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Re: [Star-fcv-l] STAR presentation by Haojie Xu for Quark Matter 2022 submitted for review

From: haojiexu <haojiexu AT rcf.rhic.bnl.gov>
To: "Wang, Fuqiang" <fqwang AT purdue.edu>, "STAR Flow, Chirality and Vorticity PWG" <star-fcv-l AT lists.bnl.gov>
Subject: Re: [Star-fcv-l] STAR presentation by Haojie Xu for Quark Matter 2022 submitted for review
Date: Mon, 25 Apr 2022 07:03:04 +0800

Dear ShinIchi, Huan, Jie, and all,

Thank you for the suggestions. The comparison between two different run periods is shown on page 3 of the attached file. The correlation in RuRu collision is just a coincidence, as we do not see any obvious correlations for the rest of the runs.

The second page is for run-by-run distributions. I also made a plot for e-by-e distributions on page 4. As I have mentioned in the last FCV meeting, these distributions are due to the multiplicity-dependent vertex resolutions.

Therefore, as mentioned by Fuqiang, we can not re-weight or cut events at the event level due to resolutions. I then apply the cut on run level, i.e., divide the events into two groups by run-by-run mean vx and vy, the results are shown on page 5. The distributions are almost the same in two different <vx> and <vy> groups, which confirm that no efficiency difference over vx, vy variations on this level.

The mean multiplicity difference between Ru+Ru and ZrZr is about 0.2% in the high multiplicity range, as I have shown in my QM talk. One bin shift will cause ~0.16% differences in the mean multiplicity ratio. To achieve our goal on determine the slope parameter of symmetry energy, if any effect causes a difference above ~0.02%, I will consider such effect seriously. The effect shown on page 5 is only about ~0.002%, negligible in our measurements.

Yes, the shape differences are very important in our study and very sensitive at high multiplicity range. That’s the reason we put more effort into the refined centrality in isobar collisions. We found the shape corrections from previous official centrality definition are quite large, which will cause large sys uncertainties in our study. We then improved vz corrections and now such uncertainty is negligibly small. I think this may answer Huan’s question about the efficiency effect on multiplicity distribution shape at the very tail region, as the efficiency do have vz dependent but only affects the high-end-point value. Here are my slides from the last collaboration meeting for your reference

https://drupal.star.bnl.gov/STAR/system/files/FCV20220216.pdf

Again, thank you for the suggestions.

With best regards,
Haojie

On 2022-04-24 00:39, Wang, Fuqiang via Star-fcv-l wrote:

Hi, Huan, Jie,

Yes, cutting or reweighting events will be biasing the events.
Haojie’s highend point multiplicity vs Vx, Vy already showed that.
The vx vy distributions are mainly due to the vertex position
resolutions therefore dependent on event multiplicity. Cutting on them
is cutting on resolution. One cannot apply cuts or selection on event
level, but only on runs or run periods.

Best regards,
Fuqiang

On Apr 23, 2022, at 3:02 AM, Huan Zhong Huang via Star-fcv-l
<star-fcv-l AT lists.bnl.gov> wrote:

Hi Jie,

That is an interesting idea. I do not know enough about beam
physics to have a firm answer. I assume that the actual beam size is
much smaller than the measured Vx and Vy distributions, but the
center value should be correct beam position. Therefore, the
measured Vx, Vy width may be mostly due to track resolutions. Then
if you only take events on one side of the resolution function in
order to match the RuRu and ZrZr distributions, I do not know if it
will introduce any bias.

Regards,

Huan

From: Jie Zhao <jiezhao1119 AT hotmail.com>
Sent: Friday, April 22, 2022 5:21 PM
To: Huan Zhong Huang <huang AT physics.ucla.edu>; STAR Flow, Chirality
and Vorticity PWG <star-fcv-l AT lists.bnl.gov>
Cc: ShinIchi Esumi <esumi.shinichi.gn AT u.tsukuba.ac.jp>
Subject: Re: [Star-fcv-l] STAR presentation by Haojie Xu for Quark
Matter 2022 submitted for review

Dear Huan, ShinIchi, Haojie,

i am wondering, whether a data driven method would be helpful or
not, for example,

artificially weight or throw away part of the RuRu data to match the
ZrZr vx/vy/vz distribution,

and see how big the difference?

