STAR HardProbes PWG

[Nihar Sahoo <nihar AT rcf.rhic.bnl.gov>]

Hello Dandan,

Please find my comments on the paper draft and AN.

Comments on Paper draft:

1. Need to discuss centrality definition in the paper (a small para)
2. Line11: Need to introduce what is “J/psi Polarisation” in the 
introduction ?
3. Para 40-57:  I try to understand the discussion about the 
regeneration effect on J/psi polarisation at RHIC energy. We know at 
RHIC regeneration effect is relatively smaller compared to LHC. Then 
what is the importance of this comparison at RHIC in even isobar 
collisions for this measurement. Is not this a deviation of main physics 
of J/Psi production mechanism ? Or Am I missing something here?
4. Why there is no THU model calculation for Lambda_inv in FIg.4,5?
5. How do we decide 25% of J/psi regeneration fraction from Fig.6? I can 
see polarisation zero in data then how do we set red vertical line at 
25%?
6. “Systematic uncertainties “ section, please quote the percentage of 
systematic uncertainties  of each source in their subsection.
7.  Line215: “…4–10 GeV/c or eight centrality bins: …”  here “or” must 
be typo. Right?
8. Line240-243: “Due to imperfect calibration, the peak of the nσe 
distribution is found to deviate from the expected value of 0 and the 
deviation depends on track η…. to 0 across track η.” it is not useful to 
mention this in the paper. Preferably dropping  it. We could just 
mention “systematic uncertainty due to detector calibration…” or 
something similar direction.
9. Result section: we need a bit more discussion of “Tsinghua (THU) 
model”
10. Line343-345: “The fraction of regenerated J/ψ in the model decreases 
from approximately 50% in central collisions to less than 5% in 
peripheral collisions”
11. L391-393: “They are also found to be well described by a transport 
model calcuation for prompt J/ψ, in which regenerated J/ψ is assumed to 
be unpolarized.” It sounds like this model even using polarised prompt 
J/psi can reproduce the unpolarised J/Psi observation in the data as it 
is mentioned “well described by a transport model calcuation for prompt 
J/ψ”.  is not it a self contradicting?
12. L233: “the ratio between electrons matched to the TOF...” Better to 
mention “electrons from TPC matched …”
13. Results section L389-393: here two points 1) Isobar data good 
agreement with p+p and 2) consistent with transport model  with dominant 
prompt J/psi ; physics conclusion is not clear here. What we are trying 
to say here.  Are we going to say these “prompt J/psi produced in isobar 
collision are unpolarised” .
14. L393: “These results provide further insights into J/ψ production 
and propagation in the QGP”; it is not clear how? Need to expand it.
15. 15. How do you get this equation.6. if you have derived, then please 
elaborate this in AN (Eq.24).

AN:
1. Fig.19: Do we understand why tof matching efficiency is smaller for 
|eta|<0.8 than 1.0?  should not it be otherwise or approximately the 
same?
2. Please correct Equation 21. Closing Bracket is missing in the first 
term.


