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star-fcv-l - Re: [Star-fcv-l] FCV PWG meeting on 7/July/2021 Wed. 9:30AM at BNL

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Subject: STAR Flow, Chirality and Vorticity PWG

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  • From: ASHIK IKBAL <ashikhep AT gmail.com>
  • To: Sooraj Radhakrishnan <skradhakrishnan AT lbl.gov>
  • Cc: "STAR Flow, Chirality and Vorticity PWG" <star-fcv-l AT lists.bnl.gov>
  • Subject: Re: [Star-fcv-l] FCV PWG meeting on 7/July/2021 Wed. 9:30AM at BNL
  • Date: Thu, 22 Jul 2021 13:05:14 -0400

Hi Sooraj,

Thanks for the reference of the model calculation of D-Dbar Delta v1. I agree with you that the sign of the Delta v1 depends on the interplay of the electric and magnetic components. And in reality the situation might be more complicated due to many other effects.

Now, regarding the mass scaling part, by saying similar mass I mean the mass of LHS and RHS of each combination is the same at the partonic level. When you calculate the mass at the partonic level of the combinations you have to include the pre-factors in the sum as well. e.g., in the combination K- + 1/3 pbar - Lambda-bar, I used the pre-factor 1/3 before p-bar to take one u-bar contribution from p-bar (assuming u-bar and d-bar have the same mass). The mass scaling you are talking about here is already included. Since the way we combine the particles considers this fact.

 At yesterday's discussion in the BNL group meeting, you asked about the y and pT dependence of the individual particles I am using in my analysis. I showed them already at the PWG meeting last year.  For convenience, I have put them on a slide together.  Please have a look: https://drupal.star.bnl.gov/STAR/system/files/v1_y_pt_producedpart_ashik.pdf

Thanks,
Ashik



On Tue, Jul 20, 2021 at 11:07 PM Sooraj Radhakrishnan <skradhakrishnan AT lbl.gov> wrote:
Hi Ashik,
   Thanks for the replies. The predicted sign for the Delta v1 at 200 GeV is negative, for example see for D-Dbar here https://arxiv.org/pdf/2009.11066.pdf. But this again depends on the interplay of the electric and magnetic components. Its a time varying magnetic field, so that has a big impact. But these are calculations, so could be either way in reality

For the mass scaling part when you say similar mass, do you mean with the formula including the pre-factors in the sums? My question was, say in your formula K- + 1/3 pbar - Lambda, you are underweighting pbar and so basically combining K- and Lambda. If there is a mass scaling between K- and Lambda, would that affect your conclusions?

thanks
Sooraj

On Mon, Jul 12, 2021 at 9:00 AM ASHIK IKBAL <ashikhep AT gmail.com> wrote:
Hi Sooraj,

Thanks for your email. Here are my responses:

The v1 for positive as well negative charge is negative at positive rapidity - at least for the sqrt {s_NN} studied here. You can have a look at (at 27 and 54.4 GeV): https://drupal.star.bnl.gov/STAR/system/files/STARprelim_BulkCorr016102019.pdf

It's true that the magnetic field affects the v1 for positive and negative charge. But, one should keep in mind that the real scenario is much more complicated due to transport for beam rapidity and other effects like Coulomb, etc.  In our analysis, the Delta v1 is not calculated by simply subtracting v1 b/w positive and negative particles (except v1(omegabar) - v1(omega)), rather by subtracting v1 b/w combinations of produced particles. The combinations have different charge differences. The Delta v1 slope increases with charge differences at 27 GeV and I think it is consistent with the deflection from the magnetic field.

Now in my slide 39, I showed the pT/nq dependence of 2 combinations having identical quark contents ((charge diff is zero).). This a test for the coalescence inspired sum rule with pT/nq. You can see that the sum rule holds very well at the intermediate pT region to the pT region shown here. However, at very low pT, there is a difference. While in slide 42, I showed the pT/nq dependence where there are non-identical quark combinations (charge diff is non-zero). So, one should not expect the agreement in the region where there was an agreement for the identical quark content case before. In the other words, this is a violation of the sum rule for non-zero charge diff. 

Our conclusion of the Delta v1 slope is based on the rapidity dependent study. It is important to mention that we curved out the same phase space (pT/nq-y) region for every particle in our analysis. In this way, we already have the lower pT/nq cut in our analysis. 

Regarding the mass scaling effect on flow, I would say there is an effect of mass on the flow. This is respected in our measurements. We combine different produced particles in such a way that the combinations have the same mass at the partonic level.

Let me know if you need further clarifications.

