STAR HardProbes PWG

[Yi Yang <yiyang0429 AT gmail.com>]

Hi Ziyue,

Sorry for the delayed reply. I have some minor comments/suggestions on paper draft and analysis note for your consideration. 

  

Paper draft: 

 - General: you missed all references, please add them in the new version. 

 - General: it seems you have many places that are incomplete, it would be good to have the "final" version for us to comment on. 

 I. Introduction: 

   - heavy ion collisions --> heavy-ion collisions (many places) 

   - it feels that the "Cold Nuclear Matter Effect" came out of the blue. Probably need to think about how to introduce it... 

   - 200GeV --> 200 GeV

   - published similar -measurement --> published measurement 

II. Experiment: 

   - Probably having a short introduction of STAR in the beginning will be better. 

   - Question: could you please remind me why don't you use TOF to improve PID? Since 2012 results used TOF, you probably need to explain why you don't need TOF in 2015. 

III. Data analysis:   

   - The first paragraph reads a bit strange. I don't understand why you mention "The invariant yield in p+p and p+Au collisions is extracted from the data by the same procedure." in the beginning. Actually also the next sentence... 

   - You don't need to put "nHitFit > 20" (and nHitsDedx > 10) in the paper since they are only for STAR internal.

   - I would think you don't need Eq.(3)

   - Please define what "RC" is first. 

   - I would think there are too many details in the embedding section, so you can consider reducing them. But you can also keep them if you want. 

   - I also think the systematic part for smearing a' is too detailed. I am not sure if it is important to the reader outside STAR. 

   - Please finish the part of trigger bias and vertex finding. 

   - Please complete Table II. 

   - I would suggest adding a figure for all uncertainties vs pT. 

IV. Results: 

   - pT ! 0.5 GeV/c --> pT > 0.5 GeV/c

V. Summary 

   - add 200 GeV

   - The conclusion reads a bit plain, probably you need to think how to make it look more important. 

Analysis note: 

  - General: it is a very clear and complete note, I only have some minor comments. 

  - p16: Ranking ! 0 --> Ranking > 0 

  - Figure 11: the caption is messed up. Could you please remind me why "BBCAnd" efficiency for MC is higher than J/psi? 

  - Please add the final results (cross sections, RAA with mu+mu results, predictions) in the analysis note. 

Cheers,

Yi

On Thu, Aug 8, 2024 at 3:08 AM Mooney, Isaac <isaac.mooney AT yale.edu> wrote:

Hi Ziyue,

Sorry for my delay. I have some comments below on your analysis note and paper draft. I found the analysis note to be quite thorough, and only had a single comment on it. The paper draft was a bit less polished, but many of my comments were related to grammar/spelling, which can also be addressed by the English QA person in the GPC. In general, I find it ready to move to the GPC formation assuming at least the physics-related comments are addressed.

Thanks, and congratulations on getting the analysis to this stage,

Isaac

PAPER DRAFT:

General typographic comments:

-- please be careful about articles throughout. E.g. "by quantum chromodynamics", "in an early stage of"/"in the earliest stage", "making mini Big Bangs", "at Brookhaven National...", "of a heavy quark-antiquark...", "Quarkonium is a..."

-- please spell check after each draft is done. There are a lot of typos that a spell checker would catch (some of which I list below).

-- please add line numbers in future drafts.

-- please upright most sub/superscripts and all differentials (e.g. "T" in "p_{T}" and "d" in "d^{2}N"). 

pg. 2

"believed to have existed"

"after the Big Bang"

"Big Bangs: ultra-"

"Heavy-Ion Collider"

"Large Hadron Collider"

"Recherche Nucléaire"

"orders of magnitude"

"cleaner probes of the QGP"; cleaner than what?

"binding potential"

pg. 3

"Several measurements"

"the modification of the yield"

"when the transverse"

"regions have very different levels"

It's a bit weird to say "the modification...is flat around unity" since a ratio being flat around unity means there is actually no modification. So either "the ratio of the yield relative..." or "there is no modification of the yield relative to p+p when the transverse..."

"different levels of modification compared to those at midrapidity."

"Different" [I will stop mentioning typos now to save time. Please refer to my general typographic comment above.]

It's not clear what the framework of CGC effective theory is "alternative" to.

"which also has explanatory"

Please add citations for many of the statements on this page. 

Don't forget that you have this "[more?]" here twice, either to be removed or replaced by more description of the physics.

"measurement of" [and throughout]

"a constraint" or "constraints"

pg. 4

"are measured"

"They are quantified"

"Both measurements...have"

Make sure to cite the other STAR measurements.

"from published results...in years"

"data used...were collected using the high-..." [I will stop mentioning bad syntax now to save time, and leave it for the English QA in the GPC.]

pg. 5

Don't forget to add the BBC lower eta coverage. I think it's 3.4, but could be misremembering.

pg. 6

I don't understand why the dE/dx of the electron has a double expectation. What does this mean in this context?

Did you mean to write both 4.2 and 4.3? Or is one a typo?

pg. 7

RC is jargon and needs to be defined.

pg. 8

Although I understand what you're doing, it still took me a few read-throughs of the sentences starting from "The additional smearing is implemented..." to get what you were trying to say here (especially with "by varying a into different a'"). Please take another look and try to rephrase to make it more clear.

pg. 10

Don't forget to fill the values into the table. 

