STAR Flow, Chirality and Vorticity PWG

[ASHIK IKBAL <ashikhep AT gmail.com>]

Hi Sooraj,

I think it is difficult to interpret the fact that the v1 for Lambda and proton largely overlaps, because apart from the associated production, there are other complicated factors involved. 

OTOH, the associated production is always associated with one u or d quark and hence the Lambda and K^+ directed flow would be affected. However, these two particles are not included in the analysis - The analysis is focused on the produced particles only. 

Could you please be more specific about how exactly the physics interpretation will be affected. 

Thanks,

Ashik

On Sat, Mar 19, 2022 at 2:21 PM Sooraj Radhakrishnan <skradhakrishnan AT lbl.gov> wrote:

Hi Ashik,

   One potential caveat in the interpretation of Delta v1 is that there is significant associated production of Lambda in the collisions. So for the purpose of v1, it is not clear if strange quarks can be treated as 'produced quarks'. It can already be seen from the data that v1 of Lambda largely overlaps with that of protons despite having one strange quark. 

thanks

Sooraj

On Thu, Mar 17, 2022 at 10:52 AM ASHIK IKBAL via Star-fcv-l <star-fcv-l AT lists.bnl.gov> wrote:

Dear Aihong,

Thanks for your suggestions. I will cite the references in the draft. The references I shared with you in my earlier email are from the PHSD authors. A year back, we had a communication with them regarding their model and they referred us those references for the EM field. 

We already have calculations from two models, AMPT and PHSD+EMF. One has an EM field and one doesn't have it. However it is good to have the PHSD w/o EMF calculations. We can write to the authors for the model calculations and can add more models in the future. Our GPC process can go in parallel.

Thanks,

Ashik 

On Wed, Mar 16, 2022 at 7:24 PM Tang, Aihong <aihong AT bnl.gov> wrote:

Hi, Ashik:

Thanks for the quick response. I believe I have previously read at least a couple of those papers you mentioned below, but I did not make the connection that they are for PHSD until now. I will read them again.

A quick follow up question, can we turn off EMF in PHSD and do a comparison ? By doing that we will know directly how the EM part affects the result.   There are many dynamics going on in a model, and we want to be sure that EM field is the driven factor that is responsible for the pattern.    

BTW, I would suggest to cite the references below, along with the existing two references, when talking about PHSD+EMF.

Thanks,

Aihong

On Mar 16, 2022, at 6:21 PM, ASHIK IKBAL <ashikhep AT gmail.com> wrote:

Dear Aihong,

The PHSD is a transport approach where the dynamically generated EM fields from hadrons as well as partons are incorporated.

Here the EM fields are included in the transport equations. See the following refs for details:

https://inspirehep.net/literature/893530
and further Refs:
https://inspirehep.net/literature/1080920
https://inspirehep.net/literature/1127379

Please let me know if you need more information.

Thanks,

Ashik

On Wed, Mar 16, 2022 at 5:19 PM Tang, Aihong via Star-fcv-l <star-fcv-l AT lists.bnl.gov> wrote:

Hi, Ashik and Prithwish :

Sorry if the following has been discussed before, I couldn't find it right away so let me ask here :  The cited two references for PHSD did not include EMF right ? Is there a published reference for PHSD+EMF ?  I wonder how the EMF was introduced, like what is the B profile and lifetime, how were the Hall, Faraday and Coulomb effects included in the consideration, and what is the electric conductivity used, etc. 

Thanks,

Aihong

On Mar 16, 2022, at 3:49 PM, Prithwish Tribedy via Star-fcv-l <star-fcv-l AT lists.bnl.gov> wrote:

Hi Fuqiang,
 I think we should avoid model dependent conclusion and concentrate on the data from the two analyses. I am happy to use EM-field effects as a motivation but not more.

1. The observation from Ashik's analysis is with the increase of electric charge (and also strangeness), we see larger v1 slitting. This is interesting as we know EM-field driven effects are proportional to the electric charge. EM-field has Hall + Faraday + Coulomb -- depending on which one dominates, the sign will be either positive or negative.

2. The observation from Diyu's analysis is that with the increase of centrality we see a sign change of v1 splitting. This is interesting as we know EM-field effects are strongly dependent on centrality. The transported quarks can only generate positive v1 splitting. So, in peripheral events when we see negative v1 splitting we can say this effect may be driven by EM-field (Hall + Faraday + Coulomb).

