STAR HardProbes PWG

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

Hi Yan,

Thanks for your responses to my comments — sorry for the delay in responding to you as I just recovered from an illness. Aside from a few small responses (inline, below), I’m satisfied with the paper moving to the next step, and Nihar has requested GPC formation.

Best,

Isaac

On Jan 9, 2025, at 05:56, wy157543 <star-hp-l AT lists.bnl.gov> wrote:

Hi Nihar and Isaac,

Thank you for your kind comments. The paper and note have been updated and can be accessed at the following links:
https://nam12.safelinks.protection.outlook.com/?url="https%3A%2F%2Fdrupal.star.bnl.gov%2FSTAR%2Fsystem%2Ffiles%2Fpsi2s_paper_pwg_v2.pdf&data=05%7C02%7Cisaac.mooney%40yale.edu%7C622f58ec804c43aff25208dd309c5350%7Cdd8cbebb21394df8b4114e3e87abeb5c%7C0%7C0%7C638720170457158640%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=gou%2BRlH24UZ3eoLSVy6gK3Xv98d4FbIS9u9hl9iiENw%3D&reserved=0
https://nam12.safelinks.protection.outlook.com/?url="https%3A%2F%2Fdrupal.star.bnl.gov%2FSTAR%2Fsystem%2Ffiles%2Fpsi2s_note_pwg_v2.pdf&data=05%7C02%7Cisaac.mooney%40yale.edu%7C622f58ec804c43aff25208dd309c5350%7Cdd8cbebb21394df8b4114e3e87abeb5c%7C0%7C0%7C638720170457187887%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=U7yIwnSbYB7jtYMjUcLtRpKHL2N6sS%2BzcnPxYNcuS8I%3D&reserved=0

Below are the detailed replies.

For paper:

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. ]

I removed the "First" and kept the observation
--------

Line7: "We report on measurements of charmonium …” -> “We report the measurement of charmonium …”

Done.
--------

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.

Done.  The importence for psi2s measurements is described on lines 60-76
--------

L90-92: This sentence sounds redundant and you already mentioned in 
intro. Please drop it.

Done.
--------

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]

BDT cut->BDT threshold,
Added "by requiring the BDT response to be above a threshold." on line133-134 to introduce "BDT threshold".  
--------

_ Many places “200 GeV” is used, use “ \sqrt s_NN = 200 GeV”

Done.
--------

_ 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.

The comparison was added in AN (319-322): The jpsi significence is improved from 133 (traditional method) to 170  (ML method) the ML technique did significantly improve signal salience.
--------

_ 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.

The original content is modified to：
While all three measurements are consistent within uncertainties  at comparable $\langle N_{\rm part} \rangle$ values, the centrality dependence trend observed  in $\sqrt{s_{_{\rm NN}}}$ = 200 GeV Ru+Ru and Zr+Zr collisions seems to more closely resembles 
the measurements at 17.3 GeV than those at 5.02 TeV. 

"at comparable $\langle N_{\rm part} \rangle$" and "trend" were added to make the _expression_ clearer.
--------

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 does convey the more important message. However, if the positions of Fig,3, Fig,4 are exchanged, it is a little strange to discuss ratio instead of double ratio after calculating pp, pA reference. If Fig,4 is placed before calculating pp, pA reference, the discussion of physical results is separated. Another reason is that Fig,3 contains calculations from both models, and therefore they can be introduced together. Personally, I think it would be better to keep the current order. it is not necessary that the money.
--------

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?


Added " The band at unity represents the relative uncertainty in interpolated $\psi$(2S) to J/$\psi$ 
ratio in $p$+$p$ collisions." to the captain. 
Regarding the calculation of "CNM effect" and "QGP Temperature",
we may need to further consult Tsinghua group.
--------

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----------------------------------------------------------
---
For note:

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?


Yes, the slight \eta dependence that still exists after recalibration does result from slight differences between the fit results and the data, but these differences have little effect on the analysis results. Because the recalibration is only convenient for the selection of nsigmaE cut and the calculation of nsigmaE cut efficiency. In addition, the small deviation is taken into account in efficiency correction since the correction is estimated with a data-driven method.

---

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?

Electrons from Dalitz decay are equally good for estimating efficiencies compared to photon conversion. What matters is the
electron purity, not its source. The selection of the pairMass cut takes into account both the statistics and the electron purity.
For example, in 40–80% centrality, photon conversions are also included to increase statistics. (New 20-40% and 40-80% centrality graphs added)

---

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?

Fig. 11 includes more information than the features used in ML. Only the features shown in Fig. 17 have been used for identification, 
all of which have low correlation with pairMass. More detail describes for the features used in ML is added in AN (190-200)

> I notice that cross-checking Fig. 11 with Fig. 17, the tr1(2)NsigmaPi seem to have some correlation with pairMass, and are used. Did you check the effect of removing them? 

---

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?

Thanks for your reminding, I have added some content to better describe these steps. (222-227)

---
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?


We do not see the need to use embedding for background since utilizing data is always better. In fact, we do not have embedding for background since our simulation only embeds psi(2S) signal. Then the question is whether there is any residual difference between data and embedding after the alignment procedure, and if so how would that affect the results. We do not have a clear answer to that since if we know there is a difference we would have corrected it. What we can do is to check the dependence of corrected Jpsi and psi(2S) counts, with raw counts from data and efficiency from machine learning, on the BDT response. A flat distribution is seen in Fig. 19, which shows that embedding agrees with data quite well after alignment. Furthermore, variations in the results from using different BDT cuts are included in the uncertainty, which is another way to gauge the difference between data and embedding

> Although I don’t agree with the heuristic that “utilizing data is always better” for exactly the reason that I mentioned above, I am satisfied with the rest of the response.

