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Re: [Star-hp-l] Preliminary request for J/psi spin alignment measurement in Isobar data

From: subhash <subhash AT rcf.rhic.bnl.gov>
To: STAR HardProbes PWG <star-hp-l AT lists.bnl.gov>
Subject: Re: [Star-hp-l] Preliminary request for J/psi spin alignment measurement in Isobar data
Date: Thu, 21 Sep 2023 18:08:24 +0800

Dear Nihar, All,

My understanding is the results from 1st and 2nd order event plane are independent, spectator vs participant plane. If one wants to compare between the rho_00 from 1st and 2nd order EP, one need to consider the event plane de-correlation effect. You can see here: https://arxiv.org/pdf/1803.05777.pdf
My two cents.

Thanks and regards,
Subhash

On 2023-09-21 04:40 PM, Nihar Sahoo via Star-hp-l wrote:

Hello Qian,

Thank you addressing my comments. All your responses are fine to me.

One follow up on your this reply.

2.I just talking about the data, error bars can touch each other by
using "TPC 2nd order EP" and "ZDC 1st order EP".

Sorry, Not clear.

Actually, Do you have any physics expectation to the comparison if
the 1st order EP have such large error bars?

If you look at my earlier comment copied here. Probably, my earlier
comment was not clear.

2. On Slide 4, My expectation that "TPC 2nd order EP" and "ZDC 1st
order EP" may give a bit different results. But you quote "Results are
consistent with each other due to large error bars in first order
measurement". It sounds like using different Detectors ( TPC vs. EPD)
and EP order (1st vs 2nd) results are still consistent. Is that you
want to say?

What I want say is, if we use different detectors (central vs. forward
acceptance) and also different (1st vs 2nd) order EP to calculate your
J/psi spin alignment then do we expect the results would be the same
or not?
My expectation: it may not give the same because using TPC and ZDC
detector have different correlation to acceptance region. And also
different order EP could be another factor.
But you quote "Results are consistent ..."

Just to know your comment on it.

Thank you
Nihar

On 2023-09-21 13:00, tc88qy wrote:

Hello Nihar,
Please find my reply inline.

On 2023-09-20 18:16, Nihar Sahoo wrote:

Hello Qian,

Please find my reply inline.

On 2023-09-20 14:56, tc88qy wrote:

Hello Barbara and Nihar
I included 0-5% centrality to the first bin in the preliminary
request plots. The results have been updated in the preliminary
request plots. Please look at the it in this link:
https://drupal.star.bnl.gov/STAR/system/files/Preliminary_figures_request_1.pdf

Hi Nihar
1.Just as I mentioned in previous email. We should look at a
centrality range with clear physics information.

How do you know what is _clear physics_?

we probably need to think about the physics information we want to look at.
In our case, it is the charm and anti-charm correlation that affecting by QGP.
In most the Au+Au analysis, STAR paper then talk about QGP in a
centrality of 0-60% or 0-50%, just like the phi spin alignment paper
are carry out at 20-60%. 20-50% or 20-60% centrality is what people
usually look at for QGP related study.
In peripheral collision, the case could very different from central
and semi-central collision.
I think it would be good to using 0-20%, 20-50% and 50-80% centrality bins.

2.I just talking about the data, error bars can touch each other by
using "TPC 2nd order EP" and "ZDC 1st order EP".

Sorry, Not clear.

Actually, Do you have any physics expectation to the comparison if
the 1st order EP have such large error bars?

3. done
4. The rho_00 central value in 50-80% is on top of 1/3. While by
looking at the pT dependence of the same centrality,
every data points central value is above 1/3. This is
inconsistency and related to yield extraction method.
5. will done in the talk

Please include in your preliminary request also.

done

6. Please check in the preliminary request plot

Please find additional comment on your preliminary request:
https://drupal.star.bnl.gov/STAR/system/files/Preliminary_figures_request_1.pdf

1) Slide13-14: "Centrality Integral" data point, the plotting style is
incorrect because of X-axis.
I suggest to use the style of plotting in Fig.2 of Uplsilon PRL paper.
https://journals.aps.org/prl/pdf/10.1103/PhysRevLett.130.112301

This is the first time I know that we have style requirement for Physics plots.
I have update it in the same link.

2) Slide 15: "global spin alignment signal mainly from the pT range 1-3 GeV/c"
Do you mean you only use 1-3 gev/c range only for centrality
dependence plot like fig. in SLide13,14?
If so, why don't you consider 3-4 gev/c range?

In each plots, I updated it with a legend to mention the pT and y
range we used in the analysis.
And after discuss with fcv group, we decide not show the pT dependence.

3) Do you have plan to show both Fig.1 and Fig,2 outside as STAR preliminary?
I am wondering because Fig.2 shows there may be a centrality
dependence, other hand Fig.1 shows fluctuations across centralities
and also contradicts the earlier.

Yes, we plan to show both. Fig 1. just show people the signal over centralities.
In figure 2, We do not say there is a centrality dependence.
We emphasize the centrality range we selected.
0-20% with the largest J/psi regeneration probability.
20-50%, QGP with largest angle momentum or particle v2.
50-80%, a reference

Qian Yang

Thank you
Nihar

Regards,
Qian Yang

On 2023-09-20 15:51, Nihar Sahoo wrote:

Hello Qian,

My apologies, for my late response.
Please find my comments on your preliminary request.

