STAR Correlations and Fluctuations PWG

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

Dear Eugenia,

Thanks for the update.

Concerning your fits, using a Gaussian source here leads to discrepancies as you see between your data and fits. 

I agree that one should use the same parametrization for all kT intervals but your results clearly show that for higher kT fit does not work well.

You mentioned non-femtoscopic correlations, resonances, and this is true, but one needs some model calculation to indicate their impact on your measured correlation function.

For future, (if you have not done it yet) I would also suggest to see how simple Gaussian looks (without Coulomb correction) like to study the lambda parameter's behavior.

It looks for higher kT interval to get with such parametrization a better agreement between data and fit.

This should be included in your systematic uncertainty estimation.

As I wrote, it requires more investigation. Meantime please remove from your presentation all plots that did not get preliminary labels and discuss your results during the upcoming PWG CF meeting.

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 Eugenia Khyzhniak <eugenia.sh.el AT gmail.com> w dniu 02.10.2020, o godz. 21:35:

Dear Hanna,

Thank you for the comments!

Slide 4: I’ve changed the schematic picture.
Slide 5: Done!
Slide 6: I think that it is technical information and if someone will be interested in this information I would show slide from the back-up.
Slide 7: chi2/NDF depends on the multiplicity and kt bins.  
For example,
p+Au@200GeV (0-10 mult, 0.15-0.25 kt) : chi2/NDF = 11.85
p+Au@200GeV (0-10 mult, 0.45-0.55 kt) : chi2/NDF = 5.04
p+Au@200GeV (31-40 mult, 0.15-0.25 kt) : chi2/NDF = 1.11
p+Au@200GeV (31-40 mult, 0.45-0.55 kt) : chi2/NDF = 1.53
(here I show the first and last bins that I have).
>it looks like Coulomb correction here is applied incorrectly.
Coulomb correction here is applied correctly. Fitting quality varies because of the non-femtoscopic effects. At the different multiplicity and kt bin it would be different due to the resonances, jets, mini-jets etc. influence. Form of the emission source for small multiplicity is non-gaussian. It leads to a bad description of the correlation function amplitude and therefore has an influence on lambda.
>Can you remind me when did you present these plots?
In the previous presentation I show only one picture for both systems and Roy told me that it would be great if I could show pictures for different multiplicity and kt bins. So I inserted them in  this presentation. If you approve these plots I would update my preliminary request and upload it to the system.
Slide 8: I've updated my slide (kt definition on the 7 slide).
No, track’s resolution is not included yet.
Slide 9: I've updated my slide.

Thank you!
Best regards,
Eugenia

пт, 2 окт. 2020 г. в 17:58, Hanna Paulina Zbroszczyk via Star-cf-l <star-cf-l AT lists.bnl.gov>:

Dear Eugenia,

Please find my comments about your nice slides:

Slide 4: you present here a scheme of source emitting particles. According to the publication you cite below with a two-particle correlation, we do measure the correlation area, not a whole source. This is what we call homogeneity range. We do not measure the whole source itself, just a region of final state interaction and quantum statistical effects. I propose to slightly change the plot where just part of the source is studied. My other question also is about so many arrows at the plot. We measure momentum differences and having these all arrows, and it is hard to understand what exactly we measure and study. 

Slide 5:

- add Qinv definition

- you say that numerator of the correlation function includes Bose-Einstein statistics; however, when I take a look at the illustration of the correlation function, I see you have included Coulomb interaction as well. Please make them consistent: plot and description. 

- concerning your formula 2: define all quantities you mention there

Slide 6: 

I would suggest adding here pieces of information from slide 14 (from your backup).

Slide 7: 

What is the quality of the fitting for higher kT intervals (0.45 < kT< 0.55 for p+Au and d+Au data)? 

I see your fits don’t follow data; it looks like Coulomb correction here is applied incorrectly. 

There is a problem with the lambda parameter. Could you please remind me when did you get preliminary labels for them?

Can you remind me when did you present these plots? I went through your last few presentations, and I can’t find them. 

Am I missing something?

You didn’t show these kT bins during the last Collaboration Meeting.

Slide 8: 

Add kT definition.

Specify what do you mean by selection criteria for events, tracks, pairs.

Is track’s resolution included?

Slide 9: 

You mention that you see an interesting behavior for the lambda parameter. 

I see it might fit you apply as for these higher kT intervals; your fits do not follow data. I think it requires more investigation. 

With my best regards,

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 webmaster--- via Star-cf-l <star-cf-l AT lists.bnl.gov> w dniu 30.09.2020, o godz. 18:34:

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

Yevheniia Khyzhniak (eugenia.sh.el AT gmail.com) has submitted a material for a  
review, please have a look:
https://drupal.star.bnl.gov/STAR/node/52221

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