STAR Correlations and Fluctuations PWG

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

Dear Ke,

Many thanks for your responses.

About systematic uncertainties taking into account different ranges of fit.

Other studies show that what is extracted from fit parameters depends on the range you apply your fitting procedure. For K0S-K0S, it became one of the most significant sources of systematic uncertainties. It is worth checking it also here. 

Two cases are important to check:

1. How do the fitted parameters change if you include/exclude the first bin of your correlation function (as it has the largest statistical uncertainties).

2. How do the fitted parameters change when you apply your fitting to the correlation region only (lower k*) and if you include some points of the correlation function from the normalized region. 

Differences in fitted parameters between the default case and modified should be accounted for as one of the contributors to the systematic uncertainty.

Many 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 K.Mi <mike1996 AT mails.ccnu.edu.cn> w dniu 20.04.2023, o godz. 13:00:

Dear Hanna,

Thank you so much for the careful reading and comments. I add several slides for the details. 

The update slide can be found in this link:

star.bnl.gov

Please see my reply in line. 

Slide 3: Not sure if you need this to have put the slide, but can you explain how one can distinguish between coalescence and thermal scenarios with femtoscopy method?

We would like to keep this slide, this is a brief introduction about the big picture, mainly discuss the motivation about why we would like to start this analysis.

Some theory papers, like Phys.Rev.C 104, 024909(2021) and Acta Physics Polonica B 51, 1739 (2020), proposed that the emission source of coalescence deuteron and thermal deuteron may not same. Femtoscopy is sensitive to FSI, but also sensitive to the emission source size.  By comparing the CF with different approach, one may see some difference. 

Slide 4: Can you explain the parameters stored in the table? I understand separate columns but you did not explain separate rows. Do they refer to papers mentioned below? Can you indicate which one describes which parametrisation

Modified

Slide 6: As you know, in case of identical particle combinations, one deals with the QS effect as well. Can you add this to the slide?

Added in page15

Slide 7: what is the reference of shown figures? Can you add more details here? A description's of axes is missing. A question may appear here: how with negative f_0 would you recognize between 2nd and 3rd case? How to distinguish between attractive (& bound) and repulsive cases? 

Reference and x-title added. 

From the scattering theory, there’s no quantitative definition between repulsive and bound state, but usually a negative scattering length and small effective range is compatible with bound state. More details are added as a backup. 

 Slide 9: As you may know, recently, it was discussed (last CM and before) that nSigma for protons (and other particle species should be investigated as well) is not centered at 0 (for all FXT datasets, including 3 GeV). We need to know how did you deal with this shift in your analysis?

The nSigma_proton and Z_d shift are considered when calculating the particle purity, please see page28. 

Can you comment on such a high particle purity (above p>3-4 GeV/c in case of protons and deuterons) in case of such limited statistics shown at (pT, Y) plots?

The phase space in Slide7 is pT-y plot, the lower purity plot is purity as a function of momentum(p). The particle with pT ~ 3 GeV, the momentum p is > 4 GeV (roughly). At this region we still have statistics. 

 

Slide 10: What is the systematic effect of nSigma selection? Moreover, how do you shift non-zero nSigma?

The nSigma selection is not considered as a systematic source at the moment. For the PID part, only dca is considered. The shift of non-zero nSigma is considered when calculate the particle purity. 

What is the systematic contribution to different range fitting? Can you show also those effects?

Not clear about this question. Do you mean the systematics on R_G, f_0 and d_0? For this, page19, 20 are added. 

How about a resolution? Can you show these studies?

Added in page12

Can you list the effects you considered, also pointing out that you check not to contribute?

It would be good to have information on how they contribute (in %).

Added in page14

Slide 13: Figure 2: SMASH + Coalesce is shown only for the p-d case. Any reason why coalescence is not shown in the d-d case? I don't see any orange line for 20-40% or 40-60%.

It’s shown for both p-d and d-d. In d-d, the orange bands are overlapping with data. 

Slide 14: Figure 3: what is your interpretation that all of d-d case are below any model prediction? Moreover, according to the d-d case, they are all closer to the direct production.