Best,
Ashik

On Fri, Jul 9, 2021 at 3:28 PM Sooraj Radhakrishnan <skradhakrishnan AT lbl.gov> wrote:
Hi Ashik,
   These are nice studies and interesting results. Can I ask a couple of questions/clarifications?

Is the sign of the observed Delta v1 consistent with the deflection from a magnetic field? Shouldnt the v1 from the magnetic field be negative for a positive charge at positive rapidity?
I see on your slides 39, 42 that the pT dependences are not trivial. Do you understand these? In 39, there is a difference at low pT, while in 42 its mostly at high pT. So if you have a lower pT cut, would it change your conclusions?
When you add the v1 and select the pT ranges, would any mass scaling effects affect the flow values? At low momenta, there is also mass scaling in addition to quark number scaling

thanks
Sooraj



On Wed, Jul 7, 2021 at 6:16 AM ASHIK IKBAL via Star-fcv-l <star-fcv-l AT lists.bnl.gov> wrote:

On Wed, Jul 7, 2021 at 4:26 AM Niseem via Star-fcv-l <star-fcv-l AT lists.bnl.gov> wrote:

Hi All,

Please find my slides at this link,

https://www.star.bnl.gov/protected/bulkcorr/niseem/pwg_2021/ptpt_model_data_3.pdf

Thanks,
Niseem


On 7/6/21 4:49 AM, knayak via Star-fcv-l wrote:

Dear Conveners,


    I would like to give the paper proposal “Directed flow of identified hadrons in Au+Au collisions at 19.6, 27 

and 54.4 GeV in STAR”. Could you please add my name in the agenda?

Thanks,
With best regards
Kishora

 Original Message 
Sender: ShinIchi Esumi via Star-fcv-l<star-fcv-l AT lists.bnl.gov>
Recipient: Chirality and Vorticity PWG" <star-fcv-l AT lists.bnl.gov>
Date: Monday, Jul 5, 2021 18:52
Subject: [Star-fcv-l] FCV PWG meeting on 7/July/2021 Wed. 9:30AM at BNL

Dear FCV PWG colleagues 

We will have our weekly FCV PWG meeting on this Wednesday morning 7/July/2021 
9:30AM in BNL (NY time zone) at our usual time and place. So if you have anything to 
present, please let us know and please post your slide by Tuesday. The zoom room link, 
ID and pass for the FCV PWG meeting are in our usual drupal agenda page below. 
Please also keep in mind that all the preliminary plots should have already been there 
in the summary area below. 

Best regards, Jiangyong, Prithwish and ShinIchi 

Meeting agenda page with zoom link : https://drupal.star.bnl.gov/STAR/blog/jjiastar/bulkcorr 
Preliminary page : https://drupal.star.bnl.gov/STAR/pwg/bulk-correlations/bulkcorr-preliminary-summary

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--
Ashik Ikbal
Research Associate
Kent State University
Department Of Physics
Kent, OH 44242, USA
Contact no.s: +1 631-504-7647 (USA)
                      +91 8250216234 (India)
Alternate e-mails: asheikh2 AT kent.edu
                             ashik AT rcf.rhic.bnl.gov
                             ashik.ikbal.sheikh AT cern.ch
_______________________________________________
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--
Sooraj Radhakrishnan
Research Scientist,
Department of Physics
Kent State University
Kent, OH 44243

Physicist Postdoctoral Affiliate
Nuclear Science Division
Lawrence Berkeley National Lab
MS70R0319, One Cyclotron Road
Berkeley, CA 94720
Ph: 510-495-2473


--
Ashik Ikbal
Research Associate
Kent State University
Department Of Physics
Kent, OH 44242, USA
Contact no.s: +1 631-504-7647 (USA)
                      +91 8250216234 (India)
Alternate e-mails: asheikh2 AT kent.edu
                             ashik AT rcf.rhic.bnl.gov
                             ashik.ikbal.sheikh AT cern.ch


--
Sooraj Radhakrishnan
Research Scientist,
Department of Physics
Kent State University
Kent, OH 44243

Physicist Postdoctoral Affiliate
Nuclear Science Division
Lawrence Berkeley National Lab
MS70R0319, One Cyclotron Road
Berkeley, CA 94720
Ph: 510-495-2473


--
Ashik Ikbal
Research Associate
Kent State University
Department Of Physics
Kent, OH 44242, USA
Contact no.s: +1 631-504-7647 (USA)
                      +91 8250216234 (India)
Alternate e-mails: asheikh2 AT kent.edu
                             ashik AT rcf.rhic.bnl.gov
                             ashik.ikbal.sheikh AT cern.ch



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