Thank you
Nihar



On 2025-02-14 14:18, ShenDandan2024 AT outlook.com wrote:
> Dear Nihar and Isaac,
>
> I wanted to inform the you that the website has been fixed.
>
> I’m looking forward to your feedback on my PWG review and truly
> appreciate your time and insights!
>
> Thanks again, and I really appreciate your patience.
>
> Best regards,
> Dandan
>
> 发件人: star-hp-l-request AT lists.bnl.gov
> <star-hp-l-request AT lists.bnl.gov> 代表 Nihar Sahoo
> <nihar AT rcf.rhic.bnl.gov>
> 日期: 星期五, 2025年2月7日 07:25
> 收件人: star-hp-l AT lists.bnl.gov <star-hp-l AT lists.bnl.gov>
> 抄送: Dandan Shen <shendandan AT mail.sdu.edu.cn>, Isaac
> <isaac.mooney AT yale.edu>
> 主题: Re: [[Star-hp-l] ] Measurement of inclusive J/ψ polarization
> in Ru+Ru and Zr+Zr collisions at √(S_NN) = 200 GeV at STAR is Ready
> for PWG Review
>
> Hello Dandan,
>
> I have quickly looked at your paper webpage.
>
> https://drupal.star.bnl.gov/STAR/blog/dshen1/Measurements-of%C2%A0JPsi%C2%A0polarization-in%C2%A0RuRu%C2%A0and%C2%A0ZrZr%C2%A0collisions-at%C2%A0200-GeV-STAR
>
> There are some plots not pertaining to your analysis. Can you please
> correct me if I am misunderstood it?
>
> Thank you
> Nihar
>
> On 2025-02-06 18:55, Nihar Sahoo wrote:
> > Hello Dandan,
> >
> > Yes, i have your paper materials in my todo list but due to my
> > semester teaching and other work i am unable to read this week.
> > But i plan to go through these materials and send my comments by
> coming
> > week.
> >
> > Thank you for your patience.
> >
> > Best
> > Nihar
> >
> >
> >
> > On 2025-02-06 17:06, Dandan Shen wrote:
> > > Dear Nihar and Isaac,
> > >
> > > Just wanted to gently follow up and check if you've had a chance to
> > > look over the paper draft and analysis note.
> > >
> > > Webpage:
> https://drupal.star.bnl.gov/STAR/blog/dshen1/Measurements-of%C2%A0JPsi%C2%A0polarization-in%C2%A0RuRu%C2%A0and%C2%A0ZrZr%C2%A0collisions-at%C2%A0200-GeV-STAR
> [1]
> > > Paper draft:
> https://drupal.star.bnl.gov/STAR/system/files/JPsi_polarization_paper__v0-3_0.pdf
> [2]
> > > Note:
> https://drupal.star.bnl.gov/STAR/system/files/Note_Dandan_JpsiPolarization-4_0.pdf
> [3]
> > > I really appreciate your time and feedback—thank you so much!
> > >
> > > Best,
> > > Dandan Shen (on behalf of PAs)
> > >
> > > From: Dandan Shen <shendandan AT mail.sdu.edu.cn>
> > > Date: 2025-01-20 15:28:44
> > > To:HP group <star-hp-l AT lists.bnl.gov>,Nihar
> > > <nihar AT rcf.rhic.bnl.gov>,Isaac <isaac.mooney AT yale.edu>,Qian Yang
> > > <tc88qy AT rcf.rhic.bnl.gov>
> > > cc: "li.yi" <li.yi AT sdu.edu.cn>,Rongrong <marr AT bnl.gov>
> > > Subject: Re:Re:Measurement of inclusive J/ψ polarization in Ru+Ru
> and
> > > Zr+Zr collisions at √(S_NN) = 200 GeV at STAR is Ready for PWG
> > > Review
> > >
> > > > Dear HPs,
> > > >
> > > > Just a gentle reminder to check in and see if you’ve had a
> chance
> > > > to review the paper draft and analysis note.
> > > >
> > > > Thanks so much for your time!
> > > >
> > > > Best regards,
> > > > Dandan Shen (on behalf of PAs)
> > > >
> > > > From: Dandan Shen <shendandan AT mail.sdu.edu.cn>
> > > > Date: 2025-01-13 15:09:13
> > > > To:HP group <star-hp-l AT lists.bnl.gov>,Nihar
> > > > <nihar AT rcf.rhic.bnl.gov>,Isaac <isaac.mooney AT yale.edu>,Qian Yang
> > > > <tc88qy AT rcf.rhic.bnl.gov>
> > > > cc: Rongrong <marr AT bnl.gov>,"li.yi" <li.yi AT sdu.edu.cn>
