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Re: [Star-fcv-l] STAR presentation by Xiaoyu Liu for DNP 2020 submitted for review

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  • From: Prithwish Tribedy <ptribedy AT rcf.rhic.bnl.gov>
  • To: "STAR Flow, Chirality and Vorticity PWG" <star-fcv-l AT lists.bnl.gov>
  • Subject: Re: [Star-fcv-l] STAR presentation by Xiaoyu Liu for DNP 2020 submitted for review
  • Date: Fri, 23 Oct 2020 19:47:38 -0400
Hello Xiaoyu,
Please consider the following comments for nice slides -- with these included I sign off.

General comment:
I wonder if it's ok to just say "v1" instead of "vn" everywhere.

slide #2:
"Extracting flow from" --> "Flow measurement using"

slide#3:
"detector consist" --> "detector that consists"
"EPD acceptance" --> "EPD acceptance (2.1<|η|<5.1)"

If you are thinking about vertex then you can write below the figure:

"EPD acceptance is 2.1<|η|<5.1 but depends on the position of collision vertex"

In order to make what you refer to as "fraction" I think you have to say
"Although the number of particles in not counted directly"
-->
"Although the number of particles hitting a tile is not counted directly"

slide #4:
"they come from physics"
-->
"they depend on incident particle distribution"

slide #4:
The line starting with "Multi-MIP peaks" is kind of repeating what is already said on this slide above -- but I leave this to you.

slide#4, figure:
I don't what's the best way to label these figures, maybe "STAR performance" or "STAR preliminary" -- I would try one of those and get suggestions from Takafumi.


slide#5:
I would start this slide by saying
"We divide η and φ-acceptance into ** and ** no of bins
respectively"

slide#5:
You have introduced Ψ1 on this slide which is not defined. You have write the details of how Ψ1 was estimated.

Add a bullet:
"We will consider the relative angle of a hit w.r.to first order event plane Ψ1 in the event"

slide#5 figure:
Add a caption: "Averaged nMIP distribution for a single η-φ bin"

slide#6 figure:
Δφ is not defined, if it is φ-Ψ1 then I would just write so or define it somewhere.

slide#6:
"to get the dN/dφ:" --> "to get:"

slide#7, the last line:
I would assume you will add more details about event plane -- there you can also mention about how event plane resolution was estimated.

slide#7, right figure:
This definitely needs more labels, like:
"Au+Au 27 GeV", "STAR Performance"

If you have confusion and you don't intend to show any data I suggest you get rid of slide#7. But then move bullet #4 to page 6 and add:
"with this v1 can be estimated by fitting Fourier decomposition"


slide#8:
"All the primary vertex (PV) are at the original point"
-->
"Primary vertex (PV) position is set to Vx,Vy,Vz=(0,0,0)"

slide#9:
please add inside all plots
"Au+Au 27 GeV, UrQMD"

slide#9:
"limit EPD resolution"
-->
"limited EPD resolution"

slide#10:
In the outlook you can add "We plan to apply this method on data and measure v1(η) at forward η"


Best,
Prithwish







On 2020-10-23 17:27, Liu, Xiaoyu via Star-fcv-l wrote:
Hello Shinichi,

Yes, it is what I did with the UrQMD + EPD Fast Simulator study as
shown in P9. It shows that the nMIP fitting method is able to count
the number of particles properly (flow measurement is essentially
counting dN/dphi).

I will consider the ADC cut in the GSTAR study, it is a very good
point and thank you for the suggestion!

If you are okay with my DNP slides, could you please sign off my talk
so it can be sent to STAR talk?

Thanks,
Xiaoyu

-------------------------

From: Star-fcv-l <star-fcv-l-bounces AT lists.bnl.gov> on behalf of
ShinIchi Esumi via Star-fcv-l <star-fcv-l AT lists.bnl.gov>
Sent: Friday, October 23, 2020 12:37 AM
To: STAR Flow, Chirality and Vorticity PWG <star-fcv-l AT lists.bnl.gov>
Subject: Re: [Star-fcv-l] STAR presentation by Xiaoyu Liu for DNP 2020
submitted for review

Dear Xiaoyu
Thank you very much for the replacement of the figures.

About the ADC cut, since you are ignoring amplitude information in the
geant
simulation just to count the number of particle per tile in the
simulation, while
you are effectively excluding pedestal noise and small ADC part below
nMip<0.3
etc in your experimental fitting method. So I just wanted to make sure
you are not
counting particle, if the ADC is quite small in your simulation, this
is to make it
as same as the experimental treatment.

Since there is no reason why not to believe the ADC distribution in
the simulation,
therefore I was thinking this would be a good test ground for your
nMip fitting to
see how well you can count the number of particle by using the ADC
distribution,
which you might have already done with the fast Epd simulator, but
this provides
the more realistic ADC distribution coming from the dE/dx and photon
statistics
with the true geometry including BG hits in the geant simulation,
where we could
even include electronics noise to make reasonable pedestal peak, if we
like to,
where we know the truth and measured ADC.

