STAR Correlations and Fluctuations PWG

[傅川 <fuchuan AT impcas.ac.cn>]

Dear Convenors and All,

           The following documents are ready for PWG review and please find 
them below:
Paper website:
https://drupal.star.bnl.gov/STAR/blog/fuchuan/Baryon-Baryon-CF-3GeV-0

1) Paper draft:
 
https://drupal.star.bnl.gov/STAR/system/files/3GeV_pp_pL_pXi_CF_PaperDraft_v1.pdf
2) Supplemental materials:
https://drupal.star.bnl.gov/STAR/system/files/Supplemental_materials_v1.pdf
3) Analysis note:
https://drupal.star.bnl.gov/STAR/system/files/Analysis_note_3GeV_pp_pL_pXi_CF_v1.pdf
4) Response to PWGC preview:
https://drupal.star.bnl.gov/STAR/system/files/PWGC-response_0.pdf

Your comments/suggestions are helpful for us and,
we would appreciate if you could take a look at those documents.

Thank you and best regards,
Chuan, Zhi and Yingjie for the PAs

-----原始邮件-----
发件人:"Sooraj Radhakrishnan" <skradhakrishnan AT lbl.gov>
发送时间:2024-07-23 02:40:31 (星期二)
收件人: "STAR Papers Discussion List" <starpapers-l AT lists.bnl.gov>, "STAR 
Correlations and Fluctuations PWG" <star-cf-l AT lists.bnl.gov>
抄送: 
主题: [[Star-cf-l] ] Notes for PWGC preview (07/19/2024): Measurements of 
Proton−Proton, Proton−Λ and Proton−Ξ- Correlation Functions in sqrt{sNN} = 3 
GeV Au+Au Collisions at RHIC

Date: 07/19/2024   

Participants: Chuan Fu, Ke Mi. Yingjie Zhou, Youquan Qi,Zhi, Qin, Jae Nam, 
Hanna Zbroszczyk,Prithwish Tribedy, Subhash Singha, Isaac Mooney, Nihar 
Sahoo,Yi Yang, Shuai Yang, Yue Hang Leung, ShinIchi Esumi, Sooraj 
Radhakrishnan    

Title: Measurements of Proton−Proton, Proton−Λ and Proton−Ξ- Correlation 
Functions in sqrt{sNN} = 3 GeV Au+Au Collisions at RHIC   
PAs: X. Dong, C. Fu, X.F. Luo, K. Mi, Z. Qin, Y.Q. Qi, S.S. Shi, Y.P. Wang, 
N. Xu, Z.G. Xiao, Y.J. Zhou   
Target journal: PRL   
Proposal page: 
https://drupal.star.bnl.gov/STAR/blog/fuchuan/Baryon-CF-paper-3-GeV   
Presentation: 
https://drupal.star.bnl.gov/STAR/system/files/Measurements_pp_pLam_pXi_CF_PWGC_2024_v1.pdf
   

The PWGC panel previewed a paper proposal from CFPWG. The panel found that 
the analysis is mature and results are important and interesting, and the 
paper should move forward. The journal choice was also found to be 
appropriate. The following points were discussed.   

Q: On S.8, what are the correlation functions used for the evaluation of feed 
down contributions?   
A: For p - Lambda correlations, these are using p - Sigma correlations from 
model calculations (S.26)   

Q: Is there a model uncertainty in evaluation of feed-down contribution? Do 
you use more than one model?   
A: For p+p, the contribution is very small. For p - Lambda we use different 
models. For the feed-down fractions we use values from thermal model and 
UrQMD   

Q: What are the feed-down fraction for protons and Lambda at 3 GeV?   
A: This is shown on S.26, for Lambda the feedodown fraction is 30%   

Q: For p - Lambda, the UrQMD has much different radius than in data. But in 
Fig.2, the correlation function from UrQMD is very close to that in data. Why 
is this so?    
A: There is difference between L-L fit and UrQMD in Fig.2. The data - UrQMD 
difference can also be seen on S.29   

Q: On S.8, what are a and b for the merged pair rejection?   
A: These are cuts in Delta phi and Delta ets. The values of a and b are 
different for different analyses. More details can be found in S.19. These 
are varied for systematic uncertainty evaluation   

Q: On S.12, do you have the chi2 for these fits?   
A: The chi2/ndf are shown on S.23. It is around 3.    
Q: Isn't this large?   
A: The contour of variation corresponds to the contour plots in Fig.3. The 
quoted fit parameters have the minimum chi2/ndf   

Q: On Fig.1, the acceptances are slightly different for p-p and p-Lambda, and 
also different for p-Cascade. Does this make an impact on extracted values?   
A: For p-p, we change the minimum pT cut from 0.4 GeV/c to 0.5 GeV/c. The 
difference in correlation functions are very small. For p-Cascade, we have to 
use the acceptance because of limited statistics    

Q: The momentum smearing correction is listed as largest contributor to 
systematic uncertainties. How is this evaluated?   
A: We smear the data with the momentum resolution from embedding and evaluate 
the impact. This is discussed on S.20   

Q: Are there any constraints on f0 or d0 when doing L-L fits?   
A: No, there are no constraints?   
Q: Are the extracted f0 and d0 for p-Lambda consistent with that shown in QM 
preliminary?   
A: Yes, the values and errors are consistent    

C: The extracted f0, d0 values, particularly for p-p are very precise. This 
can be highlighted in the abstract   
A: Yes, we will consider    

Q: We have measurements of other nucleon-nucleon and nucleon-hyperon 
correlations. Why are they not discussed in this paper?   
A: These measurements are not published and its not clear which analyses will 
be published first   

Q: In Fig.4, is the one labelled PRC from measurement?   
A: Yes, this is from low energy scattering measurement    
C: In that case, would be good to label clearly   
A: Yes, will change    

Q: Does ALICE have measurements of p-p, p-Lambda?   
A: No. These are the first measurements    

Q: In the abstract it is mentioned that the measurements can constrain the 
interactions in neutron stars, but the densities are very different. How do 
you address this? Should this be in the abstract?   
A: The measurements can still offer constraints to model calculations. We 
think it is good to have in the abstract   

Q: Can we compare to previous measurements of proton - Omega and Lambda - 
Lambda correlations in Figure 4?   
A: We want to focus on the high precision measurements from this analysis on 
Fig.4    

-- 
Sooraj Radhakrishnan
Research Scientist,         
Department of Physics
Kent State University         
Kent, OH 44242         

Physicist Postdoctoral Affiliate          
Nuclear Science Division
Lawrence Berkeley National Lab
MS70R0319, One Cyclotron Road
Berkeley, CA 94720
Ph: 510-495-2473
Email: skradhakrishnan AT lbl.gov


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