Best regards,

Jie

On Apr 23, 2022, at 3:56 AM, Huan Zhong Huang via Star-fcv-l
<star-fcv-l AT lists.bnl.gov> wrote:

Dear Haojie and ShinIchi,
Thanks for the update and sorry for the late response. It is very
typical nowadays that I lag behind in my email responses.
On a gross scale, I do not have any problem if you claim that there
is no effect related to vertex and/or efficiency differences. But
when you focus on the ratio at the very tail region, we know that
the sensitivity is very much enhanced. So I have not seen any
quantitative estimate that demonstrated that there is nothing to
worry about.
When you examine the multiplicity and the vertex positions to see
if there is any correlations, you did it as a function of run
number. I am afraid that this approach may not be a sensitive way.
As you may know the vertex position averaged over a run contains too
many effects including the z vertex and the slope parameters which
may be run dependent. You may be better off to focus on data within
one run. I understand that you have already done the Vz dependent
corrections. So you may ask the question whether you correctly
attributed the physical reason for the Vz correction and whether the
correction method (for the turning point, instead of the falling
shape for example) is well justified.
When I suggested you to carry out quantitative systematic estimate,
it probably does not make sense to you. Let me try to elaborate a
little. Since you focus on the ratio of multiplicity in the tail
region, you may check how the ratio changes with possible
multiplicity shift (more detailed and finer steps than Yu did). Then
if you decide that in order to constrain nuclear shape parameters
well using the ratios in the tail region, you may decide our goal of
systematic error allowed. That would be our quantitative goal for
controlling the systematics for this physics measurement.
Once you know the goal that you need to achieve, you may be able to
examine if your Vz/Vx/Vy studies are compatible with achieving the
goal. We know that the average multiplicity between Ru+Ru and Zr+Zr
differ by a few counts while the average Vx and Vy are slightly
different. I wondered that among these two refmult difference how
much should be attributed to true shape difference and how much to
run condition difference. What makes you so confident that there is
no effect from vertex difference at the accuracy level that we need
to achieve. If we trust the simulation package, we may have to
simulate the same collisions with a slight shift in vertex positions
in order to guage the sensitivity.
In any case, thanks for the hard work.
Regards,
Huan

-----Original Message-----
From: Star-fcv-l <star-fcv-l-bounces AT lists.bnl.gov> On Behalf Of
ShinIchi Esumi via Star-fcv-l
Sent: Thursday, April 21, 2022 8:58 PM
To: STAR Flow, Chirality and Vorticity PWG
<star-fcv-l AT lists.bnl.gov>
Subject: Re: [Star-fcv-l] STAR presentation by Haojie Xu for Quark
Matter 2022 submitted for review

Dear Haojie
Thanks for the plots. I have one question.
Is the second page for the entire run and event for both RuRu and
ZrZr?
Could you plot the 2nd page correlation just for the two run ranges
for each of 2 species, where you draw 2 black lines (run ranges) in
each panel of the 1st page, and plot one range for red and another
range for blue points?
Could you also plot each point event-by-event, not run-by-run for
these two run ranges.
Best regards, ShinIchi

On Apr 22, 2022, at 10:33, haojiexu <haojiexu AT rcf.rhic.bnl.gov>
wrote:

Dear ShinIchi, Huan, and all,

Under Jiangyong's suggestion, I have plotted the run-by-run vertex
distributions in both Ru+Ru and Zr+Zr collisions, attached please
find the plots. The vertex variations in each system are larger than
the average difference between the two systems. I also plot the
<RefMult> vs <vx>, <vy> and <vr> in each collision system. There is
no evidence of efficiency difference over vx, vy variations on this
level.

with best regards,
Haojie

On 2022-04-21 20:49, ShinIchi Esumi via Star-fcv-l wrote:

Dear Huan and all
There were some interesting discussions about this in the PWG
meeting
yesterday, the results presented by Haojie in the meeting were not
enough to fully answer your question (you can see his slide in the
usual PWG agenda page at :
https://drupal.star.bnl.gov/STAR/blog/jjiastar/bulkcorr). One
difficulty is the vertex resolution changes with centrality (track
multiplicity in the tpc), but there were few more suggestions made
during the meeting, so let’s see his future updates. Do we just
worry
about the actual vertex position dependence of the tpc efficiency?,
which is basically the homework for Haojie to see the vertex
position
(3D xyz vertex) dependence of efficiency (effectively number of
reconstructed track for a given acceptance), Or do we also need to
worry about beam tuning/focusing differences, for example, beam
crossing angle difference etc between the species?
One thing I forgot to ask yesterday was about the simulation test,
where we used say our accuracy of tracking efficiency is of the
order
of 5% for the systematic error evaluation in the absolute yield
measurements, which is clearly not enough for these studies, so the
most of the people seem to be given up in this direction, but I
remember there were some task force formed sometime ago, to revisit
our accuracy of 5% on the absolute efficiency in the tpc, and to see

if we can improve this or not. We need to see if there is any
progress in this direction or not, too… Best regards, ShinIchi

On Apr 15, 2022, at 11:42, Huan Zhong Huang <huang AT physics.ucla.edu>
wrote:
Hi ShinIchi and Haojie,
Thanks for the discussion. To pursue the physics topic, we need to
demonstrate that we have done the systematic study to the accuracy
of much better than 1/(300-400) in multiplicity measurement. We may
have done lots of systematic studies, but I am not aware one which
showed the accuracy matched what is needed for this physics topic.
It will be useful to keep this requirement in mind when you consider
more studies. It would certainly be very useful to have a full geant
simulation of Ru collisions with realistic beam profile and with the
correct magnitude of position shifts to see any effect.
Haojie: if you think that your previous results have the accuracy
needed, please summarize your results/arguments in a few slides to
circulate. In particular, we will be interested in why you think
that you have the quantitative accuracy of 1/(300-400).
Thanks. Regards,
Huan
-----Original Message-----
From: Star-fcv-l <star-fcv-l-bounces AT lists.bnl.gov> On Behalf Of
ShinIchi Esumi via Star-fcv-l
Sent: Wednesday, April 13, 2022 7:50 PM
To: STAR Flow, Chirality and Vorticity PWG
<star-fcv-l AT lists.bnl.gov>
Subject: Re: [Star-fcv-l] STAR presentation by Haojie Xu for Quark
Matter 2022 submitted for review Dear Haojie Thank you for the
confirmation. The question is how accurately we do know the relative
efficiency difference between species, compared to the observed
level of multiplicity difference of ~1/(a few 100). TPC condition
itself is unchanged as we filled two beams alternatively, but the
beam optics/position seems to be different. The effect coming from
less than mm difference of beam using the meter size detector would
be small, but we just need to make sure the effect is at lease much
smaller than ~1/(a few 100) in the realistic experimental condition.
Best regards, ShinIchi

On Apr 14, 2022, at 11:35, haojiexu <haojiexu AT rcf.rhic.bnl.gov>
wrote:
Dear ShinIchi,
The efficiency corrections are not implemented yet. As we have
discussed during my presentation, we plan to use the same
efficiency for two isobar systems, as the accuracy may not be good
enough to do it separately.
with best regards,
Haojie
On 2022-04-14 09:29, ShinIchi Esumi via Star-fcv-l wrote:

Dear Haojie and all
I think Huan has a point, if the tracking efficiency is really
different between the two species caused by the small beam shift
(or any beam related systematic difference), the beam luminosity
and/or zvertex corrections for the refmult would not correct such
difference, since
“97 vs 98” difference remain unchanged after the corrections and

this difference of “1 out of 500” that we believe that it is
coming from the nuclear structure, but I‘m not sure we have ruled
out any small fraction of “1” that might be coming from the beam

systematics or not.
Do we correct for the tracking efficiency (for the refmult)
independently between two species?
This might be a question of accuracy of our embedding simulation,
that does use the real data, but how precisely we can reproduce
the beam quality/position difference for the embedded track to be
combined into the real events for each species independently. Or
we might need to test this with full geant simulation with
realistic beam optics/profile, to see if our TPC (with realistic
holes of inactive RDOs etc) is sensitive to this or not. This is
to ask ourselves, if we already know our TPC efficiency (better
than ~1/500) relatively between two species, that is being
questioned.
Best regards, ShinIchi