However your earlier test with UrQMD and fast simulator might include
already
the most of effects, though. Do I understand you correctly for your
fast simulator
with UrQMD, you overlay the extracted “measured” single MIP ADC
distributions
according to the number of tracks in a tile and then apply your nMip
fitting to
decompose the average number of track from the overlaid ADC
distribution using
the same single shape, which should give the same answer in principle
by
definition? This is what you are showing in p9 for your DNP talk?
Best regards, ShinIchi

On Oct 23, 2020, at 7:46, Liu, Xiaoyu <liu.6566 AT buckeyemail.osu.edu>
wrote:

Hello Shinichi,

Thanks for your suggestions. I updated my DNP slides with the new
UrQMD plots (P9: 16 variable eta bins instead of 10 even eta bins) and
the new version can be found at the same link:
https://urldefense.com/v3/__https://drupal.star.bnl.gov/STAR/presentations/dnp-2020/vn-measurement-auau-sqrtsnn-27-gev-event-plane-detector-star-1__;!!KGKeukY!iKVEEHuNtXLuV0-0rSjZyf03Az7r3Z7cvjJDVlcnem5EyFvehk9xHAI2rqgfK9PvGkwA7wVyqEjl$
[1]


For the v1 focus meeting, here is my slides:
https://urldefense.com/v3/__https://drupal.star.bnl.gov/STAR/system/files/v1_meeting_102020_0.pdf__;!!KGKeukY!iKVEEHuNtXLuV0-0rSjZyf03Az7r3Z7cvjJDVlcnem5EyFvehk9xHAI2rqgfK9PvGkwA7x0vfjo9$
[2]
If you are asking about the comparison between dN/deta of the
simulated EPD hits (blue points on P5) and the dN/deta in the EPD
acceptance extracted from the nMIP distribution with the real data,
then I don't have it but I can make one later.

I didn't use any ADC cut and I am not sure if it is needed. Even the
ADC is very small, the signal is still created by some particle
hitting the EPD tile therefore it should be counted. The small value
is just due to the Landau fluctuation.

I am not sure if I understand your last suggestion. Do you mean for
each EPD tile, I can measure the number of primary particles
(generated particles) hitting the tile and the number of "simulated
particles" (EPD hits after going through the STAR material simulation)
hitting the tile? What do you want to learn from it?

Thanks,
Xiaoyu
From: Star-fcv-l <star-fcv-l-bounces AT lists.bnl.gov> on behalf of
ShinIchi Esumi via Star-fcv-l <star-fcv-l AT lists.bnl.gov>
Sent: Wednesday, October 21, 2020 10:34 PM
To: STAR Flow, Chirality and Vorticity PWG
<star-fcv-l AT lists.bnl.gov>
Subject: Re: [Star-fcv-l] STAR presentation by Xiaoyu Liu for DNP
2020 submitted for review

Dear Xiaoyu
Thank you, that makes sense. This would mean we should not plot the
results
with too small eta bins even for the input values to be compared
with output values.
On the other hand, in the real event we do have quite a large
z-vertex variation,
so eta average of each tile in each event are different, so one
could still plot a little
finer bins in eta, if we like to, so we need to think about the
optimal size of the
eta bin. I’m fine with your nice talk for DNP.
Best regards, ShinIchi

PS : So the v1 vs eta in UrQMD and our data are quite different,
which could be
reasonable, because of the poor description of spectators. Do you
also have a
comparison of dN/deta between them?

PPS : Sorry to ask you additional questions on your another
presentation in v1
focus meeting yesterday, where you were just binary counting hits in
each tile of
EPD to get measured v1 in MC, which is indeed reasonable, but did
you exclude
hits below the value of 0.5*ADC for one mip, that need to be applied
after
integrating all hits ADC values per tile in each HI event?

Since you do have 2 ADC distributions for each tile and for both one
mip (one
particle event) and multi-mips (overlaid many single events)
including landau
and photon statistical fluctuation in addition to the real increase
of the number
of particles between the two, therefore you could also apply your
nMip fitting
method to see how well you can reconstruct the true “increase
of” average
number of particle per tile in the MC, which is a kind of good test
ground of
your approach and would also gives us the systematic error as well.
You might
need to have some constrained fitting of these two simultaneously,
where they
would have some common parameters in the function or do the fitting
of the
multi-mip data with a convoluted "data" function from the single-mip
distribution.

