STAR Correlations and Fluctuations PWG

[Nu Xu <nxu AT lbl.gov>]

Dear Sneha,

Thank you for the updated version.
Here are my comment/suggestions on the v3:
(1) slide 14 - "Confidence levels (p-values) improve by 1-3 orders of 
magnitude with free 𝜶”: show a plot or remove the claim;
(2) "(ii): for all these fits, chi^2/NDF is approximately the same, around 1. 
It is however not a good number to estimate goodness-of-fit, as for large NDF 
(number of degrees of freedom) values very small changes in chi^2 can lead to 
large changes in probability. Thus, it is more important to show chi^2, but 
even more importantly, the probability (p-value or confidence level). “  So 
show a figure with p-values. Do NOT just claim, show the experimental 
figures!!!
(3) slide 11: are parameters already in the ’transitional fits with 
alpha=2”???

Regards,
Nu

> On Nov 2, 2024, at 2:49 AM, Bhosale Sneha <bhosales AT staff.elte.hu> wrote:
> 
> Dear Nu,
> Thank you so much for the email. Since my talk is on 5th of November 
> 2024(Tuesday) I mostly removed the things you asked for and here are my 
> responses/explanation for you comments;
>  1) A slide could be added to explain the physics meaning but given that 
> now the talk is very close (Tuesday), I cannot do anything else but just 
> remove these mentions. I do think the concept is important but it would 
> probably need discussions within the PWG how the explanatory slides should 
> look like, so for the sake of time, I removed these statements.
>  2) For the first point (i), "Lévy-scale R" is the size parameter of the 
> Lévy distribution, meaning the size of the source. For the second point 
> (ii): for all these fits, chi^2/NDF is approximately the same, around 1. It 
> is however not a good number to estimate goodness-of-fit, as for large NDF 
> (number of degrees of freedom) values very small changes in chi^2 can lead 
> to large changes in probability. Thus, it is more important to show chi^2, 
> but even more importantly, the probability (p-value or confidence level). 
> Nevertheless, I now wrote on the slide that chi^2/NDF is approximately 1 
> for all fits.
>  Actually, the number of parameters differs just by one, alpha is the only 
> additional parameters. More accurate description can be claimed because of 
> the difference in the goodness-of-fit. But for the sake of reaching a good 
> consensus, I removed this wording.
>  The updated version is now available here for your: (version 3)    
> https://drupal.star.bnl.gov/STAR/node/69661
>  Thank you again. 
>  Best regards,
> Sneha
> 
> From: Nu Xu <nxu AT lbl.gov>
> Sent: Saturday, November 2, 2024 7:46 AM
> To: Bhosale Sneha <bhosales AT staff.elte.hu>
> Cc: Nu Xu <nxu AT lbl.gov>; STAR Correlations and Fluctuations PWG 
> <star-cf-l AT lists.bnl.gov>
> Subject: Re: [[Star-cf-l] ] WPCF 2024 talk
>  Dear Sneha,
> 
> Thanks for the updated presentation. I do have trouble with some claims 
> shown in the present slides:
> 
> 1) The term Levy Walk mentioned in slides 6, 13, 15, and 17.
> We throw the term to audiences without explanations, it is very confusion. 
> For this talk if the concept is needed, then provide the physics meaning. 
> It it is not needed for this talk, take them all out of the presentation.
> 
> 2) slide 14: (i) What does it mean by “Levy-scaled R”? (ii) right two 
> plots: are these the chi^2/per degree of freedom? If it is, please note 
> them so, for example, chi^2/pdf.
> If I understand, there are many more parameters in the so-called Levy-fit, 
> including epsilon_o, epsilon_s, epsilon_l?
> 
> A fit with many more parameters, in this case is the Levy-fit, can we 
> really claim “… more accurate shape and size” shown on slide 5?
> 
> Best regards,
> Nu 
> 
> > On Nov 1, 2024, at 3:24 AM, Bhosale Sneha <bhosales AT staff.elte.hu> wrote:
> > 
> > Dear Nu, 
> > 
> > I wanted to follow up on my response to your helpful feedback on my 
> > presentation. I have incorporated the suggested changes and provided 
> > explanations where needed, including adjustments on slides 10, 11, 14, 
> > and 15, along with the reference addition. My responses to your 
> > suggestions can be found in below email. 