> > > > Subject: Re:Measurement of inclusive J/ψ polarization in Ru+Ru
> and
> > > > Zr+Zr collisions at √(S_NN) = 200 GeV at STAR is Ready for PWG
> > > > Review
> > > >
> > > > Dear HPs,
> > > >
> > > > Following up on my previous email, the paper draft and analysis
> note
> > > > have been updated as follows:
> > > >
> > > > Webpage:
> https://drupal.star.bnl.gov/STAR/blog/dshen1/Measurements-of%C2%A0JPsi%C2%A0polarization-in%C2%A0RuRu%C2%A0and%C2%A0ZrZr%C2%A0collisions-at%C2%A0200-GeV-STAR
> [1]
> > > > Paper draft:
> https://drupal.star.bnl.gov/STAR/system/files/JPsi_polarization_paper__v0-3_0.pdf
> [2]
> > > > [1]
> > > >
> > > > Note:
> https://drupal.star.bnl.gov/STAR/system/files/Note_Dandan_JpsiPolarization-4_0.pdf
> [3]
> > > > [2]
> > > >
> > > > We kindly request your review of these documents and would greatly
> > > > appreciate your valuable comments and suggestions.
> > > >
> > > > Thank you for your time and support.
> > > >
> > > > Best regards,
> > > > Dandan Shen (on behalf of PAs)
> > > >
> > > > From: Dandan Shen <shendandan AT mail.sdu.edu.cn>
> > > > Date: 2025-01-08 15:47:58
> > > > To:HP group <star-hp-l AT lists.bnl.gov>,Nihar
> > > > <nihar AT rcf.rhic.bnl.gov>,Isaac <isaac.mooney AT yale.edu>,Qian Yang
> > > > <tc88qy AT rcf.rhic.bnl.gov>
> > > > cc: Rongrong <marr AT bnl.gov>,"li.yi" <li.yi AT sdu.edu.cn>
> > > > Subject: Measurement of inclusive J/ψ polarization in Ru+Ru and
> > > > Zr+Zr collisions at √(S_NN) = 200 GeV at STAR is Ready for PWG
> > > > Review
> > > >
> > > > Dear HPs,
> > > >
> > > > The paper draft and analysis note for _“Measurement of inclusive
> > > > J/ψ polarization in Ru+Ru and Zr+Zr collisions at √(S_NN) = 200
> > > > GeV at STAR”_ are now ready for PWG review.
> > > >
> > > > You can find the relevant documents at the following links:
> > > >
> > > > Webpage:
> https://drupal.star.bnl.gov/STAR/blog/dshen1/Measurements-of%C2%A0JPsi%C2%A0polarization-in%C2%A0RuRu%C2%A0and%C2%A0ZrZr%C2%A0collisions-at%C2%A0200-GeV-STAR
> [1]
> > > > Paper
> draft:https://drupal.star.bnl.gov/STAR/system/files/JPsi_polarization_paper__v0-3.pdf
> > > > Analysis note:
> https://drupal.star.bnl.gov/STAR/system/files/Note_Dandan_JpsiPolarization-4.pdf
> [4]
> > > > [3]
> > > >
> > > > We kindly request your review of these documents and would greatly
> > > > appreciate your valuable comments and suggestions.
> > > >
> > > > Thank you for your time and support!
> > > >
> > > > Best regards,
> > > > Dandan Shen on behalf of PAs
> > >
> > >
> > >
> > > Links:
> > > ------
> > > [1]
> https://drupal.star.bnl.gov/STAR/system/files/JPsi_polarization_paper__v0-3_0.pdf
> [2]
> > > [2]
> https://drupal.star.bnl.gov/STAR/system/files/Note_Dandan_JpsiPolarization-4_0.pdf
> [3]
> > > [3]
> https://drupal.star.bnl.gov/STAR/system/files/Note_Dandan_JpsiPolarization-4.pdf
> [4]
>
> Links:
> ------
> [1] 
> https://drupal.star.bnl.gov/STAR/blog/dshen1/Measurements-of%C2%A0JPsi%C2%A0polarization-in%C2%A0RuRu%C2%A0and%C2%A0ZrZr%C2%A0collisions-at%C2%A0200-GeV-STAR
> [2] 
> https://drupal.star.bnl.gov/STAR/system/files/JPsi_polarization_paper__v0-3_0.pdf
> [3] 
> https://drupal.star.bnl.gov/STAR/system/files/Note_Dandan_JpsiPolarization-4_0.pdf
> [4] 
> https://drupal.star.bnl.gov/STAR/system/files/Note_Dandan_JpsiPolarization-4.pdf