2022/04/14 9:41、haojiexu via Star-fcv-l
<star-fcv-l AT lists.bnl.gov>
のメール：
Hi Huan,
Thank you for your comments and interest in my QM talk. And also
thank Yu for the testing on multiplicity shift, the effect of one
bin offset is large but I don’t think this shift is reliable.
The multiplicity ratios shown in my QM slides are not the raw
multiplicity distributions. As it was done in the general centrality
definition procedure, we have corrected the luminosity dependent and
the multiplicity distributions in different vz bins are corrected to
vz=0. I think the effect you mentioned has been taken care of by the
procedures. More details of the procedure can be found in my
presentation given in the centrality definition meeting:
https://drupal.star.bnl.gov/STAR/system/files/Centrality20220301.
pdf Yes, the neutron skin effect can also be obvious at
peripheral collisions. One of the observables is the net charge
ratios I have shown in my QM presentation.
with best regards,
Haojie
On 2022-04-12 03:19, Huan Zhong Huang wrote:

Hi Haojie et al,
This is an interesting approach. I am concerned whether you have
done the systematic checks to demonstrate the sensitivity of
potential systematic bias to the physics conclusion. Yu Hu
helped to plot the multiplicity ratio of Ru+Ru/Zr+Zr if the
multiplicity of the Zr+Zr collisions is systematically offset by a
few tracks.
When the Zr multiplicity is shifted by one track out of 300-400
tracks, the ratio changes very significantly. Therefore, it is
critical that we show that there is no systematic bias between
two isobar collisions even at one particle level.
Because of the isobar charge difference, I tried to ask CAD what
the possible magnitude of beam difference (position and collision
axis).
Bill Christie suggested that we should be able to get the data
from reconstructed vertex distributions as a function of Z. Gene
Van Buren has some data on this. He indicated that the beam
position between Ru and Zr could be shifted by 40-50 microns. We
may need to examine this shift with the full isobar data. In
order to examine if this magnitude of beam shift will cause any
systematic bias in the measured multiplicity, we may need to use
GEANT simulations of the Ru+Ru collisions and shift the beam
position to measure potential change in the TPC multiplicity.
That would ensure that we have a good control of the
systematics. There may be other approaches to use experimental
data to examine the potential shift due to beam variations. But
I do not know how well we can control the systematics with the
experimental approach.
If this potential systematic shift is real, we may have to
revisit the model used for centrality definition as well.
Naively I would expect that the peripheral collisions would be
more sensitive to the shape and distribution of the neutron skin.
In any case, this is an interesting topic. It would be good if
you help evaluate these sensitivity issues. I am sorry that it
took me long to catch up with many interesting QM talks and did
not comment sooner.
Thanks. Regards,
Huan
-----Original Message-----
From: Star-fcv-l <star-fcv-l-bounces AT lists.bnl.gov> On Behalf Of
haojiexu via Star-fcv-l
Sent: Wednesday, March 30, 2022 10:39 AM
To: Chunjian Zhang <chun-jian.zhang AT stonybrook.edu>
Cc: STAR Flow, Chirality and Vorticity PWG
<star-fcv-l AT lists.bnl.gov>
Subject: Re: [Star-fcv-l] STAR presentation by Haojie Xu for
Quark Matter 2022 submitted for review Dear Chujian, Rongrong,
and all, Slide 12 has been updated with chunjian's new plot.
Comments from google doc are also implemented. Here is the link
to the updated slides
https://drupal.star.bnl.gov/STAR/system/files/QM2022_HaojieXu_v1
1.p
df
with best regards,
Haojie
On 2022-03-30 09:52, Chunjian Zhang wrote:

Dear Haojie,
Hello. It’s a very nice result from hydro and I am looking
forward to your nice draft. Thank you~ best regards Chunjian

