STAR HardProbes PWG

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

Hi Nihar,

Thanks a lot for addressing my comments. I just have one major response to your replies (see below).

-Isaac

On Jul 31, 2023, at 4:34 AM, Nihar Sahoo <nihar AT rcf.rhic.bnl.gov> wrote:

Hello Isaac,

Thank you for your comments.
I have implemented most of them in v1.

My replies can be found below.

Physics/structure/message
36. This is slightly misleading, since the jet mass itself is not presented. Rather the >CollinearDropped mass is shown (and >the groomed mass fraction is discussed as well). This is probably >too detailed to go into at this point in the proceedings, so >maybe "jet mass, and jet shape" could >just be changed to "observables relating to the distribution of momentum and >energy within the jet" or >similar. Although then I would almost suggest just removing "like energy-energy...jet shape".

I modified the sentence. DM/M and mu are observables related to jet mass, whereas girth and rho(r) are jet shape observables.

80. It should be mentioned somewhere that the CD measurement uses MultiFold since this is a novel and >exciting technique.

I added one sentence. L93 in current version

92. This is a bit vague, and I'm not sure it will come across what DeltaM/M actually is. Instead of >"the jet mass fraction >resulting from the CollinearDrop", I would recommend something like "the >fraction of the jet mass that would be groomed >away by SoftDrop"

I rephrased it a bit differently. Please have a look at it.

96. "indicates narrower splits lead to smaller virtuality transfer"

I find it complicated.  I keep as it is.

> I don’t understand what is complicated about this phrasing. It’s actually something more directly tied to the actual data. I believe pretty strongly that this is a better phrasing than the original which I think can lead to confusion. We had a discussion over email about this with Raghav who suggested the new phrase to avoid this confusion (July 3 was their response if you want to read it) and it is how it was referred to subsequently in Monika’s proceedings.

102. "whereas PYTHIA-8 may need further tuning of parameters related to the hard process and jet >evolution"

I rephrased.

124. Is this true? What about >https://nam12.safelinks.protection.outlook.com/?url="https%3A%2F%2Furldefense.com%2Fv3%2F__https%3A%2F%2Finspirehep.net%2Fliterature%2F1817734__%3B!!P4SdNyxKAPE!C1ucvZ-&data=05%7C01%7Cisaac.mooney%40yale.edu%7C0e79ad31931f401b7b1808db91a0f8e4%7Cdd8cbebb21394df8b4114e3e87abeb5c%7C0%7C0%7C638263893678931494%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=dHdAuLSNUOBJdfHvLfuYZcE6LAhtfQIy8FCvL%2B42TDo%3D&reserved=0>aaitRDJD7FN_jphkNYEZ1A2Al0Ko79fMBiQH2CSg-3LalJgqpIeq0gCyjOULO39xTavwu6zW6znO6xDD5ureW$  ? >Maybe you >meant to say "at RHIC"? Also, I think there should at least be some comment about the physics of this >result >even if it's as quick as "which could potentially be explained by medium response".

Please note that, for the first time, both STAR and ALICE reported together the observation of jet acoplanarity at QM2022. I agree to add "at RHIC". In the same sentence, it was mentioned "…due to jet-medium interaction in heavy-ion collisions."
This is what we can say from experiment at this point on physics message. Mechanisms are for theorists.

> I disagree with this, but if you feel uncomfortable making any claims, I won’t push it.

136. Again, I think it would be good to have a half-sentence explanation of the result, even if we >point to the reference for >the full story. You do this on l. 143 very nicely. Something like >"suggesting that at least for high-p_T constituents, QGP >coalescence does not contribute to the >hadronization process in a jet."

I think we need a detailed study on this baryon-to-meson ratio in jet that Gabe is working on. And we should not draw any conclusion on these preliminary results. Let's wait for final results.

160. I don't understand why only the suppression in Au+Au collisions is highlighted as strong. I would >also call the isobar suppression strong at high multiplicity.

Yes, you can call it but not stronger than Au+Au. Please see Fig.8 left. And compare blue and red markers.

> Agreed, I would not call it stronger than Au+Au, I just didn’t understand the focus on one over the other since they are both strong levels of suppression.

170. It would be interesting to add a reference to a paper which calculates the dissociation >temperature of Upsilon so an >inference can be made about the minimum peak temperature of the QGP at >RHIC.

