STAR Correlations and Fluctuations PWG

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

Dear Chuan and other PAs,

As already mentioned, I am glad this analysis is moving forward.

Following our yesterday's discussion, I have the following comments and requests regarding your paper proposal (some of them may overlap with Grigory's ones):

General comments: I encourage you to make stronger physics motivation. I understand that it relates to studies of strong interaction, so I suggest building your story this way.

Another essential aspect is that before we move forward, we need to know every detail of your analysis. Please include all analysis details, ensuring you discuss (even as a backup if you don't want to significantly extend your presentation's main part).

- make sure you list all your cuts applied at the event, track, and pair selection level.

Mention all their default values (and later, how you change them to determine systematic uncertainties).

It is essential for all systems you discuss: p-p, p-\Lambda, p-\Xi.

- discuss two-track effects in detail: splitting, merging (all systems you discuss: p-p, p-\Lambda, p-\Xi)

- mention and discuss all corrections: purity, resolution, feed-down contribution, side-band, and all you included in your studies (all systems you discuss: p-p, p-\Lambda, p-\Xi).

-Figure 3: consider how to report your results as dashed lines suggest they are fitting curves which is not the case.

I suggest extracting the source size (together with parameters of interactions) from fitting and, as a separate figure to show model prediction.

- You use LL mode to extract source sizes and interaction parameters, but for the UrQMD model, you calculate correlation functions using the CRAB approach.

CRAB already has included some assumptions about interactions. Make sure you use the same approach (the same parametrization) in the case of experimental data and model.

- Figure 4 shows very modest uncertainties of source sizes. Can you explain how you calculate uncertainties in the case of radii and parameters of the strong interaction?

- You extracted only one set of parameters (f0, d0) for each system. What about singlet and triplet? What are the fitting results in the case of singlet and triplet states considered separately?

- discuss more details about extraction of the parameters: source sizes, f0, d0, discuss shapes of the countours.

- Slide 18 confuses me. I understand you used CRAB to calculate correlations for UrQMD data. What did you do next? Did you extract interaction parameters (and source size) with the LL model? We need to understand what parametrization is included in CRAB you used.

- Discuss your systematics in detail.

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 Grigory Nigmatkulov via Star-cf-l <star-cf-l AT lists.bnl.gov> w dniu 02.06.2023, o godz. 12:29:

Hi Chuan and PAs,

First, I would like to congratulate you with these brilliant and important results!

Please find some questions for your nice study.

General questions:

- Did you take the influence of the momentum resolution of Lambda and Xi, not only p?

- Did you check that protons are not daughter tracks of Lambdas from decays of Lambda->p and Xi->Lambda->p?

- Did you check the two-track effects (merging and splitting) affects daughter protons? How did you do that?

nHits variation and delta-eta vs. delta-phi (not phi*) cuts are quite insensitive to track-merging and track-splitting effects.

- Could you demonstrate the effects of the track-merging and splitting removal procedure?

- When studied pLambda and pXi interactions have you looked at the CFs when hyperons

are selected outside of the signal peak (sidebands)? Could you demonstrate it?

- For final state interaction parameters:

  -- For p-p: I suggest you do add a plot with the world systematics (STAR at 200 GeV, ALICE, others)

  -- For p-Lambda: Please add world systematics (STAR and results from CEBAF)

Abstract:

Please proofread the text. For example:

parametrs -> parameters

remove comma at the of the first line,

etc.

Please make clear what you do with the UrQMD + CRAB and LL model.

slide 3:

Track selection says that transverse momentum criteria is [0.15, 10] GeV/c. Is that for all particles?

Is it true for protons?

slide 5:

Why do you think that the listed values are the sources of systematic uncertainty (especially nsigma values)?

Do you apply purity correction to the correlation functions?

slide 9:

As we discussed yesterday, please update the figure. For example, one could change MC curves with

the markers. Usually curves represent the fit of the function to the data.

Could you show the fits to the data?

pXi should be redrawn because it is completely misleading. Curve does not represent the fit.

slide 10:

Right figure:

- Please explain what pLambda(t) and pLambda(s) are.

- The label says Model. Do you mean UrQMD? If yes, please replace Model with UrQMD

- Why no uncertainties on d0 and f0 are shown for pp pairs?

slide 11:

Please check the uncertainties carefully and write those according to the rounding rules.

Are those uncertainties statistical only? What are the systematic uncertainties on the values?

slide 17:

It would be good to add it to the main figures.

Can you explain why some of the contours  have a "funny" shape? For example, black contour on the right figure?

Cheers,

Grigory

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