On Oct 22, 2020, at 1:44, Liu, Xiaoyu
<liu.6566 AT buckeyemail.osu.edu> wrote:

Hello Shinichi,

Attached are the UrQMD + EPD fast simulator study with 16 variable
eta bins (corresponding to 16 EPD rings). The black points and red
points are almost on top of each other. So the discrepancy at large
|eta| on my slide 5 is indeed due to the fact that the innermost ring
covers two eta bins.

Please let me know if you have any other suggestions or comments.

Thanks,
Xiaoyu
From: Liu, Xiaoyu <liu.6566 AT buckeyemail.osu.edu>
Sent: Sunday, October 18, 2020 8:07 PM
To: STAR Flow, Chirality and Vorticity PWG
<star-fcv-l AT lists.bnl.gov>; ShinIchi Esumi
<esumi.shinichi.gn AT u.tsukuba.ac.jp>
Subject: Re: [Star-fcv-l] STAR presentation by Xiaoyu Liu for DNP
2020 submitted for review

Hello Shinichi,

Thank you for your comments and sorry I didn't show the results at
recent BulkCorr meetings. As you mentioned, for this talk, I just want
to focus on introducing the new method and the v1, v2 plots are indeed
unnecessary for this purpose so I deleted them.

About the UrQMD study, I used the full Au+Au UrQMD events, not the
particle gun if it is what you are asking. And they are just UrQMD
events w/o going through any simulation for the STAR materials.

I believe the discrepancy in large |𝜂| is due to the fact that
the inner-most ring covers two largest 𝜂 bins therefore EPD cannot
tell exactly which 𝜂 bin the hit belongs to. So v1_EPDhit
(4.8<|𝜂 |<5.1) = v1_EPDhit (4.5<|𝜂 |<4.8) and they are all
between v1_track (4.8<|𝜂 |<5.1) and v1_track (4.5<|𝜂 |<4.8). As
for the bin 4.2<|𝜂 |<4.5, part of it falls on ring 1 and part of it
falls on ring 2 so the v1_EPDhit(4.2<|𝜂 |<4.5) will be pulled
either towards the bin on the left or the bin on the right therefore
v1_EPDhit(4.2<|𝜂 |<4.5) is smaller than v1_track (4.2<|𝜂 |<4.5)
which is the peak of v1. In other words, if I plot the same plot with
the x-axis bins being the 16 EPD rings instead of 10 even 𝜂 bins in
[2.1,5.1], the red points and the black points are expected to be on
top of each other. I can make the plot and show you later.

Sorry again for not discussing the results at BulkCorr earlier.
Hope it will be okay if I only show the UrQMD results in this talk. I
can present the UrQMD study in this week's FCV meeting if needed.

I uploaded the second version under the same link:
https://urldefense.com/v3/__https://drupal.star.bnl.gov/STAR/presentations/dnp-2020/vn-measurement-auau-sqrtsnn-27-gev-event-plane-detector-star-1__;!!KGKeukY!iKVEEHuNtXLuV0-0rSjZyf03Az7r3Z7cvjJDVlcnem5EyFvehk9xHAI2rqgfK9PvGkwA7wVyqEjl$
[1]

Please let me know if you have any other comments or suggestions.

Thanks,
Xiaoyu
From: Liu, Xiaoyu <liu.6566 AT buckeyemail.osu.edu>
Sent: Sunday, October 18, 2020 7:32 PM
To: STAR Flow, Chirality and Vorticity PWG
<star-fcv-l AT lists.bnl.gov>; ShinIchi Esumi
<esumi.shinichi.gn AT u.tsukuba.ac.jp>
Subject: Re: [Star-fcv-l] STAR presentation by Xiaoyu Liu for DNP
2020 submitted for review

Hello Jiangyong,

Thank you for your comments, I implemented most of them except:

P3: I did use a random point on the tile to determine the \eta of a
hit EPD tile.

P5: I changed the "the number of 1-, 2-, k-...MIP events per
collision" to "the fraction....". The reason why I didn't use
"probability" is that it is only the probability when we fit the
dN/dnMIP of one tile, in which case the integral of the dN/dnMIP
distribution over nMIP is 1. However, if we look at the dN/dnMIP of
several tiles then the integral of the distribution will be larger
than 1 and the sum of the 1, 2, 3, 4-MIP weights might be larger than
1 too and the word "probability" can be misleading. Then I realized
the word "number" can be equally misleading since people would expect
the number of events to be integers. Therefore, I chose "fraction" and
hopefully it is less confusing.

P9: The data points are not mirrored around y=0, they do look very
similar though.

Besides, I decided to delete the v1 before the resolution
correction with the real data as Shinichi suggested since I want to
focus on the new method and these plots are not essential for this
purpose.