"The upper limits of these bands, long dashed lines, stand for the calculations of SMASH plus deuterons from the coalescence after burner while the lower limits, short dashed lines, are for deuterons produced directly from SMASH”. All d-d points are even below all bands for all centrality classes. In the case of p-p, the first two centrality bins are closer to the thermal scenario, and two others to the coalescence case. Is this the main figure leading to the main paper's conclusion that deuterons are produced in the coalescence scenario? Please comment on this.

Please note the shadowed bands are divided by 2 for better presentation,  as the Legend wrote. So the shadowed bands are originally higher than data.  

The main propose of putting these two bands is we want to emphasise the time evolution of source.  From the data, one can not extract the time dependent source but only the Gaussian static source size. 

The solid bands represent the L-L fit results of SMASH+Coal (Static Gaussian source). This is same fitting as the data. And one can see the solid band and points are consistent.  From the Correlation Function plot, the coalescence one is more consistency with data shape, and from the source size plot, the R_G from L-L fit is consistent within data and coalescence model. 

To avoid the confusion, we remove the RMS bands, only show the L-L fit results for SMASH+Coal. 

 

Slide 15. Figure 4: I would like more details about extracting SI parameters here. You had to fix the source size to get these parameters. How do you know you assumed them correctly? I miss the discussion about the extraction of all these parameters. f0^-1 is around -0.2 fm^-1 and -0.4 fm ^-1. How did they lay on the conclusion about bound states? Both are negative. Refer to the comment from slide 7. 

The source size is not fixed. In the fitting, six parameters are free (f_0, d_0, source size * 4). The results in Figure 4 were coming from the multi-parameters fitting. 

For the conclusion, the repulsive and bound state will both lead to a negative f_0. According to our known knowledge and literature, in p-d case, the doublet spin contributes to He3 bound state, and the quartet spin state is a pure repulsive state. From data, it’s hard to separate these two spin states, so we can only extract the ‘spin-averaged’ f_0 and d_0.  And the f_0 is negative value, which is consistent with the He3 bound state in doublet and repulsive interaction in quartet. Due to the spin weight, the measured f_0 and d_0 is dominated by repulsive spin state. Similar to d-d case. 

Backup slides: Please consider discussing them during the presentation.

Added to the main presentation.

1. Can you explain in more detail how you extracted all: R, f0, and d0?

In L-L fitting, we generate a set of theory lines with small R, f_0 and d_0 steps. Each theory lines are compared with data, and a chi^2 value is calculated (shown in Slide17 and 18).  There’s a minimal chi^2 area in the map. For the fitting, we used TMinute package, and scan the parameters. 

The color-full maps seem to be inconsistent with extracted parameters shown with the correlation functions. f_0 in most backup slides is positive. 

Sorry, it’s a drawing issues, I draw the absolute value. All f_0 in this analysis is negative. Fixed already. 

2. Can you explain more details about Sim. Fit?

We assume the interaction parameter (f0, d0) is same in all centrality bins, and only source size changes. In the fitting procedure, 4 centrality data are considered at the same time. 

Thank you.

Best regards,

Ke

On 17. Apr 2023, at 16:41, Hanna Paulina Zbroszczyk <hanna.zbroszczyk AT pw.edu.pl> wrote:

Dear Ke,

Thank you for posting your presentation and the website of the paper proposal.

I think your analysis is mature and should move forward, here I need to clarify few things.

In general I think more details should be added for discussion.

My comments are related to your PWGC Preview Draft:

https://drupal.star.bnl.gov/STAR/system/files/202304_PWGC_preview_draft.pdf

I have the following comments:

Slide 3: Not sure if you need this to have put the slide, but can you explain how one can distinguish between coalescence and thermal scenarios with femtoscopy method?

Slide 4: Can you explain the parameters stored in the table? I understand separate columns but you did not explain separate rows. Do they refer to papers mentioned below? Can you indicate which one describes which parametrization?

Slide 6: As you know, in case of identical particle combinations, one deals with the QS effect as well. Can you add this to the slide?

Slide 7: what is the reference of shown figures? Can you add more details here? A description's of axes is missing. A question may appear here: how with negative f_0 would you recognize between 2nd and 3rd case? How to distinguish between attractive (& bound) and repulsive cases? 

 

 Slide 9: As you may know, recently, it was discussed (last CM and before) that nSigma for protons (and other particle species should be investigated as well) is not centered at 0 (for all FXT datasets, including 3 GeV). We need to know how did you deal with this shift in your analysis?