What do you mean "suppressed by the former 2"? Do you mean "dominated by..."?

pg. 11

I think you mean ""-" indicates lack of estimation in the original publication"

Could you walk through the steps you used to get the combined result for one of these uncertainties? E.g. the BEMC eff.: I'm wondering why the lower bound of the combined uncertainty is 0.8 although the lower bounds on the individual measurements are 0, 0.3, and 0 respectively. Is it just because of a discrepancy between the central values in the datasets?

As a corollary, I'm not sure why you would obtain a systematic uncertainty decrease from an individual to combined result when only one value is given, when you say "the specific item of uncertainty is assigned so that it will not impact the combined result of this item.", as in the TOF efficiency -- i.e. why did it decrease so much when the only applicable value is from 2012?

Maybe I'm not understanding the meanings in the table -- could you be precise by what you mean by uncertainty here, in the legend? By "4 < pT < 10 GeV/c" do you mean that the lower bound in the table is the lowest uncertainty of any of the bins within that larger range, and similar for the upper bound? [It's also confusing because for BHT2 Eff you have a range of "1.1 - 1.0", so either that's a typo or maybe it's from the first bin in the range to the last?]. And I'm assuming this is relative uncertainty, in which case could you also add a % somewhere in the table, or specify it in the legend?

How do you handle the fact that the Emb. Mod. uncertainty is included in the statistical uncertainty, in terms of combining uncertainties?

It's not actually true that the "combination universally improved the precision", right? E.g. the BEMC Eff. (BHT2 Eff.) gets bigger for the combined result than for 2015 (2012). And conceptually, should we expect the combination to improve anything but the statistical precision? For example, in the case of perfectly correlated uncertainties, like the BEMF Eff. is assumed to be, the combined absolute systematic uncertainty should only increase, right? Hence why you say that they are "conservatively" assumed to have correlation coefficients equal to 1.

pg. 12

There is some uncertainty on the branching fraction (i.e. 5.97% \pm 0.03%) -- is this taken into account?

"hidden from" -> "not shown in"

pg. 13

Not sure if you meant the upside down exclamation mark to be a ">" or "<"?

It might be good to comment on the slight tension between the muon and electron channel measurements, unless you've looked into it and the disagreement in terms of sigmas is < some small n and my eye is exaggerating the effect.

pg. 14 

Is there no value for the 2015 data in the 12 - 14 GeV/c bin?

pg. 15

To me it makes a bit more sense to include Fig. 2b and Fig 3 into a Fig 3a and 3b since the only thing that is changing is the fit, whereas the current Fig 2a and b are more conceptually different. It might even be possible to make that potential Fig 3a and 3b into a single figure with two ratio panels in the plot, one with the ratio to the mixed fit and one with the ratio to the dielectron channel fit, if you just additionally draw the dielectron combined fit line on the uppermost panel as well, and add one legend entry for it.

It's a little confusing to say "The latter is responsible for the J/psi enhancement above 2.5 GeV/c" since the J/psi is not enhanced above 2.5 GeV/c in these results. I assume you mean in the model. So it would be good to specify "The latter is responsible for the model's J/psi enhancement."

It seems contradictory to say ~'models and data are all consistent', followed immediately by ~'this model underpredicts data by a few sigma'. We typically say things are consistent when the 1sigma bands overlap. So in this case we wouldn't say "all" models are consistent. Maybe: "All model calculations are consistent with data within theoretical and experimental uncertainties except the comover model which underpredicts data above 3.5 GeV/c by 2.3sigma."

pg. 16

Missing "= 200 GeV"

This last sentence ends the paper on a sour note, since "[un]satisfactory" has a negative connotation. A better way to end would consider what could be done in the future to improve models/experiment so that the agreement improves. E.g. perhaps there could be some improvement to (n)PDFs in the future, or further tuning to CGC+ICEM and Lansberg could be done using this new J/psi measurement. This also gives some motivation for the reader for why they should care other than improved precision only.

ANALYSIS NOTE:

pg. 8: Should this second bin in ZDC rate for p+Au not be discarded since it's such a large fluctuation with fairly few counts (apparently, from the statistical uncertainty)? It's a very large weight to be applied, compared to all the other data.

On Jul 24, 2024, at 23:57, Ziyue Zhang <zzhan70 AT uic.edu> wrote:

Hello conveners,

This is a friendly reminder for this request. I know this version draft is far from final, but we'd like to hear from you guys and I would implement everything in the next version.

Best,

Ziyue

On Fri, Jun 28, 2024 at 2:11 PM Ziyue Zhang <zzhan70 AT uic.edu> wrote:

Dear convener,

I would like to request for the review of the paper Nuclear Modification Factor on the Inclusive J/ψ Production in p+Au collisions at  √(sNN) = 200 GeV with the STAR Experiment from the PWG.

The webpage can be found here, where the latest version of the analysis note, paper draft as well as the PWGC Preview meeting slides, comment (notes) and response can all be found.

The formation of the GPC is also requested after the PWG review concludes.

Best,

Ziyue