STAR HardProbes PWG

[Gabe Dale-Gau <gdaleg2 AT uic.edu>]

Dear Ronrong,

I checked the paper I am citing for Raa, and confirmed that you are correct: Raa is built with fully corrected spectra. 

So, I reversed the order of my own corrections. I now apply Raa correction before smearing. I have updated the preliminary slides in the same location as before:

https://drupal.star.bnl.gov/STAR/blog/gdalegau/Preliminary-Figures-Request-Hard-Probes-2024-Baryon-Meson-Ratios-Jets

I have added another slide (first slide in backup) comparing these two methods, Raa before smearing and Raa after smearing, to demonstrate that the difference between these two techniques is small, and fits well within our reported systematics. The resulting fake rate has been updated everywhere in the slide deck, including results, as I am now using Raa before smearing as my nominal measurement. 

The difference in measured fake rate is as follows:

R = 0.2: 13% --> No change

R = 0.3: 37% --> 39%

R = 0.4: 60% --> 63%

Thank you again for your attention to detail on this technique. Let me know if you have any further questions on the matter.

Best,

Gabe

On Tue, Sep 10, 2024 at 9:17 PM Ma, Rongrong <marr AT bnl.gov> wrote:

Hello Olga

Gabe should clarify, but my understanding is that Raa is indeed built with fully corrected jet spectra in pp and AA collisions, i.e. detector effects and background fluctuations are corrected for via unfolding. That is why I think Raa weighting should be applied to pp spectrum before smearing. If Raa is on reco level, then I agree that smearing with AA background fluctuations double-counts the effect. 

Thanks. 

Best

Rongrong

On Sep 10, 2024, at 9:41 PM, Evdokimov, Olga <evdolga AT uic.edu> wrote:

Dear Rongrong,

Thank you for your feedback and the discussion. We need to make sure we are not double-counting the effects: in ideal world we would have both pp and AA jet spectra unfolded and then constructed the Raa, but my understanding it is not what is done, and the Raa is of reco level. This corresponds to weighting the measured  pp spectra with Raa to get reco AA jet spectra, which is what Gabe has done originally. Your request to smear the pp spectra for AA bg fluctuations is a reasonable study, but double counts the smearing as Raa already has it. In any case, Gabe has both estimates in , but I am hesitant to put all the differences (even if subdominal to other effects) into the systematics , because of the double counting. What do you think ?

Best regards,

Olga

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From: star-hp-l-request AT lists.bnl.gov <star-hp-l-request AT lists.bnl.gov> on behalf of Ma, Rongrong <marr AT bnl.gov>
Sent: Tuesday, September 10, 2024 7:43:29 PM
To: star-hp-l AT lists.bnl.gov <star-hp-l AT lists.bnl.gov>
Subject: Re: [[Star-hp-l] ] Preliminary requests

 

CAUTION: External Sender

Hello Gabe

Thanks for preparing the new slide to address my comments, which looks good. I think the reason one seems larger deviation at low pt is that jet pt spectrum gets steeper at lower pt. 

It seems like you apply jet R_AA to p+p spectrum after smearing. Ideally, one should apply it to corrected spectrum in p+p. Since that is not available, it is probably more correct to apply it to p+p spectrum before smearing. 

Best

Rongrong

On Sep 10, 2024, at 5:58 PM, Gabe Dale-Gau <gdaleg2 AT uic.edu> wrote:

Hi Isaac,

Here is a link to my preliminary figures request post: https://drupal.star.bnl.gov/STAR/blog/gdalegau/Preliminary-Figures-Request-Hard-Probes-2024-Baryon-Meson-Ratios-Jets

I have currently addressed all comments from the HP-pwg meetings as well as the analysis meeting this morning. I have included one new slide in response to Rongrong's comments today. It is the first slide in backup, showing a comparison of the p+p jet spectra before and after embedding. This slide demonstrates the effect of introducing Au+Au background into p+p jets. The resulting post-embedding jet spectra, with the addition of R_AA, is used in my template fits to determine fake rate. These spectra now account for the presence of Au+Au and the published R_AA.

I am happy to field any further questions and comments via email. I will upload my presentation draft for the conference soon.

Thanks,

Gabe

On Tue, Sep 10, 2024 at 2:10 PM Mooney, Isaac <isaac.mooney AT yale.edu> wrote:

Hi Hard Probes presenters,

I would appreciate it if you could reply to this message with a link to your preliminary request slides (if applicable) and a sentence or two describing any follow-ups you are currently implementing from previous meeting discussions before preliminary status can be given, as well as an estimate for the time/date when you will send a final set of request slides. Sorry to those of you who have already sent slides in some form to other email chains — it would just be helpful for the conveners if we could collect the latest and most up-to-date links all in one place as we review.

Thanks,
Isaac

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