[Hallc_running] Draft PRL on the deuteron to proton structure function ratio

[Xiaochao Zheng]

Dear Bill and all:

It's great to see this paper draft and the data are very impressive. I have a couple of general comments for your consideration:

1. first, how are fits (CJ, F1F221, etc) compare with absolute cross sections from the experiment? I think a representative plot for the xsection, perhaps combining all angles (different color) and spectrometers (different marker) would be very useful to show.

2. on page 5, there is a paragraph describing that the results differ from MARATHON by 4.3%, and various normalization differences. Is the paragraph simply meant to point out the differences without making any statement where those normalization shifts may come from or whether they should be applied to data and/or parameterization?

now for the high-x part (which is very exciting!):

3. the part for the extraction of d/u ratio is very short and does not explain how the d/u ratio was extracted. Were the neutron cross section extracted from deuteron minus proton (plus corrections), or was it incorporated in a CJ fit variation and extracted somehow? The ratio of d/u at high x is such an important topic and the method of the extraction must be explained in detail and uncertainties studied.

Also, it appears only CJ was used in extracting d/u. Were there attempts to extract d/u from other framework utilizing the F2 data?  There are also very swift mention of higher twists, TMC and such, but no detail.

4. Along the same idea as comment #3 but worth its own place: Fig.4 is rather weak. One would be way more interested in the absolute value of d/u vs. x, rather than seeing just how much the error bar shrank. An plot as important as d/u at high x should also be accompanied by discussions of the various theoretical predictions of the same quantity.

I hope you find the comments above helpful (and not too silly because I overlooked things).

Thanks,
Xiaochao


________________________________________
From: Hallc_running <hallc_running-bounces at jlab.org> on behalf of William Henry via Hallc_running <hallc_running at jlab.org>
Sent: Monday, June 3, 2024 12:15 PM
To: Hallc_running at jlab.org; hallc at jlab.org
Subject: [Hallc_running] Draft PRL on the deuteron to proton structure  function ratio

Dear Hall C collaborators,

Please find attached our draft paper on the deuteron to proton structure function ratio, which has been prepared for submission to PRL.  These data were taken during the F2 (E12-10-002) and EMC experiment (E12-10-007) run period in 2018 as part of the group of 12 GeV commissioning experiments in Hall C.

Please send your comments on this draft by June 14th.  Even if you have no comments on the paper, please send an email indicating that you agree to be an author.  Also, please pass this draft along to anyone in your group who may not be on the "hallc" or "hallc_running" mailing lists.

Regards,

William Henry for the E12-10-002 experiment