[PRad] [EXTERNAL] Re: Presentation for the CLAS Collaboration Meeting

[Patrick Achenbach]

Dear Jingyi

I still believe that the plot is not very attractive. First, it is based on a very old data set from the 1990s. Then, it is not very intuitive to me why the reduced cross section normalized to the squared dipole form factor should not be within a few percent from unity, at least at low epsilon. At epsilon = 0, the reduced cross section equals G_M^2 and the value on the y-axis equals (G_M/G_D)^2, right? I believe one can easily produce a much more convincing plot from today's existing world data set. The A1 data set, Bernauer et al., has Rosenbluth separations for 77 different Q2 values.

I was referring to your label saying "Tagger" on p. 17, it gives the impression that it is used in the measurement.

Have a nice weekend,
Patrick

________________________________________
From: Jingyi Zhou <jingyi.zhou at duke.edu>
Sent: Friday, July 7, 2023 15:17
To: Patrick Achenbach; prad at jlab.org
Subject: Re: [PRad] [EXTERNAL] Re: Presentation for the CLAS Collaboration      Meeting

Hi Patrick,

Thanks for your questions.

The plot on page 4 is from Fig.3 of this paper, I added the reference to the slides now.
https://arxiv.org/pdf/hep-ph/0612014.pdf<https://urldefense.proofpoint.com/v2/url?u=https-3A__arxiv.org_pdf_hep-2Dph_0612014.pdf&d=DwMFAg&c=CJqEzB1piLOyyvZjb8YUQw&r=DexAQjBL_LBq3J1v5tq-2pUGL-q3U3lNFJACyX2xBKA&m=E_EYfRyweu3oKMK978wA9Tm_nYzjkM99u1ajkLgDfSn9CB9wOD1QEel7xDggrg2h&s=ejkZvtT8yGHmd3_8R2wNTNjWrDqn3Ic574InVqdmILw&e=>
It is an example demonstrating the Rosenbluth separation technique. Data points are shown for the Q2 values of 2.5 (open triangles), 5.0 (open circles) and 7.0 (filled triangles) (GeV/c)^2 . The straight lines are linear fits to the corresponding data points.

I am confused about your question on p.17. I don't have any references on p.17.

I also changed that to "proposal" on p.23.

Best,
Jingyi
________________________________
From: Patrick Achenbach <patricka at jlab.org>
Sent: Friday, July 7, 2023 2:40 PM
To: prad at jlab.org <prad at jlab.org>; Jingyi Zhou <jingyi.zhou at duke.edu>
Subject: Re: [PRad] [EXTERNAL] Re: Presentation for the CLAS Collaboration Meeting

Dear Jingyi,

thanks for the nice slides. I have a few comments:

I don't fully understand your plot on page 4.
- Which data set is plotted there? Is this from PRad? No reference is given.
- Why are the values between 7 and 9? Is this in per mille? The differences of any cross section data form the standard dipole form are maximum of 2-3 %.
- What is the Q2-value for the three different data sets?

I also don't quite understand the references to the tagger on p. 17. The tagger is not operational. I have not seen a request to upgrade the tagger in the DRad proposal.

On p. 23 I would call the DRad a "proposal", in line of what Ashot was discussing.

Best,
Patrick

________________________________________
From: PRad <prad-bounces at jlab.org> on behalf of Jingyi Zhou via PRad <prad at jlab.org>
Sent: Friday, July 7, 2023 14:06
To: prad at jlab.org
Subject: [PRad] [EXTERNAL] Re: Presentation for the CLAS Collaboration  Meeting

Dear all,

Thank you very much for your comments! Attached please find the latest version of my presentation.

Best,
Jingyi
________________________________
From: PRad <prad-bounces at jlab.org> on behalf of Jingyi Zhou via PRad <prad at jlab.org>
Sent: Wednesday, July 5, 2023 6:42 PM
To: prad at jlab.org <prad at jlab.org>
Subject: [PRad] [EXTERNAL] Presentation for the CLAS Collaboration Meeting

Dear all,

Attached are my slides for the CLAS Collaboration Meeting. The talk will be on next Friday (July 14th) at 10:05 am. It will be 20mins presentation + 5mins Q&A. Please let me know if you have any suggestions.

Thanks,
Jingyi