> > 
> > The updated version is now available here for your review: 
> > https://drupal.star.bnl.gov/STAR/node/69661
> > 
> > Thank you once again for your valuable insights, and I look forward to 
> > any further suggestions you may have.
> > 
> > Best regards,
> > Sneha
> > 
> > 
> > 
> > Get Outlook for AndroidFrom: star-cf-l-request AT lists.bnl.gov 
> > <star-cf-l-request AT lists.bnl.gov> on behalf of Bhosale Sneha 
> > <bhosales AT staff.elte.hu>
> > Sent: Wednesday, October 30, 2024 4:58:25 PM
> > To: STAR Correlations and Fluctuations PWG <star-cf-l AT lists.bnl.gov>
> > Cc: Nu Xu <nxu AT lbl.gov>
> > Subject: Re: [[Star-cf-l] ] WPCF 2024 talk
> >  Dear Nu,
> > Thank you so much for he feedback following is my response;
> >     • Slide 11:  I incorporated your suggestions, and have only one 
> > nozero digit in all of the uncertainties, and rounded the parameter 
> > values accordingly.
> >     • Slide 11: Thank you for pointing it out, it surely needs an 
> > explanation. I added the explanation of these parameters to slide 10 
> > where they are discussed in last bullet point; let me also mention here 
> > that this essentially handles all residual, non-femtoscopic background, 
> > coming from energy and momentum conservation, resonance decays, bulk flow 
> > phenomena, minijets.
> >     • Slide 14: I agree. I now include the chi^2 difference and the 
> > p-value (confidence level) for both fits. The reference has also been 
> > added for published data.
> >     • Slide 15: Agree, it does need a bit explanation. Now I added 3 
> > bullet points as an explanation.
> > I have incorporated your suggestion in version 2. Please have a look.
> > https://drupal.star.bnl.gov/STAR/node/69661
> > Thank you.
> > Best regards,
> > Sneha
> > 
> > From: star-cf-l-request AT lists.bnl.gov <star-cf-l-request AT lists.bnl.gov> 
> > on behalf of Nu Xu <nxu AT lbl.gov>
> > Sent: Wednesday, October 30, 2024 12:17 AM
> > To: STAR Correlations and Fluctuations PWG <star-cf-l AT lists.bnl.gov>
> > Cc: Nu Xu <nxu AT lbl.gov>
> > Subject: Re: [[Star-cf-l] ] WPCF 2024 talk
> >  Hi Sneha,
> > 
> > Thank you for the draft for WPCF2025. I have the following suggestions 
> > for your consideration:
> > 1) slide 11 - middle plot: those numbers listed there are too precise, 
> > perhaps meaningless. For example, lambda could be 0.99+-0.05, R_out could 
> > be 6.7+-0.2 fm and so on;
> > 2) slide 11: what are those epsilons? Why do we need them? Any physics 
> > meanings of these parameters?
> > 
> > 3)  slide 14 - last three bullets: instead of these claims, can we simply 
> > list the fitting results of chi^2/pdf from both alpha=2 and free alpha 
> > fits? For the alpha =2 data, a reference should be provided.
> > 
> > 4) slide 15: what is "Levy walk”? One should explain it in the talk, not 
> > just point to another talk in my view;
> > 
> > That is all for now. 
> > Best regards,
> > 
> > Nu
> > 
> > 
> > > On Oct 29, 2024, at 5:26 AM, Bhosale Sneha <bhosales AT staff.elte.hu> 
> > > wrote:
> > > 
> > > Dear All,
> > > I would like to let you know that the WPCF conference agenda has been 
> > > released, and my talk is scheduled for the 5th of November 2024, a week 
> > > from now. I would greatly appreciate if you could review my 
> > > contribution before the 4th of November. Your feedback and suggestions 
> > > would be invaluable in improving the presentation.
> > > 
> > > https://drupal.star.bnl.gov/STAR/node/69661
> > > 
> > > Thank you in advance for your time and support.
> > > 
> > > Best regards,
> > > SnehaFrom: star-cf-l-request AT lists.bnl.gov 
> > > <star-cf-l-request AT lists.bnl.gov> on behalf of Bhosale Sneha 
> > > <bhosales AT staff.elte.hu>
> > > Sent: Wednesday, October 23, 2024 4:51 PM
> > > To: STAR Correlations and Fluctuations PWG <star-cf-l AT lists.bnl.gov> 
> > > <star-cf-l AT lists.bnl.gov>
> > > Subject: [[Star-cf-l] ] WPCF 2024 talk
> > >  Dear All,
> > > Please have a look at my contribution for WPCF2024 talk and let me know 
> > > your views.
> > > 
> > > https://drupal.star.bnl.gov/STAR/node/69661
> > > 
> > > Thank you very much for considering my request.
> > > 
> > > Best regards,
> > > Sneha