STAR Flow, Chirality and Vorticity PWG

["Feng, Yicheng" <feng216 AT purdue.edu>]

Hi Shengli, 

Thank you for your comments. 

1. Track Merging Effect.

It would be helpful to show the results with ∣Δηa,b∣>0.2 or even >0.4 for both v2{2} and c3p, as your Fig. 2 still indicates a significant track merging effect. I am concerned about whether this could influence your conclusions. If you have results with larger ∣Δη∣>0.2 or >0.4 for Fig. 1, Fig. 2, and Fig. 3, it would be extremely helpful to include them.

I think you might have some misunderstanding on the v2 nonflow estimate. 

We apply Δη cut only on the ∆γ measurements (line 184-186), but not on the v2 measurements on Fig.2. 

The 1D fit method will take care of that and make sure that the flow component is free from tracking merging or other nonflow effects. 

For example, Fig.A2, the inclusive measurement (red) and nonflow estimate (brown) include the track merging effect, while the estimated flow component (blue) should not be affected. 

On Fig.A1, we can see the track merging effect is negligible at Δη>0.1.

2. Nonflow Estimation:

For the nonflow corrections, you used a 1-D fit for v2{2} and HIJING for c3p. It is essential to demonstrate whether these approaches are effective. I suggest:

* Adding the real data c3p to Fig. 2(b) for direct comparison.

That comparison has already been made, please check Fig.B2 and Fig.S3 and the corresponding discussions in the text.

* Including nonflow estimations for v2{2} by comparing HIJING with real data and aligning these with the 1-D fit results.

That's a good point. We added some plots to the analysis note (page 33-34):

https://drupal.star.bnl.gov/STAR/system/files/AuAuFcme_Note_Pwg_v4.pdf 

We made some plots to compare the nonflow estimate from data with the HIJING model v2{2}^2 (which does not have flow). They agree well with each other. 

Since model and data (corrected by efficiency) have slightly different multiplicity of POI, we also compared N*v2{2}^2. The agreement is better. 

Sincerely,

Yicheng

---

From: star-fcv-l-request AT lists.bnl.gov <star-fcv-l-request AT lists.bnl.gov> on behalf of Shengli Huang <star-fcv-l AT lists.bnl.gov>
Sent: Friday, November 22, 2024 5:51 PM
To: star-fcv-l AT lists.bnl.gov <star-fcv-l AT lists.bnl.gov>
Subject: Re: [[Star-fcv-l] ] AuAu 200GeV CME paper draft and analysis note

 

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Dear Yicheng,

Thank you for sharing these results. I have two comments:

1. Track Merging Effect:
   It would be helpful to show the results with ∣Δηa,b∣>0.2 or even >0.4 for both v2{2} and c3p, as your Fig. 2 still indicates a significant track merging effect. I am concerned about whether this could influence your conclusions. If you have results with larger ∣Δη∣>0.2 or >0.4 for Fig. 1, Fig. 2, and Fig. 3, it would be extremely helpful to include them.

2. Nonflow Estimation:
   For the nonflow corrections, you used a 1-D fit for v2{2} and HIJING for c3p. It is essential to demonstrate whether these approaches are effective. I suggest:

   • Adding the real data c3p to Fig. 2(b) for direct comparison.
   • Including nonflow estimations for v2{2} by comparing HIJING with real data and aligning these with the 1-D fit results.

This would help strengthen the case for the nonflow subtraction procedure and make it more convincing for the referee.

I hope these suggestions are helpful!

Best regards,
Shengli

On Fri, Nov 22, 2024 at 2:08 PM Feng, Yicheng <feng216 AT purdue.edu> wrote:

Hi FCV, 

We had a PWGC preview of the CME paper proposal and got many valuable comments. We’ve documented it here: 

https://drupal.star.bnl.gov/STAR/system/files/AuAuFcme_Pwgc_Preview.pdf

We have prepared a paper draft and analysis note. 

paper draft: https://drupal.star.bnl.gov/STAR/system/files/AuAuFcme_Paper_Pwg_v4.pdf

analysis note: https://drupal.star.bnl.gov/STAR/system/files/AuAuFcme_Note_Pwg_v4.pdf

More details can also be found on the drupal webpage: 

https://drupal.star.bnl.gov/STAR/blog/fengyich/fcme-AuAu-200-GeV-after-background-estimate

If you have any questions/comments, please let us know.

Sincerely,

Yicheng