STAR Flow, Chirality and Vorticity PWG

[Prithwish Tribedy <ptribedy AT rcf.rhic.bnl.gov>]

Hi Yicheng,
   I would like to sign-off your talk and move it to star-talks. I am OK 
to move with your current slides except for the one on R-correlator 
which needs polishing.

I find the linear correlations between 1/\sigma^2 and 1/Nch even after 
scaling by shuffled event width in isobar data and with AVFD simulation 
of 2203.10029. I believe there are some concerns that might lead to 
confusion. So, I suggest we go through a couple of iterations on slide 
#17 and polish the wordings.

https://drupal.star.bnl.gov/STAR/system/files/SQM2022_YichengFeng_v14.pdf


I’ll use “~” sign to indicate proportionality.

Left part:
“Normalized by shuffled width, so the N_ch is already scaled out”.
—But from both isobar data and the AVDF simulation of 2203.10029 we see 
that 1/\sigma^2 has a linear relation with 1/Nch.

“STAR has concluded that 1/\sigma^2 is approximately proportional to 
v_2”.
— But the isobar data do not show that from your plot.
Also, I am not sure if STAR concluded this. In the isobar paper we say 
Ref. [18] indicate an approximate scaling which is N* Δγ and based on 
that we quote a number 1.02.

“After v_2 scaling, the isobar ratio is even further below unity.”
— From your plot we do not see 1/\sigma^2 to be proportional to v_2 so 
we cannot scale it. This is based on the same argument that we can’t 
scale by 1/Nch.

Right part:
Top line says “an additional” which is not clear.

“The apparent 1/Nch dependence is not proportional, Why scale by 1/Nch 
?”
— This is not clear. They saw a linear dependence between 1/\sigma^2 vs 
1/Nch and applied a scaling. So are we saying they should have scaled by 
“a + b/Nch”  not by “1/Nch” ? Or are we saying they should have not done 
any scaling at all?

“The apparent 1/Nch dependence comes from 1/\sigma^2 ~ v_2, and v_2 
depends on N_ch”.
— From isobar data we do not see 1/\sigma^2 ~ v_2 so how can we say 
this?
I also have not seen an AVFD simulation plot showing 1/\sigma^2 ~v_2 — I 
have requested this before.

Also, “v_2 depends on Nch”
— this is correct. But its more like "v_2 ~ 1/√Nch.” So how can we say 
"1/\sigma^2 ~ v_2 ~ 1/Nch” ?


“From Zr+Zr to Ru+Ru 1/Nch decreases and v_2 increase.”
— This is not clear what we’re saying here. I guess we are saying that:

 1/\sigma = f(v_2, Nch) that is the width is probably a function of both 
v_2 and Nch but then the argument is not clear.

1/\sigma (Ru)/ 1/\sigma (Zr) =  f(v_2, Nch) (Ru) /  f(v_2, Nch) (Zr)

And we know  v_2(Ru) > v_2(Zr)  and also 1/Nch(Ru)< 1/Nch(Zr) but then 
what ?

“Lacey et al. conclusion by 1/Nch scaling contradicts STAR’s conclusion”
— Not clear which STAR conclusion is being contradicted. The conclusion 
of the STAR paper was “no predefined criteria for CME was observed in 
blind analysis which includes 1/\sigma^2 ratio to be less than unity”. 
We’re not saying that here. In the post-blind section we have a baseline 
for 1/\sigma^2 which is N* Δγ = 1.02 for 20-50%. However, it is based on 
the scaling relations extracted in Ref. [18]. So are we saying that the 
baseline extracted in the post-blind section is contradicted. What if 
someone says it was a naive baseline and 2203.10029 presents an updated 
baseline based on AVFD. This needs some polishing.

Best,
Prithwish



On 2022-06-01 22:19, Yicheng Feng via Star-cme-focusgroup-l wrote:
> Hi All,
>
> I have uploaded a new version of slides to the same node:
> https://drupal.star.bnl.gov/STAR/node/59776
>
> where one new slide (page 17) is added for the R observable.
>
> Sincerely,
>
> Yicheng
>
> -------------------------
>
> From: Star-fcv-l <star-fcv-l-bounces AT lists.bnl.gov> on behalf of
> webmaster--- via Star-fcv-l <star-fcv-l AT lists.bnl.gov>
> Sent: Monday, May 30, 2022 5:36 PM
> To: star-fcv-l AT lists.bnl.gov <star-fcv-l AT lists.bnl.gov>
> Subject: [Star-fcv-l] STAR presentation by Yicheng Feng for SQM 2022
> submitted for review
>
> Dear star-fcv-l AT lists.bnl.gov members,
>
> Yicheng Feng (feng216 AT purdue.edu) has submitted a material for a
> review,
> please have a look:
> https://drupal.star.bnl.gov/STAR/node/59776
>
> ---
> If you have any problems with the review process, please contact
> webmaster AT www.star.bnl.gov
> _______________________________________________
> Star-fcv-l mailing list
> Star-fcv-l AT lists.bnl.gov
> https://lists.bnl.gov/mailman/listinfo/star-fcv-l
> _______________________________________________
> Star-cme-focusgroup-l mailing list
> Star-cme-focusgroup-l AT lists.bnl.gov
> https://lists.bnl.gov/mailman/listinfo/star-cme-focusgroup-l