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[[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
- From: Sooraj Radhakrishnan <skradhakrishnan AT lbl.gov>
- To: STAR Papers Discussion List <starpapers-l AT lists.bnl.gov>, STAR Correlations and Fluctuations PWG <star-cf-l AT lists.bnl.gov>
- Subject: [[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: Mon, 22 Jul 2024 11:40:31 -0700
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 CF PWG. 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
Physicist Postdoctoral Affiliate
Lawrence Berkeley National Lab
MS70R0319, One Cyclotron Road
- [[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, Sooraj Radhakrishnan, 07/22/2024
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