I uploaded the second version to the same link:
https://urldefense.com/v3/__https://drupal.star.bnl.gov/STAR/presentations/dnp-2020/vn-measurement-auau-sqrtsnn-27-gev-event-plane-detector-star-1__;!!KGKeukY!iKVEEHuNtXLuV0-0rSjZyf03Az7r3Z7cvjJDVlcnem5EyFvehk9xHAI2rqgfK9PvGkwA7wVyqEjl$
[1]

Please let me know if you have any other comments or suggestions.

Thanks,
Xiaoyu


From: Star-fcv-l <star-fcv-l-bounces AT lists.bnl.gov> on behalf of
ShinIchi Esumi via Star-fcv-l <star-fcv-l AT lists.bnl.gov>
Sent: Saturday, October 17, 2020 11:54 PM
To: STAR Flow, Chirality and Vorticity PWG
<star-fcv-l AT lists.bnl.gov>
Subject: Re: [Star-fcv-l] STAR presentation by Xiaoyu Liu for DNP
2020 submitted for review

Dear Xiaoyu

I could sign off your nice talk, but you have not discussed this in
the
PWG yet, so it would be nice that you could have shown us before.

P7-8 : The statistical errors are invisible, but do you know why
the difference
between track(pure sim) and hit(including geant) is suddenly
increasing at
|eta|>4. Are they a strong detector effect from a large dE/dx from
spectator?
You use the true R.P. angle for both cases, is this geant
simulation done
taking a full AuAu event of UrQMD or taking a single track from the
UrQMD
event one by one?

P9-10 : Do you like your data plots to be approved as preliminary
even with
the uncorrected data? (for E.P. resolution and BG and detector
effects)
If you insist to show these, I would at least label them more
clearly that this
is uncorrected for many possible other effects, not just for R.P.
resolution)
If you like to explain your analysis methods in detail, you would
not need to
use the experimental data, but can be done more with UrQMD data. It
seems
we do see a strong spectator contributions in both v1 and v2 (and
most-likely
in dN/deta distribution as well) in data, but you can not really
defend what
this is just with uncorrected data, so I wonder what we can say
with these
plots.

Best regards, ShinIchi

On Oct 18, 2020, at 10:55, Jiangyong Jia via Star-fcv-l
<star-fcv-l AT lists.bnl.gov> wrote:

Hi, xiaoyu,

Here is my comments for sign off
cheers,
Jiangyong

P1: please add "for the STAR Collaboration" and only keep your
name

P2: For outline consider avoiding technical terms such as "nMIP"
and StEpdFastSim in

P4: I would swap the order the two sub-bullet of the nMIP

P5: Fit to extract "the probability of 1-2..k-MIP events" in bin j

P6: please indicate the AuAu 27 GeV on this figure and also other
figures where appropriate.
resolution correction --> correct for the event plane resolution

P7: StEpdFastSim--> EPD fast simulation
same format as in the STAR offline data.

a random point on the tile--> do you mean the center of the tile?

P8: ring one--> the inner-most ring
to correct for the measurement-->to account for residual detector
effects

The plots have been symmetrized around y=0, if so please indicate
that


P10: please add some statement on this slide

Plots on P8-P10 should have proper x- and y-axis labels

P11: we developed a new method



On 10/15/20 11:53 AM, webmaster--- via Star-fcv-l wrote:
Dear star-fcv-l AT lists.bnl.gov
members,

Xiaoyu Liu (
liu.6566 AT osu.edu
) has submitted a material for a review, please
have a look:


https://urldefense.com/v3/__https://drupal.star.bnl.gov/STAR/node/52381__;!!KGKeukY!iKVEEHuNtXLuV0-0rSjZyf03Az7r3Z7cvjJDVlcnem5EyFvehk9xHAI2rqgfK9PvGkwA79SUGDt9$
[3]


---
If you have any problems with the review process, please contact


webmaster AT www.star.bnl.gov

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<Picture1.pdf>

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Links:
------
[1] https://urldefense.com/v3/__https://drupal.star.bnl.gov/STAR/presentations/dnp-2020/vn-measurement-auau-sqrtsnn-27-gev-event-plane-detector-star-1__;!!KGKeukY!iKVEEHuNtXLuV0-0rSjZyf03Az7r3Z7cvjJDVlcnem5EyFvehk9xHAI2rqgfK9PvGkwA7wVyqEjl$
[2] https://urldefense.com/v3/__https://drupal.star.bnl.gov/STAR/system/files/v1_meeting_102020_0.pdf__;!!KGKeukY!iKVEEHuNtXLuV0-0rSjZyf03Az7r3Z7cvjJDVlcnem5EyFvehk9xHAI2rqgfK9PvGkwA7x0vfjo9$
[3] https://urldefense.com/v3/__https://drupal.star.bnl.gov/STAR/node/52381__;!!KGKeukY!iKVEEHuNtXLuV0-0rSjZyf03Az7r3Z7cvjJDVlcnem5EyFvehk9xHAI2rqgfK9PvGkwA79SUGDt9$
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