I have added STAR PRL paper reference. Other relevant information can be found in this paper.

196. I'm not sure what this sentence is intended to mean. …

I rephrased that sentence.


Cheers
Nihar

On 2023-07-30 01:01, Mooney, Isaac wrote:

Hi Nihar,
Your proceedings lay out STAR’s hard probes program very well. I have
some comments below, but the majority are just spelling and grammar
related, so I grouped them together.
Thanks,
Isaac
Spelling/grammar/other small things
10. "aims to investigate"
12. "Amassing a..."
14. "hard probes"
16. "QGP" or "the QGP's"
20. "is compared"
24. "antiquarks"
29. "processes"
30. "to explore the" -> "exploration of the"; "regimes"
32. Remove "constant"
33. "serve as a"
34. "experiment's"
35. "conference in Aschaffenburg..."
37. "phenomena
38. "studied" -> "done"/"accomplished"/...; "direct photon + jet, and
hadron+jet" -> "jets recoiling from hadrons or direct photons"
40, 41. "are also discussed", "are thoroughly discussed" is repetitive.
42. "for the hard"
44. "experiment"; "comprises several..."
45. "A recent"
47. "for triggering, and for"
50. "Plane"; Problem with singular/plural clash here. Suggest: "The
Event-Plane Detector (EPD) is composed of two symmetric halves placed
at both..."
54. "subsystems"
56. "enabling detection of neutral..."
57. Remove "high p_T" since it's at forward eta; funny spacing between
"<" and "4".
64. Another singular/plural clash here => "correlator (or EEC) helps..."
66. "allows one to measure" or "allows for measurement of"; "in QCD".
69. "using the anti-k_T algorithm in p+p collisions"
72. "angular"
74. Remove "with a"
76. "in the quark-gluon regime"; "\times" is unnecessary
79. "observable"
81. What you said is true, but it omits its use just to remove NP
contribution from the jet shower/hadronization.
85. "of the parton shower" or "of parton showers"
88 (and throughout): "in Ref. [7]"
89. Move "the" after "pQCD and"
95. "as defined and shown in"
102. "observables"
111. This sentence seems a bit garbled. E.g. "R=0.2 over 0.5 (...)
coincidence" is not coherent. Maybe: "...reports the comparison
(R^0.2/0.5) of yields of jets with two different radii (0.2, 0.5)
recoiling from direct..."
116. "contributes to our understanding of"
119. Remove "On the other hand"
126. This is worded a bit misleadingly. It makes it seem like you're
saying the baryon/meson ratio in heavy-ion collisions is > 1, which is
not what is meant. Suggest: "The enhancement of the baryon-to-meson
yield ratio in heavy-ion collisions compared to pp collisions..."
133. "preference for pion production over proton production"; "on the
left of Fig..."
135. "200 GeV, for jets with a hard-core selection and radius of 0.3,
the (p+\bar{p})..."
146. "jets show"
147. "consistent with that from"
149. "A semi-inclusive measurement of recoil jets in coincidence with
a charged hadron within trigger p_T of...is also presented"
151. "systems" (also 153.)
Fig. 7. "as a function of p_T,jet"
153. Remove "In STAR,"
160. "However"
161. "Besides" -> "In addition"
162. "along with its"; "no significant"
165. "states"; "thermalization"
166. "and sizes"
169. "significantly more"
References: Can you hyperlink the DOIs and arXiv numbers?
Physics/structure/message
36. This is slightly misleading, since the jet mass itself is not
presented. Rather the CollinearDropped mass is shown (and the groomed
mass fraction is discussed as well). This is probably too detailed to
go into at this point in the proceedings, so maybe "jet mass, and jet
shape" could just be changed to "observables relating to the
distribution of momentum and energy within the jet" or similar.
Although then I would almost suggest just removing "like
energy-energy...jet shape".
80. It should be mentioned somewhere that the CD measurement uses
MultiFold since this is a novel and exciting technique.
92. This is a bit vague, and I'm not sure it will come across what
DeltaM/M actually is. Instead of "the jet mass fraction resulting from
the CollinearDrop", I would recommend something like "the fraction of
the jet mass that would be groomed away by SoftDrop"
