[Rgc] Jeopardy

[Sebastian Kuhn]

Dear members of the RG-C,

I hope you were able to tune in to my presentation today at the CLAS collaboration meeting. My slides are at https://indico.jlab.org/event/863/ (Thursday morning). Please send your comments, and - MOST IMPORTANTLY - your updated slides.

About the latter: Those of you who attended today’s meeting, you heard the comments from Patrizia and Volker, which echoed what I have been saying: we do NOT need any additional justification why the Physics is great - we need strong arguments why we need 50% more data! The same theme also comes through in the comments from our reader, which are attached. I tried to do this for the case of inclusive DIS - if any of you can provide the same for their favorite channels, please prepare ONE SLIDE (with overlays) to send to me.  For instance, I would love to replace the “p in D” plot with a prediction what we can learn about nDVCS from the already  existing COMPLETE data set, and how our extraction of CFFs (see Silvia’s slide 8 from the RG-B Jeopardy presentation or another relevant observable) would improve if we could shrink the statistical error bars by about 30% (which is the most we can realistically expect for 40 more PAC days).

I propose that we use the entire RG-C meeting next week (last one before the PAC) to discuss improvements to my presentation, also in light of Kumericki’s comments. I will respond to him before the PAC.

Greetings - Sebastian


Begin forwarded message:

From: Krešimir Kumerički <kkumer at phy.hr>
Subject: Comments on J12-24-RunGroupC
Date: June 27, 2024 at 6:44:20 AM EDT
To: "Kuhn, Sebastian E." <skuhn at odu.edu>
Cc: "Dr. Markus Diehl" <markus.diehl at desy.de>, "Ilieva, Yordanka" <ILIEVA at sc.edu>

EXTERNAL to ODU: This email is not from an ODU account. Do not click links or open attachments unless you recognize the sender and know the content is safe.

Dear Sebastian,

I am a member of the PAC52 assigned to do a first reading
of Run Group C Jeopardy update,
(for which you are the contact person),


Since this run group comprises some well-established
and thoroughly reviewed experiments I don't have  many
scientific questions.

Still, PAC has to address some points during Jeopardy review,
and it would be helpful if you had some comments on the following:

1. Jeopardy instructions say that "If the experiment has already received a
portion of its allocated beam time, the spokespersons should present the status
of the analysis of the existing data and the projected results for the final
complete data set. The goal is to show the physics impact of the beam time
requested in the jeopardy update."

I notice that update document focuses on the preliminary results from the
already recorded data (actually small part of it), and I don't see any
projections for the complete data set. This would be singularly
helpful to have, but I certainly understand that this
means a lot of work and likely cannot be produced for the PAC meeting. In that
case, PAC will work with what we have.

2. Is there any change in the status of the collaboration in terms of
institutes, committed staff, and prospective students that could
impact the feasibility of performing and analyzing proposed measurements?


3. Finally, I do have one "scientific" question. TAC report says that
your APOLLO target "has been operating with great success". On the
other hand, you mention problems with pre-irradiation of this target
and consequently the sub-optimal polarization in the first part of
your run, so the remaining 1/3 of the originally requested 120 PAC
days, if approved, would result in more than 1/3 of the additional
statistics. Could this improvement (or previous degradation) be somehow
roughly quantified in terms of some effective PAC days or related quantifier?

Also, when you write in the third-to-last sentence of the report
"... mostly due to (deuterated) ammonia samples ..." do you mean that
measurements with ND3 were more affected by the pre-irradiation problem
than those with NH3, or is the problem ND3-NH3 symmetric? Because if it
is not symmetric wouldn't it make sense to favor ND3 for the remaining data taking?
(Related to this, I am confused by your Beam Requirements List which looks like you
are asking for 40 days (960 hours) for each of the 5 targets.)


Thank you for any comments you can provide.

Best regards,
Kresimir

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