STAR Flow, Chirality and Vorticity PWG

[Yicheng Feng <feng216 AT purdue.edu>]

Hi FCV Convenors and All,

We had a PWGC preview last month for our study about Lambda-CME correlations, 

and we got valuable preview comments from PWGC. 

After that meeting, we did some homework and crosschecks accordingly,

and then prepared a reply to those comments. 

Please see the details through the link:

https://drupal.star.bnl.gov/STAR/system/files/ReplyPwgcPreviewCorLamCme20220722_v2.pdf

Other materials (note, draft, figurers) are also updated to the webpage:

https://drupal.star.bnl.gov/STAR/blog/fengyich/Correlation-between-Lambda-and-CME-Webpage

If you have any further comments, please let me know.

Sincerely,

Yicheng

---

From: Star-fcv-l <star-fcv-l-bounces AT lists.bnl.gov> on behalf of Takafumi Niida via Star-fcv-l <star-fcv-l AT lists.bnl.gov>
Sent: Friday, July 22, 2022 3:05 PM
To: star-fcv-l AT lists.bnl.gov <star-fcv-l AT lists.bnl.gov>
Subject: [Star-fcv-l] Notes for PWGC preview (7/22/2022): Event-by-event correlations between Lambda (anti-Lambda) hyperon measurements and the chiral magnetic effect

 

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Date: Jul/22/2022

Participants: Yicheng Feng, Evan Finch, Fuqiang Wang, Daniel Cebra, Hanna Zbroszczyk, Maria Zurek, Nihar Sahoo, Sooraj Radhakrishnan, Subhash Singha, Xiaofeng Luo, Xiaoxuan Chu, Yi Yang, Rongrong Ma, Takafumi Niida

Title: Event-by-event correlations between Lambda (anti-Lambda) hyperon measurements and the chiral magnetic effect observables in Au+Au collisions at \sqrt{s_{NN}} = 27 GeV from STAR

PAs: Yicheng Feng, Evan Finch, Fuqiang Wang

Target journal: PRC

Proposal page: https://drupal.star.bnl.gov/STAR/blog/fengyich/Correlation-between-Lambda-and-CME-Webpage

Presentation: https://drupal.star.bnl.gov/STAR/system/files/PwgcPreviewCorrLamCme20220627.pdf

The PWGC panel previewed a paper proposal from FCV PWG. The panel thinks that analysis is mature and the paper should move forward, and the target journal is appropriate. The following points were discussed.

s12 and s19

Q. PAs mentioned that the results are in good agreement with other analyses which are also ongoing toward publication. But there seems small difference even for the same observables with the same dataset. What does it come from and the difference is included in the systematic uncertainty?

A. For delta-gamma, slight different cuts were used. For polarization, the results are very close but need to compare with final results that are now posted in PWG. Since the results are close, not in the systematic uncertainty.

C. For both delta-gamma and polarization, we as STAR don’t want to publish two sets of results for same observables with sam data. It will make confusion and there may be third results requested which we want to avoid.

A. PAs agree that those individual same results should not be be published. 

C. In the paper, PAs can mention that the results are consistent with other papers within errors.

Q. Regarding the polarization splitting, is it also consistent with Joey’s paper in terms of sign. Probably the results will be consistent within error though.

A. PAs will check on this.

Q. For delta-gamma, did PAs use full EPD or inner/outer EPD as done in Yu/Prithwish’s analysis? Which result is compared here?

A. Full EPD was used in this analysis. Our result is compared with their result using full EPD.

Q. Delta-P is consistent with zero. Also no CME in CME paper. Do you still expect to see something? If so, is it consistent?

A. Delta-P is event average, but the covariance measured in EbE basis may have more sensitivity and could lead to larger signal. But it is difficult to calculate upper limit and sensitivity since we do not have any model for this observable.

s16

C. Delta-n should be zero but we see non-zero values which are due to detector effect. This is not physics quantity but detector specific quantity. This needs to be clearly written in the caption and main texts.

s23

Q. Current conclusion in slide 23 has no clear statement on physics. Can we understand that there is no CME with this technique in this energy which is consistent with all other papers?

A. Yes