STAR Flow, Chirality and Vorticity PWG

[subhash <subhash AT rcf.rhic.bnl.gov>]

Dear Chunjian, PAs,

Thanks for sending these materials to the list and sorry for the delay 
in response. I have gone through the documents. The AN note is very 
comprehensive. The paper draft is in a good shape. I am fine with moving 
towards to the next steps. I sign off with a few suggestions, mostly on 
the presentation/texts, which could be considered during the GPC 
deliberations.


General comments:
If the Au+Au data stand as a baseline (mild deformation), how does it 
compare with hydro model predictions, especially Fig. 3 shows model 
calculations for U+U only. How does these models describe the Au+Au 
data. Such discussions could be elaborated in the text.

The deformation parameter is extracted based on the hydro models in 
central collisions. The models do not do a good job in describing the 
trends in mid-central and peripheral collisions. A few sentences would 
be helpful in discussing why they failed.

In Fig. 1, you could go to ultra-central collisions (0-0.5%). While for 
extraction of beta_2 on Fig. 4, you use 0-5% as ultra-central. Is it 
driven by limitation of statistics in model?

How do you select centrality in the models, based on impact parameter 
or, multiplicity distribution?

In the summary section, it would be good to sharpen what are the 
implications of these observations in a broader context. One can argue 
more precise deformation parameter can be obtained in low energy data. 
How does our HIC data helps?

Minor comments:
title: It seems very generic. A few details like RHIC or collision 
systems could be included.
quadrupole deformation --> nuclear deformation

abstract:
transversal momentum --> transverse momentum
For reporting the beta_2 values here (and in summary), did you add the 
stat and syst errors in quadrature, or a simple sum? I suggest removing 
"Syst+Stat" and quote value +/- error;
data model comparison --> comparison with state-of-the-art hydrodynamic 
model;
at a 10^-24 scale --> what is the relevance of time scale here?

l#13: what do you mean by unusual nuclear structure?
l#103: ultra-central (0-0.5%)
l#109: STAR GEANT4 --> I guess it is GEANT3. In stead you could rephrase 
to STAR detector simulation in GEANT3 framework.
l#110: You could remove the technical term "which is embedded into real 
data". Or, add a few lines how embedding is done.
l#115: you could probably rephrase, "inverse distribution of tracks"
l#118-126: There could be two sources for systematic, one for v2 and one 
for rho_n. It is not clear which part you are discussing here.
recalculating v_n --> Not clear how do you recalculate, with varying 
eta-gap?
When you vary the analysis cuts (e.g. X1, X2), not clear how it is 
varied between the extremes X1 and X2.
l# 151: lead to
l#198: standard, two- and three-sub event methods
l#253: "Since the literature .... robust" --> please rephrase
l#258-262: data models comparison --> You could probably specify the 
beta_2 is derived from IPG+Music.
The uncertainty on beta_2 seems mostly dominated by the statics from 
model calculation, right?  Moreover, there could be possible systematics 
in model that is not reported here. It could be mentioned.
l#262: You could add references to low energy literature.
l#237 & 277:  IPG+Music means IPG+Music+UrQMD?
Fig 2: upper row --> panel  a and b; upper row --> panel c and d
Fig. 4: for the STAR data in left panel, is it possible to draw it as a 
marker with a band.
You could mention the shaded bands for IPG model, I guess it correspond 
to statistical error.

Thanks and regards,
Subhash


On 2022-10-21 01:15 AM, Chunjian Zhang via Star-fcv-l wrote:
> Dear Convenors,
>
> Thank you for reviewing our analysis. If there are no further
> comments/suggestions, we would like to request GPC.
>
> If possible, we also would like to recommend Shusu Shi as GPC chair
> and Maowu Nie as code QA for the management to consider.
>
> The information is listed below:
>
> Title: Observational constraints on the quadrupole deformation in
> relativistic nuclear collisions
>
> PAs: Shengli Huang, Jiangyong Jia, Roy Lacey, Niseem Magdy, Chunjian
> Zhang
>
> Target Journal: Physical Review Letters
>
> Paper draft:
> https://drupal.star.bnl.gov/STAR/system/files/Observational%20constraints%20on%20quadrupole%20deformation%20in%20relativistic%20nuclear%20collisions.pdf
> Analysis note:
> https://drupal.star.bnl.gov/STAR/system/files/Observational%20constraints%20on%20quadrupole%20deformation%20with%20relativistic%20nuclear%20collisions_0.pdf
> Webpage:
> https://drupal.star.bnl.gov/STAR/blog/chunjian/probing-quadrupole-deformation-uranium-relativistic-nuclear-collisions
>
> Replies to PWGC comments:
> https://drupal.star.bnl.gov/STAR/system/files/Note_for_PWGC_meeting.pdf
> Analysis code: /star/u/chunjian/storage/workdir
>
> Thank you,
> Chunjian for the PAs
>
> On Fri, Sep 30, 2022 at 10:18 AM Chunjian Zhang
> <chun-jian.zhang AT stonybrook.edu> wrote:
>
> > Dear Convenors and all,
> >
> > We have worked out the paper draft for the analysis of
> > "Observational constraints on the quadrupole deformation in
> > relativistic nuclear collisions."
> >
> > Please find the manuscript attached at
> https://drupal.star.bnl.gov/STAR/system/files/Observational%20constraints%20on%20quadrupole%20deformation%20in%20relativistic%20nuclear%20collisions.pdf
> > The analysis note is also attached at
> https://drupal.star.bnl.gov/STAR/system/files/Observational%20constraints%20on%20quadrupole%20deformation%20with%20relativistic%20nuclear%20collisions_0.pdf
> > A reply for the PWGC meeting is also attached at
> https://drupal.star.bnl.gov/STAR/system/files/Note_for_PWGC_meeting.pdf
> > For more information on the presentations, please refer to
> https://drupal.star.bnl.gov/STAR/blog/chunjian/probing-quadrupole-deformation-uranium-relativistic-nuclear-collisions
> > Your comments and suggestions are welcome and appreciated.
> >
> > Best regards
> > Chunjian
> _______________________________________________
> Star-fcv-l mailing list
> Star-fcv-l AT lists.bnl.gov
> https://lists.bnl.gov/mailman/listinfo/star-fcv-l