I don't see a contradiction as in 10-40% we can both have EM-field and transport both leading to positive v1 splitting for positive \Delta q depending on which effect Hall, Faraday or Coulomb dominates and how they change with energy. Model calculations are available but they could have limitations.

Best,
Prithwish






On 2022-03-15 18:36, Wang, Fuqiang via Star-fcv-l wrote:

Hi Ashik, Diyu,
Now I’m confused. Looking at both your results again, I observe:
-        \Delta v1 split is positive for positive \Delta q for
produced quarks in 10-40% centrality.
-        \Delta v1 split is positive for positive \Delta q also for
proton – antiproton in the same 10-40% centrality range.
-        However, \Delta v1 for proton – antiproton becomes negative
in more peripheral collisions.
>From Diyu’s presentation, EM-field model calculation is negative v1
for positive charge, increasing from central to peripheral. So
Diyu’s interpretation of his data is that the positive transport
proton v1 is overtaken by the strong negative shift from EM in
peripheral collisions.
However, what Ashik was saying is that the EM field effect is positive
v1 for positive charge.
So I do think there’s a contradiction, at least apparently, that
needs to be sorted out.
First off, the easy question:
Positive v1 is defined to be the direction of spectator nucleons at
positive rapidity, as I understand it. So positive v1 for transport
protons makes sense to me. Is Ashik’s positive v1 also defined to be
the direction of positive-rapidity nucleons?
Best regards,
Fuqiang
From: Star-fcv-l <star-fcv-l-bounces AT lists.bnl.gov> On Behalf Of ASHIK
IKBAL via Star-fcv-l
Sent: Tuesday, March 15, 2022 9:49 AM
To: 申迪宇 <dshen AT rcf.rhic.bnl.gov>
Cc: Prithwish Tribedy <ptribedy AT icloud.com>; STAR Flow, Chirality and
Vorticity PWG <star-fcv-l AT lists.bnl.gov>
Subject: Re: [Star-fcv-l] FCV PWG meeting on 6/Oct/2021 Wed. 9:30AM at
BNL
Hi Diyu,
Thanks for your email. Regarding the concern you brought to my
attention, my comments are as follows:
1. As you have already seen, the analysis is focused on the particles
containing produced quarks only. We combine particles in such a way
that the combinations have identical quark content on both sides to
test the coalescence sum rule. Once this sum rule is valid, we tried
to find combinations that have a net non-zero charge difference. In
the combinations, we use the strange baryons along with other produced
particles. When we combine particles, the combinations must have a net
strangeness. Similarly, they will also have a net baryon number. This
is an unavoidable consequence of quark quantum numbers. Here we have
seen the v1 splitting increases with increasing charge difference
which is due to the presence of em field. We have shown this splitting
with strangeness to make a point that the splitting also scales with
strangeness like it does with charge, since the charge and strangeness
is correlated here. For the sake of argument, I want to bring up the
splitting between D0 and D0-bar which is solely driven by the em field
even if the D0 and D0-bar combination has a net charmness quantum no.
We do not say that this splitting between D0 and D0-bar is due to the
net charmness.
I think the theoretical calculations you are talking about here is the
splitting between a particle and its antiparticle (e.g., p-pbar,
pi+-pi-, K+-K-) where there are transported quarks. For our case, the
difference is not simply between a particle and its antiparticle
rather a group of produced (anti-)particles. You can notice that we
also have the theoretical calculations (transport model calculations,
PHSD) presented in the paper that have the same pattern as we found in
the experiment. I think the pattern we found is consistent with the
transport model calculations.
2. Regarding the fitting of  \Delta v1 slope with \Delta q within a
constant \Delta S is a good idea indeed, but it is not feasible here.
This is because we only have 2 independent data points having the same
\Delta S and among them one has large uncertainty. From only 2 data
points it is really difficult to conclude anything. We discussed all
these points many times during my presentations within the PWG.
Please let me know if you have any further concerns.
Best,
Ashik
On Tue, Mar 15, 2022 at 4:15 AM 申迪宇 <dshen AT rcf.rhic.bnl.gov>
wrote:

Hi, Ashik and all,
As both of us are interested in the v1 splitting, and we all got
some interesting results, I want to bring out a discussion here.
Your analysis focus on the produced quarks via kinds of combinations
of hadrons, you see violations of NCQ scaling and this violation
increases with charge difference(\Delat q) and strangeness
difference(\Delta S).
I have no doubt about your analysis, but I want to discuss a little
about the interpretations.
Although you given a sentence in the paper draft that \Delta q and
\Delta S are inevitably correlated, but you imply the \Delta q is
the dominate effect and trying to explain it by EM-field.
When you do so, you imply the EM-field will introduce positive
\Delta v1 slope between positive charges and negative charges, while
the theoretical prediction is negative.
On another hand, our measurement shows the \Delta v1 slope between
proton and anti-proton is negative, which is qualitatively
consistent with theoretical calculations.
So there is an apparent conflict, which should be avoided and
understood before the publication.
>From my point of view, if you want to argue the positive \Delta v1
slope is introduced by EM-field(\Delta q), you should fit \Delta q
within a constant \Delta S.
Best,
Diyu
On Mar 14, 2022, at 7:42 AM, ASHIK IKBAL via Star-fcv-l
<star-fcv-l AT lists.bnl.gov> wrote:
Dear Conveners,
We would like to request for GPC of the analysis on "Electric charge
and strangeness dependent directed flow splitting of produced quarks
in Au+Au collisions".  We replied to all comments from FCV-PWG and
PWGC. There are very minor updates of the results as per the
comments from PWGC:
1. Lower pT/nq cut is shifted from 0.1 to 0.13 GeV/c to get proton
identification right.
2. Only 5 independent combinations are shown in the plot of delta-v1
slope vs charge and delta-v1 slope vs strangeness.
Here are the details of the analysis, replies and the paper draft:
1. Paper draft:

https://drupal.star.bnl.gov/STAR/system/files/v1spliting_data_paper_ver1.pdf

2. Analysis note:

https://drupal.star.bnl.gov/STAR/system/files/AN_CoalescenceQuarkFlow_ver1.pdf

3. Replies to PWGC comments:

https://drupal.star.bnl.gov/STAR/system/files/Reply_PWGCPreviewComments_Aug27_2021.pdf

4. Webpage:

https://drupal.star.bnl.gov/STAR/blog/ashik/quark-coalescence-and-directed-flow-auau-collisions

If there are no further comments/suggestions from the PWG, we wish
to request for GPC.
Thanks,
Ashik (for the PAs')
On Wed, Oct 6, 2021 at 1:25 PM ASHIK IKBAL <ashikhep AT gmail.com>
wrote:
Hi Prithwish, Shinilchi, all,
We were discussing at the FCV today about the STAR presentation
(from FCV) for the upcoming DNP21 conference and I was told to share
the agenda. Here is the information on the talks (by me, Niseem and
Chunjian) from FCV group:
Time-table: https://meetings.aps.org/Meeting/DNP21/Session/EE [1]
Room name: Park.Scollay
Zoom link: https://mit.zoom.us/my/Park.Scollay [2]
Password: MITDNP21
Best,
Ashik
On Wed, Oct 6, 2021 at 9:10 AM ASHIK IKBAL <ashikhep AT gmail.com>
wrote:
Hello all,
Please find my slides here:

https://drupal.star.bnl.gov/STAR/system/files/FCVmeeting-Oct062021-ashik.pdf

Thanks,
Ashik
On Wed, Oct 6, 2021 at 1:20 AM pdixit via Star-fcv-l
<star-fcv-l AT lists.bnl.gov> wrote:
Dear all,
I would like to give a short update on our analysis of the elliptic
and
triangular flow of multistrange hadrons in Au+Au collision at 54.4
GeV.
Please add me to the agenda.
Link to my slides:

https://drupal.star.bnl.gov/STAR/system/files/FCV_meeting_06102021.pdf

Thanks and regards,
Prabhupada
On 2021-10-04 19:22, ASHIK IKBAL via Star-fcv-l wrote:

Dear conveners,
I would like to give an update on “Coalescence and quark

flow”.

Please add me to the agenda. I will post my slides ASAP.
Thanks,
Ashik
On Mon, Oct 4, 2021 at 6:21 AM ShinIchi Esumi via Star-fcv-l
<star-fcv-l AT lists.bnl.gov> wrote:

Dear FCV PWG colleagues
We will have our weekly FCV PWG meeting on this Wednesday morning
6/Oct/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. Please prepare, if yours are not

there...

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
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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

--
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
--
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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--
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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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

--

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

Email: skradhakrishnan AT lbl.gov

--

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