96. "indicates narrower splits lead to smaller virtuality transfer"
102. "whereas PYTHIA-8 may need further tuning of parameters related
to the hard process and jet evolution"
124. Is this true? What about
https://nam12.safelinks.protection.outlook.com/?url="https%3A%2F%2Furldefense.com%2Fv3%2F__https%3A%2F%2Finspirehep.net%2Fliterature%2F1817734__%3B!!P4SdNyxKAPE!C1ucvZ-aaitRDJD7FN_jphkNYEZ1A2Al0Ko79fMBiQH2CSg-3LalJgqpIeq0gCyjOULO39xTavwu6zW6znO6xDD5ureW%24&data=05%7C01%7Cisaac.mooney%40yale.edu%7C0e79ad31931f401b7b1808db91a0f8e4%7Cdd8cbebb21394df8b4114e3e87abeb5c%7C0%7C0%7C638263893679087272%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=WpY36Xn8FoOxuNIHrznCDEexwz89FDSvZzelMND95Ys%3D&reserved=0
? Maybe you meant to say "at RHIC"? Also, I think there should at
least be some comment about the physics of this result even if it's as
quick as "which could potentially be explained by medium response".
136. Again, I think it would be good to have a half-sentence
explanation of the result, even if we point to the reference for the
full story. You do this on l. 143 very nicely. Something like
"suggesting that at least for high-p_T constituents, QGP coalescence
does not contribute to the hadronization process in a jet."
160. I don't understand why only the suppression in Au+Au collisions
is highlighted as strong. I would also call the isobar suppression
strong at high multiplicity.
170. It would be interesting to add a reference to a paper which
calculates the dissociation temperature of Upsilon so an inference can
be made about the minimum peak temperature of the QGP at RHIC.
196. I'm not sure what this sentence is intended to mean. Do you mean
that the results cast doubt on our ability to discern the effect of
the initial medium configuration on hard probes? Because I don't see
how you get that from the results. We have a positive jet v2 which
seems to suggest the opposite. And the J/psi v2 is almost
centrality-inclusive and has large uncertainties, and even so there
may be a hint of a v2 for the TPC EP method. And your sentence is a
very broad statement not just about STAR data but about "heavy-ion
collisions" in general, which also seems contradicted by other results
from the field, e.g.
https://nam12.safelinks.protection.outlook.com/?url="https%3A%2F%2Furldefense.com%2Fv3%2F__https%3A%2F%2Farxiv.org%2Fpdf%2F2307.14097.pdf__%3B!!P4SdNyxKAPE!C1ucvZ-aaitRDJD7FN_jphkNYEZ1A2Al0Ko79fMBiQH2CSg-3LalJgqpIeq0gCyjOULO39xTavwu6zW6znO6xD3ZHcVi%24&data=05%7C01%7Cisaac.mooney%40yale.edu%7C0e79ad31931f401b7b1808db91a0f8e4%7Cdd8cbebb21394df8b4114e3e87abeb5c%7C0%7C0%7C638263893679087272%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=omJlYh8n0AzsltlAyc5ZqRFyoW0py2FGuYLmNvGZeDQ%3D&reserved=0
. I also don't understand how we can reconcile that the RAA in isobar
and AA is only dependent on Npart -- which is related to energy
density -- with your statement that there are questions about
sensitivity to the initial energy density. This seems to be exactly
what these results are sensitive to.
But maybe I am misunderstanding what "raises questions" meant, in
which case some different language could be used. Maybe you meant
instead that it leads to future possibilities to explore the role of
geometry in heavy-ion collisions.

On Jul 26, 2023, at 2:23 AM, Nihar Sahoo via Star-hp-l <star-hp-l AT lists.bnl.gov> wrote:
Hello All,
Sorry for this late submission of my proceedings on HP2023 STAR highlights.
I requested HP2023 organizers to consider my late submission by email and they agreed to consider it.
So it would be Ok from their side.
As you know, Joern Putschke kindly presented for me at HP2023. However, he suggested me to put only my name for the STAR collaboration in these proceedings. If there is any STAR rule in this direction, please let us know.
Please have a look at my HP2023 proceedings on STAR highlights.
Thank you
Nihar
On 2023-07-26 11:38, webmaster--- via Star-hp-l wrote:

Dear Star-hp-l AT lists.bnl.gov members,
Nihar Sahoo (nihar AT rcf.rhic.bnl.gov) has submitted a material for a review,
please have a look:
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