STAR Flow, Chirality and Vorticity PWG

[haojiexu <haojiexu AT rcf.rhic.bnl.gov>]

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_v11.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_HaojieXu_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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