STAR Correlations and Fluctuations PWG

[Hanna Paulina Zbroszczyk <hanna.zbroszczyk AT pw.edu.pl>]

Dear Ke Mi,

Please find below comments to your nice presentation:

General comment: as you want to show preliminary results, you should prepare a page with preliminary plots. When ready, I will create a link accessed from this page:

https://drupal.star.bnl.gov/STAR/blog/gos/correlations-and-fluctuations-preliminary-plots

Slide 7: what is the reason to place here so many details about particle reconstruction?

Are you going to discuss details about these differences?

If not, I recommend providing general info about particle reconstruction; for many cases, the selection criteria are the same (e.g., nSigma, rapidity, etc..). This table can be moved to backup, you can provide just general information. 

Slide 9: Your definition of k* is incorrect. k* calculated in PRF reference means momentum of the first particle of the pair.

Do you consider PRF reference? Do you use k* variable? Using PRF is correct for nonidentical particles combinations. You can add a simple plot illustrating what k* considered in PRF reference is. 

Having here cascade purity, it would be nice to have proton’s purity too. 

I also don’t understand why you define proton’s purity as P(proton) = S/(S+B) * Fr(proton).

You should consider PID probability instead of S/(S+B) in the case of protons.

Slide 10: You state here ~3.9\sigma (central) and ~4\sigma (peripheral), but it is valid only if you assume Coulomb interaction in case of source with radius = 3 fm (central) and radius = 2 fm (peripheral). These numbers would change if you consider different source sizes. From these plots, I don’t understand why you choose these source sizes for your correlation functions. Add explanation here. 

From other baryon studies, we know that source sizes should be larger, for example, for the proton-proton case, in the case of central collisions, source size can be around 4 fm and bigger. Take a look here (for sqrt(sNN) = 200 GeV source sizes are even larger):

https://doi.org/10.1016/j.nuclphysa.2018.10.072

Also, you should mention that feed-down correction taking into account residual correlations is not implemented here.

Slide 11: I would be very careful showing this result. You show a ratio of two correlation functions taking into account sources of sizes of 2 and 3 fm, but you don’t prove they are the best fits. You never show the fit taking into account full FSI for a single correlation function. You also show the ratio of functions assuming just Coulomb interaction, indicating it is more or less close to the unity. However, it can be just an example of such source sizes.

Your statement that a ratio of correlation functions for small and large systems provides direct access to the strong interaction needs more investigation. Instead, I would mention that it can provide direct access, but more study is necessary. 

Thanks,

Hanna

Hanna Paulina Zbroszczyk

PhD DSc Eng, Professor WUT

E-mail: hanna.zbroszczyk AT pw.edu.pl

Tel: +48 22 234 5851 (office)

Address:

Warsaw University of Technology

Faculty of Physics

Nuclear Physics Division

Koszykowa 75

Office: 117b (via 115)

00-662 Warsaw, Poland

Wiadomość napisana przez Xiaofeng Luo via Star-cf-l <star-cf-l AT lists.bnl.gov> w dniu 08.04.2021, o godz. 17:44:

Hi Ke Mi,

    Nice presentation.
    Please find my comments and suggestions below :

    1. Slide 6,  GeV/C  -> GeV/c,  protonDCA -> DCA of proton < 0.5 cm , nsigma -> {N_{\sigma},p|<2
                       mass^2proton -> M^2

    2. In some legend, the symbol of Xi should be consistent.

    With those implemented, I sign off.

Thank you,
Best Regards,
Xiaofeng

On 2021/4/8 19:56, webmaster--- via Star-cf-l wrote:

Dear star-cf-l AT lists.bnl.gov members,

Ke Mi (mike1996 AT mails.ccnu.edu.cn) has submitted a material for a review,
please have a look:
https://drupal.star.bnl.gov/STAR/node/54563

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