awhile!).<br>
<br>We already worked out the amps. for our Angular Momentum sum rule paper. Our formalism is sketched out in a short publication<br>
<br><a href="http://prd.aps.org/abstract/PRD/v86/i3/e036008">http://prd.aps.org/abstract/PRD/v86/i3/e036008</a><br>
<br>(we are in the process of writing a longer paper).<br>
We are now going going to extend this and explain what is needed for b_1 (H_5 in the GPD formalism) i.e. define the relevant observables (what type of asymmetries) from the amps.<br>
<br>I have an extra question on whether you would consider detecting an extra photon (and test the AM sum rule ;-) ), but this is a side remark for now.<br>
<br>I am also attaching the talk I gave in Shanghai last Fall.<br>
<br>Please let me know if there in any other question.<br>
<br>Looking forward to working some more on all this!<br>
Simonetta<br>
<br>On Thu, 14 Mar 2013 19:33:06 -0400<br>
"O. A. Rondon" <<a href="mailto:or@virginia.edu">or@virginia.edu</a>> wrote:<br>
>Dear Simonetta and Kunal,<br>
><br>
>It was great to meet with you two and Dustin today, to discuss how to<br>
>measure b1. Here are some items that you should find useful.<br>
><br>
>b1 wiki<br>
><a href="https://hallcweb.jlab.org/wiki/index.php/B1">https://hallcweb.jlab.org/wiki/index.php/B1</a><br>
><br>
>The talk slides I showed at the meeting are under "Relevant Publications"<br>
><br>
>The email attachment from Bob Jaffe replying to our question about sec.<br>
>6 of his paper with Hoodbhoy and Manohar is on my b1 folder on twist<br>
><a href="https://twist.phys.virginia.edu/~or/b1/">https://twist.phys.virginia.edu/~or/b1/</a><br>
><br>
>look for "b1-b2.pdf", but feel free to explore any and all items there.<br>
>Our question, as formulated by Patricia, and Jaffe's reply are at the<br>
>end of this message.<br>
><br>
>There is a b1 mailing list that you can subscribe to, see the wiki. I'm<br>
>copying this message to the mailing list. All interested collaborators<br>
>should subscribe, and future mailings be done preferably using the list.<br>
><br>
>Thank you and looking forward to our collaboration on this project,<br>
><br>
>Oscar<br>
><br>
>> --------------<br>
>> On Nov 30, 2010, at 5:16 PM, Robert L. Jaffe wrote:<br>
>><br>
>>> Dear Patricia,<br>
>>><br>
>>> Attached is a .tex/.pdf file that addresses your question. There<br>
>> certainly is a difference between a state polarized transverse to the<br>
>> beam and one polarized longitudinal to it. I hope the notes are useful.<br>
>>> Bob<br>
>>> <b1-b2.pdf><br>
>>> Robert L. Jaffe<br>
>>> Morningstar Professor of Physics and MacVicar Faculty Fellow<br>
>><br>
>><br>
>>> On Nov 30, 2010, at 12:47 PM, Patricia SOLVIGNON wrote:<br>
>>><br>
>>>> Dear Bob.<br>
>>>><br>
>>>> Because I have been used to think in the case of spin-1/2 and the<br>
>> double-polarization<br>
>>>> measurement, I am still a bit confused about the right measurement<br>
>> method of b1. From<br>
>>>> section 6 of your paper with P. Hoodbhoy and A. Manohar (Nuc. Phys<br>
>> B312, 571(1989)),<br>
>>>> the variable H appears in both sigma_para and sigma_perp.<br>
>>>> My understanding is that H (= the target spin projection along the<br>
>> beam) is equal to +/-1<br>
>>>> in the longitudinal case and to 0 in the transverse case. If that is<br>
>> true:<br>
>>>> sigma_para = sigma_perp = kin_fact *sigma_mott*(F1 - 1/3 b1)<br>
>>>><br>
>>>> and we need either to perform a measurement of F1d from an<br>
>> unpolarized target at the<br>
>>>> same kinematics as for the measurement on the longitudinally<br>
>> polarized target or use a<br>
>>>> model from F1d with the uncertainty that comes along.<br>
>>>><br>
>>>> The submission of the proposal is due tomorrow so I want to make sure<br>
>> I understood the<br>
>>>> formalism for a measurement of b1.<br>
>>>><br>
>>>> Thank you for your help.<br>
>>>><br>
>>>> Best regards,<br>
>>>> Patricia<br>
><br>
><br>
><br>
><br>
><br>
><br>
><br>
><br>
<br>**************************************************************<br>
**************************************************************<br>
Prof. Simonetta Liuti telephone (434) 982-2087<br>
Department of Physics FAX (434) 924-4576<br>
University of Virginia home (434) 973 9593<br>
382 McCormick Rd.<br>
PO Box 400714<br>
Charlottesville, VA 22904-4714<br>
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