STAR Flow, Chirality and Vorticity PWG

[Prithwish Tribedy <ptribedy AT rcf.rhic.bnl.gov>]

Hi Jiangyong, Chunjian,

>  I do not see it is a problem, as long as we add a descriptor, e.g.
> name it as normalized skewness (via k_1) then there is no confusion.

That would be good. We should do that on slide#8, how about:
"Normalized third central moment \proporto skewness"

And on conclusion slide#:
"enhancement in variance and skewness ratios" --> "enhancement in 
variance and third order fluctuation ratios"

Best,
Prithwish




On 2022-10-25 12:13, Jiangyong Jia via Star-fcv-l wrote:
> Hi, Prithwish,
>
> The "official" definition of skewness is as what you say.
>
> According to wikipedia, there are many other Pearson definition of
> skewness with different nomralization (mode skewness, median
> skewness). Then we also have "intensive skewness" <(\delta
> N)^3>*<N>/sigma^2 defined in a recent paper.
>
> <(\delta N)^3> is can be called third central moment or moment
> coefficient of skewness.
>
>  I do not see it is a problem, as long as we add a descriptor, e.g.
> name it as normalized skewness (via k_1) then there is no confusion.
>
> Cheers,
>
> Jiangyong
>
> On 10/25/22 11:57 AM, Prithwish Tribedy via Star-fcv-l wrote:
>
> > Dear Chunjian,
> > What you have written is not correct. In STAR we have been
> > studying Skewness of distributions for more than a decade. See for
> > example:
> >
> > https://arxiv.org/pdf/1004.4959.pdf [1]
> > https://arxiv.org/pdf/1309.5681.pdf [2]
> > https://arxiv.org/pdf/2001.02852.pdf [3]
> > https://arxiv.org/pdf/2101.12413.pdf [4]
> >
> > Skewness = <(\delta N)^3>/\sigma^3 (where, \delta N = N-<N> & \sigma
> > is the square root of variance)
> > What you have is <(\delta N)^3>/<N>^3, they are not the same.
> >
> > Again, note that the quantity you have is related to Skewness but
> > should be called scaled third order central moment and NOT Skewness.
> > (Also, note the difference between moment & central moment here.)
> >
> > Where did you find this definition of Skewness? Is it from one of
> > the method papers? Do you have a link?
> >
> > Best,
> > Prithwish
> >
> > On 2022-10-24 15:01, ChunJian Zhang wrote:
> > Dear Prithwish,
> >
> > Thank you for the comments. Skewness is <(\delta p_T)^3> which is
> > also
> > can be called moments since they are the same when one does it from
> > mean, variance to skewness. Note that kurtosis defined as <(\delta
> > p_T)^4> - 3<(\delta p_T)^2> is different from the moments.
> >
> > Others like <(\delta p_T)^3>/<p_T>^3  and <(\delta p_T)^3>/<(\delta
> > p_T)^2>^3/2 are different normalization ways.
> >
> > So, here we call <(\delta p_T)^3> as skewness is appropriate.
> >
> > Best regards
> > Chunjian
> >
> > On Oct 24, 2022, at 11:53 AM, Prithwish Tribedy via Star-fcv-l
> > <star-fcv-l AT lists.bnl.gov> wrote:
> >
> > Dear Chunjian,
> > Thanks for incorporating my comments. Please note that the quantity
> > you are showing on slide#8 (lower right plot) is the ratio of
> > <(\delta p_T)^3>/<p_T>^3 -- this quantity is not Skewness.
> >
> > In terms of your notations "Skewness" will be something like:
> > "<(\delta p_T)^3>/<(\delta p_T)^2>^3/2. Since you're not plotting
> > that so we should not be calling it Skewness.
> >
> > I think we should refer the quantity <(\delta p_T)^3>/<p_T>^3 as
> > "Scaled third order moment" or "Normalized third order moment".
> >
> > On conclusion slide we can say:
> > "enhancement in variance and skewness ratios" --> "enhancement in
> > variance and third order fluctuation ratios"
> >
> > Best,
> > Prithwish
> >
> > On 2022-10-24 09:50, ChunJian Zhang wrote:
> > Dear Prithwish,
> > Thank you for the helpful comments. With including all the
> > suggestions, please find the new version at
> https://drupal.star.bnl.gov/STAR/presentations/DNP-2022/Measurement-nuclear-deformation-high-energy-isobaric-96Ru96Ru-and-96Zr96Zr--0
> > Please find the comments included and addressed as follows:
> > Side#3:
> > Define "0\nu\beta\beta" somewhere on this slide.
> > "Rarely experimental measurements" --> "Few experimental
> > measurements" or "Rarely explored in experiment”
> > Changed
> > Slide#4: "based on N_{ch}^{offline} with" --> "based on uncorrected
> > tracks (N_{ch}^{offline}) in”
> > Changed
> > Slide#6: Some texts are overlapping, the page number is hidden.
> > Changed
> > Miner & optional comment: the references are not written in
> > conventional  formats (like Zhang and Jia, PRL 128, 022301 (2022)).
> > Changed
> > "cancelation" --> "cancellation"
> > Changed
> > It is not clear what you mean by "cancellation expected in
> > non-central collisions". What gets cancelled with what? Also, this
> > is approximately true, right ? Then maybe say "approximate
> > cancellation”
> > Added “approximate". The effect from Beta_3 canceled the v2
> > ratios.
> > The 4th bullet is a bit confusing, right? What do you mean by this?
> > It depends on how the size is defined. Larger neutron skin means
> > large size, so there's an apparent contradiction between the 3rd and
> >
