STAR Flow, Chirality and Vorticity PWG

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

Hi Yu, 

Thank you for your email. 

The isobar blind analysis (PhysRevC.105.014901) had the observed fcme measured from the SP/PP method before nonflow correction (20-50% centrality). 

Ru+Ru: fcme = (29 +/- 13 +/- 1)%

Zr+Zr: fcme = (6 +/- 8 +/- 2)%

where the uncertainty is large. 

Sincerely,

Yicheng

---

From: star-fcv-l-request AT lists.bnl.gov <star-fcv-l-request AT lists.bnl.gov> on behalf of Hu, Yu <yuhu AT bnl.gov>
Sent: Monday, November 18, 2024 8:17 PM
To: Feng, Yicheng <feng216 AT purdue.edu>
Cc: Star-fcv-l AT lists.bnl.gov <star-fcv-l AT lists.bnl.gov>
Subject: Re: [[Star-fcv-l] ] [[Starpapers-l] ] Notes for PWGC preview (11/15/2024): Evidence of Possible Chiral Magnetic Effect in Au+Au Collisions at √sNN=200 GeV at the Relativistic Heavy Ion Collider

 

---- External Email: Use caution with attachments, links, or sharing data ----

Dear Yicheng, 

Congratulations on the nice study. I have one question maybe related, could you please remind me the f_cme for the individual isobar (not the ratio between Ru and Zr)? Since they are using a similar method and at the same energy.

Thank you.

Best,

Yu

---

From: starpapers-l-request AT lists.bnl.gov <starpapers-l-request AT lists.bnl.gov> on behalf of Sooraj Radhakrishnan <skradhakrishnan AT lbl.gov>
Sent: Monday, November 18, 2024 11:30
To: STAR Flow, Chirality and Vorticity PWG <star-fcv-l AT lists.bnl.gov>; STAR Papers Discussion List <starpapers-l AT lists.bnl.gov>
Subject: [[Starpapers-l] ] Notes for PWGC preview (11/15/2024): Evidence of Possible Chiral Magnetic Effect in Au+Au Collisions at √sNN=200 GeV at the Relativistic Heavy Ion Collider

 

Date: 11/15/2024

Participants: 

Fuqiang Wang, Yicheng Feng, Ting Lin, Xiaoxuan Chu, Hanna Zbroszczyk, Nu Xu, Prithwish Tribedy, Richard Seto, Subhash Singha, Isaac Mooney, Nihar Sahoo, Qian Yang, (Tommy) Chun Yuen Tsang, Yue Hang Leung, Barbara Trzeciak, ShinIchi Esumi, Sooraj Radhakrishnan

Title: Evidence of Possible Chiral Magnetic Effect in Au+Au Collisions at √sNN=200 GeV at the Relativistic Heavy Ion Collider

PAs: Yicheng Feng, Haojie Xu, Jie Zhao, Fuqiang Wang 

Target journal: PRL

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

Presentation: https://drupal.star.bnl.gov/STAR/system/files/Fcme20241115_PWGC_preview_v2.pdf

The PWGC panel previewed a paper proposal from FCV PWG. The panel found that the analysis is mature and results are important and interesting, and the paper should move forward. The journal choice was also found to be appropriate. The following points were discussed.

Q: S5 - What is v2 in the first equation here?

A: It is the true flow, including the flow fluctuations, terms in blue, red and green on S6

Q: S6 - Why does the v2 drop at very small delta eta?

A: It is because of acceptance effects like track merging 

Q: Do you have the three particle correlation measurements from p+p?

A: No, we use different model calculations to evaluate the value and systematics  

Q: S15 - Arent the differences of values second and third rows to default included in systematics?

A: Yes, we dont plan to include these in the final tables for the paper 

Q: Figure 3 right panel - the centrality dependence of CME signal is very weak, is this expected 

A: It is not clear what the centrality dependence should be. Also the error bars are large to make conclusions  

Q: S5 - What does jet mean here? Are these low pT tracks or matched to a hard object?

A: These are from low pT tracks. These are just sources of non-flow, we dont reconstruct jets 

Q: What is the difference between Fig1 and Fig3?

A: Fig3 is with the non-flow contributions subtracted. We will label properly 

Q: Can some lower level data, for e.g 'a' or 'A' be included in the paper?

A: Yes, we will think about this. These were published in the previous PRL 

Q: S6 - is the fitted curve shown in the figure?

A: Yes, it is the black curve
Q: There is no black curve at very small delta eta

A: Yes, this region is excluded from the fit

Q: S6 - why do you need two Gaussians to fit the data?

A: We find this can better describe the data 

Q: Fig2 - where is the true v2 here from?

A: This is from the fit shown in S6 

Q: Should you use any model that includes flow, like hydro or AMPT in calculating 3p correlations?

A: We want to evaluate the non-flow contributions
Q: These models dont include modifications to 3p correlations from transport and interactions. Can AMPT or similar models from peripheral collisions be checked to see impact?
A: We could. But there is also flow in these collisions 
C: (Comment from Isaac who had to leave) Probably not a good idea to use PYTHIA as is for evaluation of 3p correlations
C: PAs will follow up on suggestions with Isaac

Q: S4 - why use global for 2011 and primary for 2014? Also why different Vz cuts?

A: These are because of presence of HFT is 2014 data 

Q: S5 - in the bottom equation, what part contains the signal?

A: Signal contribution is in 'A'

Q: S6 - p1 and F2 are coefficients of DeltaEta, how can they be distinguished? 

A: These are not from fit to V2(DeltaEta) shown, but are fixed from other measurements 

Q: S8 - what are the systematics in 3p from? Are they from models?

A: Yes, they are from using different models 

Q: Figure 3 - Why not indicate the value in 20-50% centrality range quoted in the abstract here?

A: Yes, we will
Q: Can we also indicate the value in all centrality range
A: Yes, we can  

Q: Figure 3 - Do you need the right plot? 

A: We can move it to the acceptance 
C: Could be better to change the x-axis of right plot to centrality or total multiplicity
A: Yes, we will consider 

Q: S15 - What is the purpose of using sub-event method? Does this need to be shown?

A: We will think about it 

Q: Title - Why 'Evidence of Possible', what does it mean?
A: We kept it so to be cautious. We will think about other options

Q: Abstract - sentences too long, please break them down. Can reduce jargons
A: Yes we will 

Q: How much of the uncertainties is from the 3p correlations? Are they dominant?
A: The statistical uncertainties are dominant 

Q: What does negative values for f_CME on Fig 3 mean?
A: This would indicate over-subtraction. But is zero within statistical uncertainties 

Q: Why more central events are not shown?
A: This is because of poor event plane resolution and thus very large statistical uncertainties 

Q: What is new in going from Fig-1 to Fig-3? Do we need STAR data from this? Can this be a model paper based on 2022 PRL?
A: Yes, we need STAR data for the non-flow subtraction 

--

Sooraj Radhakrishnan

Research Scientist,

Department of Physics

Kent State University

Kent, OH 44242

Physicist Postdoctoral Affiliate

Nuclear Science Division
Lawrence Berkeley National Lab
MS70R0319, One Cyclotron Road

Berkeley, CA 94720

Ph: 510-495-2473

Email: skradhakrishnan AT lbl.gov