STAR Flow, Chirality and Vorticity PWG

["Tang, Aihong" <aihong AT bnl.gov>]

Dear Yicheng,

Thank you for your post. We'd like to revisit a question regarding the strong assumption about global spin alignment and its behavior in PP and SP.

For the PP/SP method to be valid, one must assume that the \Delta rho_00 of the rho-meson reaches its maximum along PP, similar to the behavior of v2. While this assumption could be correct or incorrect, there are currently no measurements to either support or refute it. Could you kindly elaborate on the evidence supporting your statement that "Because it (global spin alignment) is an effect of spin-orbit coupling in the participant zone, such a contribution would behave also like the flow-induced background and thus be subtracted in this SP/PP method" ?

Thanks,

Aihong

On Nov 22, 2024, at 2:07 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