---

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

Yes, it's normalized count

---

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?

Yes, this is true for ψ(2S). Because more significant suppression in central collisions for psi(2S) results in worse signal to background ratio. 
(At BDT cut = 0.7, the signal significance is only 1.7σ.)  

---

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

Indeed, the templates obtained by ToyMC cannot be perfectly described by the Crystal Ball function. This is an interesting feature and we will continue to investigate that. However, what we take from the fitting are the ratios of various Crystal-ball parameters between Jpsi and psi(2S), which should still be good even if the templates do not fit ver well. In data analysis, Jpsi peak is fit with all Crystal-ball function parameters being free (the fit works well as seen in Figs. 26 and 27), while psi(2S) peak fit is constrained by Jpsi fit parameters and the parameter ratios from ToyMC.

> Okay, I understand your point that only the ratios of parameters are used, but it would be great if, as you say, you continue to investigate it, and point it out to the GPC.

---

Fig. 28. What is causing the bump ~ 500 MeV? Comparing to e.g. https://nam12.safelinks.protection.outlook.com/?url="https%3A%2F%2Fdrupal.star.bnl.gov%2FSTAR%2Fsystem%2Ffiles%2FJianZhou_hf_20220120_v3.pdf&data=05%7C02%7Cisaac.mooney%40yale.edu%7C622f58ec804c43aff25208dd309c5350%7Cdd8cbebb21394df8b4114e3e87abeb5c%7C0%7C0%7C638720170457203729%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=CIR0Ei0M1qKrGiUx0NMHmeFnEDwLpICdaR5mcPXl75I%3D&reserved=0 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?

In terms of the bump, I always think that comes from interplay of two effects: 
i) efficiency increases with pt as electron's dE/dx increases with pt and thus more likely to generate a TPC hit, and also the track length increases with pt; 
ii) on the other hand, electron's efficiency decreases with pt since at low pt electron tracks can bend through TPC boundaries and still get reconstructed while at high pt electron tracks are straight and they are more likely to be lost in the boundaries.

The major differences between Jian's analysis and this analysis are high luminosity in run16 which could affects TPC performance in terms of the bump. The variation in TPC occupancy from central to peripheral events is much larger for Au+Au than for Isobar, which is why Jian seems a larger centrality
dependence


Best,

Yan and PAs

-----原始邮件-----
发件人: "Mooney, Isaac" <isaac.mooney AT yale.edu>
发送时间:2025-01-05 09:06:27 (星期日)
收件人: "star-hp-l AT lists.bnl.gov" <star-hp-l AT lists.bnl.gov>
主题: Re: [[Star-hp-l] ] Measurement of ψ(2S) production in Ru+Ru and Zr+Zr collisions at 200 GeV is Ready for PWG Review

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://nam12.safelinks.protection.outlook.com/?url="https%3A%2F%2Fdrupal.star.bnl.gov%2FSTAR%2Fsystem%2Ffiles%2FJianZhou_hf_20220120_v3.pdf&data=05%7C02%7Cisaac.mooney%40yale.edu%7C622f58ec804c43aff25208dd309c5350%7Cdd8cbebb21394df8b4114e3e87abeb5c%7C0%7C0%7C638720170457217719%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=BvIZwNWPwJJynlRUXNnHwD8N8YRGOZetELEEeGWUQVY%3D&reserved=0 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://nam12.safelinks.protection.outlook.com/?url="https%3A%2F%2Fdrupal.star.bnl.gov%2FSTAR%2Fblog%2Fwy157543%2FMeasurement-psi2S-production-RuRu-and-ZrZr-collisions-200-GeV-0&data=05%7C02%7Cisaac.mooney%40yale.edu%7C622f58ec804c43aff25208dd309c5350%7Cdd8cbebb21394df8b4114e3e87abeb5c%7C0%7C0%7C638720170457238977%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=E3oUjPPMFNgF1xD6AjsviQpknUNhYRnnZJPAgpEcj%2Bo%3D&reserved=0
Paper
draft:https://nam12.safelinks.protection.outlook.com/?url="https%3A%2F%2Fdrupal.star.bnl.gov%2FSTAR%2Fsystem%2Ffiles%2Fpsi2s_paper_pwg.pdf&data=05%7C02%7Cisaac.mooney%40yale.edu%7C622f58ec804c43aff25208dd309c5350%7Cdd8cbebb21394df8b4114e3e87abeb5c%7C0%7C0%7C638720170457255015%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=nKkUCcNAXXfyn6ue6PxQ8qepnlYqqarwXwrz9aJPsD4%3D&reserved=0
Analysis note:
https://nam12.safelinks.protection.outlook.com/?url="https%3A%2F%2Fdrupal.star.bnl.gov%2FSTAR%2Fsystem%2Ffiles%2Fpsi2s_note_pwg.pdf&data=05%7C02%7Cisaac.mooney%40yale.edu%7C622f58ec804c43aff25208dd309c5350%7Cdd8cbebb21394df8b4114e3e87abeb5c%7C0%7C0%7C638720170457269310%7CUnknown%7CTWFpbGZsb3d8eyJFbXB0eU1hcGkiOnRydWUsIlYiOiIwLjAuMDAwMCIsIlAiOiJXaW4zMiIsIkFOIjoiTWFpbCIsIldUIjoyfQ%3D%3D%7C0%7C%7C%7C&sdata=a%2B%2FJ7q7eL1tILMl4sM3nxtn86nrK8%2FEWa4zlizJPvbg%3D&reserved=0
We would appreciate it if you could review the documents and provide
us with your valuable comments and suggestions!
Best regards,
Yan for PAs