On Mar 29, 2022, at 8:46 PM, haojiexu
<haojiexu AT rcf.rhic.bnl.gov>
wrote:
Dear Chunjian,
Thank you for considering my suggestion. Actually, our
hydrodynamics give the same conclusion that the two system
have the same nonlinear coefficients within error, while the
approximation can bias this conclusion. It is good to hear that the
data show the same trend.
It is interesting that the magnitude of this bias can be
quantitively described by our hydrodynamic simulaitons, this
may indicate the non-flow contributions are largely canceled
in the ratios. Attached please find plot from our recent work
that we plan to submit to arXiv in the next few days.
with best regards,
Haojie
On 2022-03-30 07:50, Chunjian Zhang wrote:

Dear Haojie,
Hello. Very nice and comprehensive slides to me.
Thank you for your nice suggestions. Now we use the exact
ac2{3}/<v_2^4> ratio between Ru+Ru and Zr+Zr collisions as
the equations.
Please find the new plot in
https://drupal.star.bnl.gov/STAR/system/files/ac23_STAR_0329.
pdf It will be helpful if you could use this new plot to
replace the old version in the slide 12. And also change the
third bullet point to “Non-linear coefficents are ideally
identical in the final-state””.
Thank you.
The nonflow would be mostly canceled and then will not affect
the double ratios in the lower panel especially from
midcentral to central collisions. If it still has residual
nonflow, it may only affect peripheral region a little bit.
The model study here also helps us to clarify this. Even so,
the futher relevant nonflow understanding is ongoing in our to do
list.
best regards
chunjian

On Mar 29, 2022, at 1:07 AM, haojiexu
<haojiexu AT rcf.rhic.bnl.gov> wrote Hi Chunjian, and all Your
nice suggestions are implemented, here is the updated slides

https://drupal.star.bnl.gov/STAR/system/files/QM2022_HaojieXu
_v1
0.pd
f

I am still worried about the message from lower panel of ac3 plot.
Besides the non-flow effect, as I have already mentioned,
the ac2{3}/v_2{2}^{4} is not exactly the non-linear coefficient.
As it was just an approximation, I suggest not to extract
any nonlinear coefficient at this moment. Or can you
directly compare ac2{3} to <v_2^{4}> instead of v_2{2}^{4}?
with best regards,
Haojie
On 2022-03-29 04:56, Chunjian Zhang wrote:
Dear Haojie,
Hello. Very nice and comprehensive slides. Please find some
comments
below:
1) S3:
—> v2-> v_{2}
—> I guess you would like to use the new Ntrk ratio plot
from the nice isobar publication.
2) S9: It would be helpful if you could add one more reference:
J.Jia
and C. Zhang, arXiv:2111.15559
4) S12:
—> above formula, n=2, just label ac_2{3}….
—> I would be helpful you could add a punchline as other
slides at
below: “Experimental test on non-linear coupling coefficient”.
Thank you for your suggestions for the plots. The double
ratio is the money plot calculated from above panels. Then
the audiences would see how is the difference directly.
Also, ampt calculation could reproduce the data. The
detailed nonflow studies for understanding any flow
observables are extramly complicated and there are no any conclusive
answers yet. let’s not worry about it.
best regards
Chunjian
On Mar 28, 2022, at 11:22 AM, haojiexu via Star-fcv-l
<star-fcv-l AT lists.bnl.gov> wrote:
Dear chunjian, and all
The slides have been updated with suggestions from the last
FCV meeting and Collaboration meeting. I also made a few minor
changes.
Your comments are welcome. Here is the link to my slides
https://drupal.star.bnl.gov/STAR/system/files/QM2022_HaojieX
u_v 9.pd f I have a suggestion on ac2{3} plot in slide 12. I
suggest do not show the lower panel and the value of the
non-linear coefficient ratio, because the ac2{3}/v_2{2}^{4}
is not exactly the non-linear coefficient, and ac2{3} is
also sensitive to non-flow effect.
with best regards,
Haojie
On 2022-03-08 23:55, webmaster--- via Star-fcv-l wrote:
Dear star-fcv-l AT lists.bnl.gov members, Haojie Xu
(haojiexu AT zjhu.edu.cn) has submitted a material for a
review, please have a look:
https://drupal.star.bnl.gov/STAR/node/58778
---
If you have any problems with the review process, please
contact webmaster AT www.star.bnl.gov
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Re: [Star-fcv-l] STAR presentation by Haojie Xu for Quark Matter 2022 submitted for review , (continued)