Can you comment on such a high particle purity (above p>3-4 GeV/c in case of protons and deuterons) in case of such limited statistics shown at (pT, Y) plots?

Slide 10: What is the systematic effect of nSigma selection? Moreover, how do you shift non-zero nSigma?

What is the systematic contribution to different range fitting? Can you show also those effects?

How about a resolution? Can you show these studies?

Can you list the effects you considered, also pointing out that you check not to contribute?

It would be good to have information on how they contribute (in %).

Slide 13: Figure 2: SMASH + Coalesce is shown only for the p-d case. Any reason why coalescence is not shown in the d-d case? I don't see any orange line for 20-40% or 40-60%.

Slide 14: Figure 3: what is your interpretation that all of d-d case are below any model prediction? Moreover, according to the d-d case, they are all closer to the direct production.

"The upper limits of these bands, long dashed lines, stand for the calculations of SMASH plus deuterons from the coalescence after burner while the lower limits, short dashed lines, are for deuterons produced directly from SMASH" .

All d-d points are even below all bands for all centrality classes. In the case of p-p, the first two centrality bins are closer to the thermal scenario, and two others to the coalescence case. Is this the main figure leading to the main paper's conclusion that deuterons are produced in the coalescence scenario? Please comment on this.

Slide 15. Figure 4: I would like more details about extracting SI parameters here. You had to fix the source size to get these parameters. How do you know you assumed them correctly? I miss the discussion about the extraction of all these parameters. f0^-1 is around -0.2 fm^-1 and -0.4 fm ^-1. How did they lay o the conclusion about bound states? Both are negative. Refer to the comment from slide 7. 

Backup slides: Please consider discussing them during the presentation.

1. Can you explain in more detail how you extracted all: R, f0, and d0?

The color-full maps seem to be inconsistent with extracted parameters shown with the correlation functions. f_0 in most backup slides is positive. 

2. Can you explain more details about Sim. Fit?

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 K.Mi <mike1996 AT mails.ccnu.edu.cn> w dniu 14.04.2023, o godz. 09:46:

Dear Hanna,

Please find the request material through the under links

•  Paper proposal in PWG(including comments reply):

star.bnl.gov

<eeBfPdm2eoBKnHEAAAAASUVORK5CYII=.png>

•  Preview draft:

star.bnl.gov

<eeBfPdm2eoBKnHEAAAAASUVORK5CYII=.png>

•  Webpage:

star.bnl.gov

<eeBfPdm2eoBKnHEAAAAASUVORK5CYII=.png>

Thank you.

Best regards,

Ke

On 11. Apr 2023, at 20:52, Hanna Paulina Zbroszczyk <hanna.zbroszczyk AT pw.edu.pl> wrote:

Hi Ke,

Can you prepare one file including your initial presentation: 

star.bnl.gov

And your responses as well?

star.bnl.gov

I will have some comments, but before I respond I need to see the current draft of the presentation you intend to show during preview.

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 K.Mi <mike1996 AT mails.ccnu.edu.cn> w dniu 10.04.2023, o godz. 17:28:

Dear Convenors,

This is a gentle reminder that we would like to request the PWGC preview for the ‘Light Nuclei Femtoscopy at 3 GeV’ paper.

Here’s the related links: 

-> Paper proposal in PWG: https://drupal.star.bnl.gov/STAR/blog/kmi/20221222PaperProposalLightNucleiCF3GeV

-> Webpage: https://www.star.bnl.gov/protected/bulkcorr/kmi/paper/LightNuclei/LightNuclei_CF.html

Could you help to arrange that? And kindly let us know if Please more information is needed. 

Thank you.

Best regards, 

Ke for the PAs

On 3. Apr 2023, at 12:04, K.Mi <mike1996 AT mails.ccnu.edu.cn> wrote:

Dear Convenors,

We would like to request PWGC preview for the ‘Light Nuclei Femtoscopy at 3 GeV’ paper.

The detailed information can be found from the following links:

-> Paper proposal in PWG: https://drupal.star.bnl.gov/STAR/blog/kmi/20221222PaperProposalLightNucleiCF3GeV

-> Webpage: https://www.star.bnl.gov/protected/bulkcorr/kmi/paper/LightNuclei/LightNuclei_CF.html

Please kindly let us know if any other information is needed. Thank you.

Best regards,

Ke