STAR Correlations and Fluctuations PWG

[Nu Xu <nxu AT lbl.gov>]

Dear Dear  Sneha,

Let me make the last comment on this issue:
For p-value, when it is less than 0.05, the fit result is considered to be 
ok. The lower plot on slide 14 shows, however, p-values are larger than 0.05 
for mT>=0.5 GeV from both alpha =2 and Levy fits. To me it is difficult to 
see the difference, especially if one makes a plot with Chi^2/def.

I sign off the talk for now. But one should really think how to make the 
discussion regarding the goodness of the fit. I am sure that we will again 
discuss about this when we write the paper.

Best regards,
Nu
 
> On Nov 2, 2024, at 9:52 AM, Bhosale Sneha <bhosales AT staff.elte.hu> wrote:
> 
> Dear Nu,
> Thank you for the email. I now made clear that this is in fact indeed on 
> the slide and put titles with large font to the chi^2 difference and 
> p-value plots, on slide 14. 
> 
> The updated version is now available here for your review: (version 4)     
> https://drupal.star.bnl.gov/STAR/node/69661
> 
> Thank you.
> Best regards,
> SnehaFrom: Nu Xu <nxu AT lbl.gov>
> Sent: Saturday, November 2, 2024 5:35 PM
> 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,
> Is it possible to make it clear that Slide 14 is, infact, a displace of 
> p-vale?
> At the moment, as far as I can see, it is either (chia^2_apha =2 - chir^2) 
> vs. mt or Count. Lev. vs.mt.?????!!!
> 
> Regards,
> Nu
> 
> 
> 
> > On Nov 2, 2024, at 7:06 AM, Bhosale Sneha <bhosales AT staff.elte.hu> wrote:
> > 
> > Dear Nu,
> > Thank you so much for the email. Here are my responses/explanation for 
> > you comments;
> >  1) Plot The bottom right plot in slide 14 already shows the confidence 
> > levels (p-values) that you requested. This plot compares two cases:
> > Red triangles: fits with free α
> > Black triangles: fits with fixed α = 2.0 (Gaussian case)
> > 2) The y-axis shows the confidence levels on a logarithmic scale from 
> > 10^-7 to 1, clearly demonstrating the several orders of magnitude 
> > improvement mentioned in the bullet points when comparing free α fits to 
> > Gaussian fits. This plot directly addresses the need for experimental 
> > evidence of the improved confidence levels rather than just stating the 
> > claim. Also, chi2/NDF difference plot is on top of the confidence level 
> > plot.
> >  3)Slide 11: Yes, all the parameters are there in traditional gaussian 
> > fits
> > Thank you.
> > Best regards,
> > Sneha
> > 
> > From: Nu Xu <nxu AT lbl.gov>
> > Sent: Saturday, November 2, 2024 2:27 PM
> > 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,
> > 
> > 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