> > the 4th bullets.
> > added "R0"
> > Slide#7:
> > "non-linear" --> "Nonlinear" in title and everywhere
> > Changed
> > "reflect nuclear structure" --> "reflects difference in nuclear
> > structure”
> > Changed
> > It's impossible to see what you're plotting on the two right
> > figures. At least write in bigger fonts that you're plotting "Mean
> > ratio" and "Third moment ratio”
> > Add large labels
> > Slide#8: "Study nuclear structure" --> "Study of nuclear structure"
> > "increase in central" --> "increase in central collisions"
> > Changed
> > It is very difficult to read what is plotted on the
> > Add large labels
> > Slide#9: Add "More investigation using STAR data is underway”
> > Added
> > It is not clear what your conclusion is from the data-model
> > comparison on the right. Can you please add a short sentence.
> > Add one more sentence.
> > Slide#10: "identical for Ru and Zr in final state as expected" -->
> > "consistent between Ru+Ru and Zr+Zr as expected"
> > While talking do mention that "as is it driven by final state
> > effects”
> > Changed and will follow your nice suggestions.
> > "variance and skewness" --> You didn't show skewness, maybe say
> > "variance and third order moment”
> > We showed the skewness  in the right lower plot on slide 8th
> > Add "more studies underway" in the last bullet.
> > Added
> > Best regards
> > Chunjian
> > On Oct 23, 2022, at 6:43 PM, Prithwish Tribedy via Star-fcv-l
> > <star-fcv-l AT lists.bnl.gov> wrote:
> > Dear ChunJian,
> > Very nice slides. Here are my comments. With these included, I sign
> > off.
> > General comment: some of the fonts you have used are too small.
> > Side#3:
> > Define "0\nu\beta\beta" somewhere on this slide.
> > "Rarely experimental measurements" --> "Few experimental
> > measurements" or "Rarely explored in experiment"
> > Slide#4: "based on N_{ch}^{offline} with" --> "based on uncorrected
> > tracks (N_{ch}^{offline}) in"
> > Slide#6: Some texts are overlapping, the page number is hidden.
> > Minor & optional comment: the references are not written in
> > conventional  formats (like Zhang and Jia, PRL 128, 022301 (2022)).
> > "cancelation" --> "cancellation"
> > It is not clear what you mean by "cancellation expected in
> > non-central collisions". What gets cancelled with what? Also, this
> > is approximately true, right ? Then maybe say "approximate
> > cancellation"
> > The 4th bullet is a bit confusing, right? What do you mean by this?
> > It depends on how the size is defined. Larger neutron skin means
> > large size, so there's an apparent contradiction between the 3rd and
> >
> > the 4th bullets.
> > Slide#7:
> > "non-linear" --> "Nonlinear" in title and everywhere
> > "reflect nuclear structure" --> "reflects difference in nuclear
> > structure"
> > It's impossible to see what you're plotting on the two right
> > figures. At least write in bigger fonts that you're plotting "Mean
> > ratio" and "Third moment ratio"
> > Slide#8: "Study nuclear structure" --> "Study of nuclear structure"
> > "increase in central" --> "increase in central collisions"
> > It is very difficult to read what is plotted on the
> > Slide#9: Add "More investigation using STAR data is underway"
> > It is not clear what your conclusion is from the data-model
> > comparison on the right. Can you please add a short sentence.
> > Slide#10: "identical for Ru and Zr in final state as expected" -->
> > "consistent between Ru+Ru and Zr+Zr as expected"
> > While talking do mention that "as is it driven by final state
> > effects"
> > "variance and skewness" --> You didn't show skewness, maybe say
> > "variance and third order moment"
> > Add "more studies underway" in the last bullet.
> > Best,
> > Pritwish
> > On 2022-10-14 15:41, webmaster--- via Star-fcv-l wrote:
> > Dear star-fcv-l AT lists.bnl.gov members,
> > ChunJian Zhang (chun-jian.zhang AT stonybrook.edu) has submitted a
> > material for
> > a review, please have a look:
> > https://drupal.star.bnl.gov/STAR/node/61340
> > Deadline: 2022-10-27
> > ---
> > If you have any problems with the review process, please contact
> > webmaster AT www.star.bnl.gov
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>
>
> Links:
> ------
> [1] 
> https://urldefense.com/v3/__https://arxiv.org/pdf/1004.4959.pdf__;!!P4SdNyxKAPE!HbmYLU7v5YzARF2J8-Q6C3VJDU6fBF9L2E9P4qD3Gv2v9IiNJQFRDeqj5gcA9AkwXI_gz7tbqAbJby43uaQ_IIDCfXl8dmJnm4RiBB4$
> [2] 
> https://urldefense.com/v3/__https://arxiv.org/pdf/1309.5681.pdf__;!!P4SdNyxKAPE!HbmYLU7v5YzARF2J8-Q6C3VJDU6fBF9L2E9P4qD3Gv2v9IiNJQFRDeqj5gcA9AkwXI_gz7tbqAbJby43uaQ_IIDCfXl8dmJnpVSTeSM$
> [3] 
> https://urldefense.com/v3/__https://arxiv.org/pdf/2001.02852.pdf__;!!P4SdNyxKAPE!HbmYLU7v5YzARF2J8-Q6C3VJDU6fBF9L2E9P4qD3Gv2v9IiNJQFRDeqj5gcA9AkwXI_gz7tbqAbJby43uaQ_IIDCfXl8dmJn91NpyLk$
> [4] 
> https://urldefense.com/v3/__https://arxiv.org/pdf/2101.12413.pdf__;!!P4SdNyxKAPE!HbmYLU7v5YzARF2J8-Q6C3VJDU6fBF9L2E9P4qD3Gv2v9IiNJQFRDeqj5gcA9AkwXI_gz7tbqAbJby43uaQ_IIDCfXl8dmJnfXYvzpA$
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