1. On Slide3 "Centrality binning", I would prefer to use 0-20%,
20-40%, and 40-80% binning. Let me know what do you think. As is done
in Slide4 right side figure with STAR preliminary.
2. On Slide 4, My expectation that "TPC 2nd order EP" and "ZDC 1st
order EP" may give a bit different results. But you quote "Results are
consistent with each other due to large error bars in first order
measurement". It sounds like using different Detectors ( TPC vs. EPD)
and EP order (1st vs 2nd) results are still consistent. Is that you
want to say?
3. Slide5 left fig: I think you need to include 0-20% instead of 5-20%
centrality for pT-dependence plot. Is not it? [same for Slide7]
4. Slide5: "ρ00 systematic above 1/3 in pT dependence study for
50-80%…" -> But it looks all are consistent with 1/3 (dotted line)
within uncertainty except 2-3 GeV/c pT bin (just ~1 sigma difference).
Is not that?
5. SLide8: Please Include ALICE reference.
6. Please include also Physics message/conclusion on Slide 6,7,8.

Thank you
Nihar

On 2023-09-20 11:39, Barbara Trzeciak via Star-hp-l wrote:

Hi Qian,

I don't have strong preference about the 40, 50 or 60%, you can leave
it as you had, 20-50 and 50-80%.
The main point was about not excluding the 0-5% range.
So from my side it's fine. But please wait if conveners have any
comments on this.

Cheers,
Barbara

On Wed, 20 Sept 2023, 07:55 tc88qy, <tc88qy AT rcf.rhic.bnl.gov> wrote:

Hi Barbara,

The last centrality bin will have large error bar as shown in my
binning study.
What about 50-80%, it will reduce the error bars.
I also checked the 50-80% <N_part> in Isobar, it is comparable
with
60-80% <N_part> in Au+Au.

Qian Yang

On 2023-09-20 12:51, Barbara Trzeciak wrote:

Hi Qian,
that's also fine. My only worry is that you will have large
uncertainty for the pT different rho00 in this bin. But you can

check.

Cheers,
Barbara

On Wed, 20 Sept 2023, 05:39 tc88qy, <tc88qy AT rcf.rhic.bnl.gov>

wrote:

Hi Barbara,
I see your point. I agree to include 0-5% centrality to the
first
bin.
If we do 20-40% and 40-80% centrality, the last bin do gain
precisions.
But we probably need to think about the physics information we

want

to
look at. In our case, it is the charm and anti-charm correlation
that
affecting by QGP. In most the Au+Au analysis, STAR paper then

talk

about
QGP in a centrality of 0-60%, just like the phi spin alignment

paper

are
carry out at 20-60%.
So, I suggest we do the binning of 0-20% , 20-60% and 60-80%.
What do you think?

Qian Yang

On 2023-09-19 23:39, Barbara Trzeciak wrote:

Hi Qian,

thanks for point to the slides with additional checks.
Regarding 0-5% centrality bin:
As ShinIch also commented, sometimes the most central bin is

remove

due to poor event plane resolution. However, in this case I

don't

see

the resolution being particularly bad, it's not so much worse

than

for

the mid-central case. If we have enough confidence to have this
point

in the centrality differential plot, I don't see a reason why

not

to

include it when you integrate to wider centrality ranges.
Regarding the other binning:
The reason for having 20-40% and 40-80% is that the precision of
the

mid-central point is almost the same while the peripheral bin

gains in

precision compare to the 50-80% centrality range.

Cheers,
Barbara

On Tue, 19 Sept 2023, 17:21 tc88qy, <tc88qy AT rcf.rhic.bnl.gov>

wrote:

Hi Barbara,

I replied to the HP list for the comments I got from last HP
meeting.
Please find the details in this link:

https://drupal.star.bnl.gov/STAR/system/files/jpsiSpinAlignment_20230917.pdf

In terms of the binning, I am not sure the reason of 20-40%

bin.

Qian Yang

On 2023-09-19 22:15, Barbara Trzeciak wrote:

Hi Qian,

I see that you consider three centrality classes on plots on

slides

14-16 - same as you presented last week.
As we discussed in more detail at the previous HP meeting, it
looks a

bit weird (and I don't know what's the motivation in this

case)

that

you exclude 0-5% centrality bin.
I suggest having the first bin as 0-20% centrality, then

20-40%

and

40-80%.
Also, could you please prepare a comparison to the results

that

use

the first order event plane.

Cheers,
Barbara

On Mon, Sep 18, 2023 at 10:36 AM tc88qy via Star-hp-l
<star-hp-l AT lists.bnl.gov> wrote:

Hello all,
Please find my preliminary plots request in link below:

https://drupal.star.bnl.gov/STAR/system/files/Preliminary_figures_request_1.pdf

Qian Yang
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Re: [Star-hp-l] Preliminary request for J/psi spin alignment measurement in Isobar data , (continued)