[Clas12_dileptons] Pass 2 Improvements

Rafayel Paremuzyan rafopar at jlab.org
Wed Jul 5 13:22:27 EDT 2023

Hi Pierre,

are these 52 runs are all "Good" runs that you use in the analysis, or you have runs that are not it the "Good runs" list?
I am wondering why few runs don't show big improvements, e.g. 1st two runs, or the last run (on your last slide).

Also the improvement of the width seems to me to be real to me, as in your third slide
the bottom bar of ratio plots shows a bump at the mass of J/psi, otherwise I would just expect the ratio to increase uniformly
over all the mass range.

From: Clas12_dileptons <clas12_dileptons-bounces at jlab.org> on behalf of Pierre Chatagnon via Clas12_dileptons <clas12_dileptons at jlab.org>
Sent: Wednesday, July 5, 2023 12:21 PM
To: Richard Tyson (PGR) <r.tyson.1 at research.gla.ac.uk>; Clas12_dileptons at jlab.org <clas12_dileptons at jlab.org>
Subject: Re: [Clas12_dileptons] Pass 2 Improvements

Hello all,

Similarly to what Richard shown, I ran my code on the currently available pass2 data for RGA (52 runs of Spring 2019 out of 121). Some of the figures I have produced are in the slides attached that I am planning to sent to Timothy to include in his presentation at the collaboration next week.

There is a great improvement in the number of Jpsi, close to 86% (a very similar number to what Richard mentioned). The width seems better too (though it needs full statistics to really give a good conclusion on this point).

Please let me know if you have any questions/comments. Otherwise I plan to send these plots to Timothy by tomorrow



From: Richard Tyson (PGR) via Clas12_dileptons<mailto:clas12_dileptons at jlab.org>
Sent: Monday, July 3, 2023 8:37 AM
To: Clas12_dileptons at jlab.org<mailto:clas12_dileptons at jlab.org>
Subject: [Clas12_dileptons] [EXTERNAL] Pass 2 Improvements

Hi All,

As you may know pass 2 has been completed for the RG-B spring2019 dataset. Unfortunately, we had some power outages due to flooding in our offices in Glasgow so I was only able to transfer over roughly 60% of spring 2019. On these 60% of spring2019 we see an improvement of:

  *   ~80% for J/psi produced on the proton ( ep_bound -> (e') e+ e- p ).
  *   ~50% for J/psi produced on the neutron ( en_bound -> (e') e+ e- n ).

I've attached some slides related showing the pass1/pass2 comparison. I'm going on holidays tomorrow so I won't be able to attend the next couple of meetings but please let me know by email if you have any questions. I think Silvia is intending to give an update at the collaboration meeting about pass 2 improvements in RG-B and I was also going to send her these slides.


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