STAR HardProbes PWG

["Mooney, Isaac" <isaac.mooney AT yale.edu>]

Hi Yan and PAs,

Due to my delay in reviewing the materials, I focused on the analysis note as 
the paper draft can be tuned up during the GPC if necessary. Congratulations 
to you on an extremely well-written note. I have a handful of comments below, 
and I find that the analysis is ready to move to GPC formation, pending any 
input from Qian. I may send comments on the paper draft at some point, but 
that doesn’t need to delay the formation request.

Thanks,
Isaac

142. I see that after applying the procedure, there is still a residual eta 
dependence although the phi dependence is nicely removed. Is this caused by 
the imperfect agreement of the fit with the data especially in the negative 
rapidity region? Is this non-zero nsigma_e close enough to zero that it 
produces a minimal effect in the analysis?

175. Just to make sure I understand, this cut on the invariant mass implies 
that only Dalitz decays of pi0s are included in the sample, while photon 
conversion typically falls just outside the requirement, right?

204. This isn't 100% true is it? We see in the Background plot in Fig. 11 
that the track pT or p has a correlation of ~ 0.25 for example. And this 
makes sense given the relation between invariant mass and momentum. Did you 
check whether the results were modified significantly if the observables 
which have some degree of correlation with the pairMass were removed from 
consideration as training features?

Eq. 4. I understand the procedure you're following to change the mean and 
sigma of the embedding nsigma distributions, but the subscripts 1,2,3 were a 
little confusing to me for a second. Could you either explicitly explain them 
in the text (e.g. "the numerical subscripts refer to a value in the embedding 
at the corresponding step in the correction procedure" or similar), or use a 
less opaque notation?

219. Sorry for this possibly silly question, but isn't there a concern that 
if you use embedding for signal and data for background that the model may 
distinguish the two based on some subtle difference not between signal and 
background but between embedding and data (that is left over after the 
feature alignment procedure)? Was the training tried with embedding for 
background as well, and if so was it approximately the same result?

Fig. 15. Just curious, what is the y-axis here? Is it bin-width and 
integral-normalized count? Or something else?

Fig. 20. I can't tell if my eye is fooling me or not, but it looks like the 
relative statistical uncertainties on the 0-80% range are slightly bigger 
than the 40-80% range. Is this true?

Fig. 25. What should we make of the fact that the Crystal Ball fits are quite 
poor?

Fig. 28. What is causing the bump ~ 500 MeV? Comparing to e.g. 
https://drupal.star.bnl.gov/STAR/system/files/JianZhou_hf_20220120_v3.pdf s. 
14 [from run 16], this bump does appear but a) to a seemingly lesser extent 
(for the same set of cuts), and b) with more of a centrality dependence. Do 
you have an insight into the difference?

> On Dec 24, 2024, at 02:04, Nihar Sahoo <nihar AT rcf.rhic.bnl.gov> wrote:
>
> Dear PAs,
>
> I have gone through the AN and paper draft. I find both the materials in 
> good shape, besides my following comments.
> Please take a look at my comments below.
> If Isaac and Qian will sign off with all these comments, then we can 
> request for the GPC formation around 1st week of January.
>
>
> Title: “First observation of charmonium sequential suppression in heavy-ion 
> collisions at  Relativistic Heavy Ion Collider” -> “ Measurement of 
> charmonium sequential suppression in heavy-ion collisions at  Relativistic 
> Heavy Ion Collider”  [ “First …” in title sounds awkward and a reader can 
> judge it. ]
>
> Line7: "We report on measurements of charmonium …” -> “We report the 
> measurement of charmonium …”
>
> L48-51: “…has  been measured in Pb+Pb collisions at …” Better to mention 
> what we observed at the LHC experiments and what more information we can 
> get at RHIC measurement and why it is important to measure at RHIC energy.
>
> L90-92: This sentence sounds redundant and you already mentioned in intro. 
> Please drop it.
>
> L138: “… from data for different BDT cuts, “ it is not clear from the text 
> what are BDT cuts. Please elaborate and avoid words like “cuts”. Use 
> condition or criteria, etc. [Similarly for other places]
>
> _ Many places “200 GeV” is used, use “ \sqrt s_NN = 200 GeV”
>
> _ It would be important to point out that what is advantage of using BDT/ 
> supervised ML technique over traditional invariant Mass combinatorial 
> subtraction method. A account will enhance this paper. Please indicate if 
> such comparisons are discussed in AN.
>
> _ L280-289: “While all three measurements are consistent within 
> uncertainties, the centrality dependence in 200 GeV Ru+Ru and Zr+Zr 
> collisions seem to more closely resemble the measurements at 17.3 GeV…” 
> This is not true within uncertainty . “…seem to more closely resemble….” 
> Please paraphrase .
>
> I think it would be better to make Fig,3 as final money plot for this 
> paper. Whereas Fig.4 and it discussion should come before double ratio vs 
> Npart plot.
> I find Ratio vs pT plot is less significant, due to uncertainty, than 
> current Fig.3 to convey the message.
>
> Fig.3:
> _ Please add in the legend what is that gray band on unity line. It is 
> unclear.
> _ Can we have p/d+Au 200 GeV CNM effect calculation from Tsinghua group? 
> That would even strengthen the claim.
>
> _ Is there any discussion or information on QGP Temperature from Tsinghua's 
> group calculation?
>
> Thank you
> Nihar
>
>
> On 2024-11-02 16:21, wy157543 wrote:
>> Dear HPs,
>> The paper draft and analysis note for “First observation of
>> charmonium sequential suppression in heavy-ion collisions at
>> Relativistic Heavy Ion Collider” are ready for pwg review. The
>> associated documents can be found as follows:
>> Webpage:
>> https://drupal.star.bnl.gov/STAR/blog/wy157543/Measurement-psi2S-production-RuRu-and-ZrZr-collisions-200-GeV-0
>> Paper
>> draft:https://drupal.star.bnl.gov/STAR/system/files/psi2s_paper_pwg.pdf
>> Analysis note:
>> https://drupal.star.bnl.gov/STAR/system/files/psi2s_note_pwg.pdf
>> We would appreciate it if you could review the documents and provide
>> us with your valuable comments and suggestions!
>> Best regards,
>> Yan for PAs