STAR Correlations and Fluctuations PWG

[ShinIchi Esumi <esumi.shinichi.gn AT u.tsukuba.ac.jp>]

Dear Pawel

I’ve been assigned to review your QM poster by Rongrong. You have prepared your slide format with 5 pages, so that you can explain in a few minutes (within an assigned time slot?), which is very good. 

One comments on your PID plots on page 2, it seems that you change detector combinations depending on the momentum of the particles, which would be OK as you exactly do in your analysis, but if you apply the exact same condition for such a PID plot, it makes odd effects on the PID plots, where we see a sudden jump in the 2D distribution, for example, at ~0.8GeV/c for proton, ~0.4GeV/c for kaon, and ~0.2GeV/c for pion, they are coming from the change of detector acceptance/efficiency including possible contamination from other particles. So I would suggest to make such plots in cleaner way, just always requiring both TOF mass square and TPC dE/dx cut simultaneously to make such 3 plots, or just show "mass^2 (or beta) vs p” and “dE/dx vs p” without PID cut and indicate pi, K and p… However your plots in the page 2 would give us some confidence/confirmation of your PID cuts, so please judge the jump yourself, that is reasonable or not, whether they are expected from different detector acceptance/efficiency including possible contamination. 

One question on page 3 is that this asymmetry parameter mu is applied only in Rout direction, why? There could be also similar shift in all 3 directions, or? Maybe you do assume the asymmetry only in duration time wise? Or maybe this is a rest flame of the pair with an assumption of the same geometry in all 3 directions? Since you do the analysis shown in the page 4 only in k*_out direction, so it might not matter much? Is this correlation function a projection in 1D from the full 3D function? Have you try to separate Coulomb and other effects by making double ratio of unlike-sign over like-sign ratio? For example, by making the ratio of C2(U.S.) / C2_rev(L.S.), where the revised C2 could be taken as C2_rev = 1+(1-C2)? All of these comments in this 2nd paragraph might be for your future studies. 

The last comment on your final plots on page 5, please plot the 4 different color points slightly apart from each other in horizontally, so that we can see the points more clearly including statistical and systematic errors. I would also suggest a similar color (or symbol) for like-sign pair results, that can be made somewhat more clearly different appearance from the unlike-sign pair results. For example, with open and filled symbol for unlike- and like-sign pairs etc. And all 4 points to be separated horizontally at least more than about 2 times the symbol size. I would also have vertical range R = [0, 20] fm and mu = [-10,10] fm and have dashed line at mu=0.

Best regards, ShinIchi

On Mar 25, 2022, at 19:52, Paweł Szymański via Star-cf-l <star-cf-l AT lists.bnl.gov> wrote:

Dear All,

I checked whether resonance decays were considered in the paper about pion femtoscopy (Beam energy dependent two-pion interferometry and the freeze-out eccentricity of pions in heavy ion collisions at STAR), and they were not included in this analysis.
The influence of resonance decays (or more precisely, the difference between all and primary particles correlation function) is rather model-dependent. So it will be better to describe it as the model predictions.

I would like to put a statement on the poster: "Influence of particles from resonance decays are not considered." 

My poster is updated (https://drupal.star.bnl.gov/STAR/system/files/QM2022_poster_PSzymanski_0.pdf), and I ask for the STAR Preliminary labels for size and asymmetry system dependence.

Best regards,

Pawel

 

pon., 14 mar 2022 o 19:18 webmaster--- via Star-cf-l <star-cf-l AT lists.bnl.gov> napisał(a):

Dear star-cf-l AT lists.bnl.gov members,

Pawel Szymanski (pawszy91 AT gmail.com) has submitted a material for a review, 
please have a look:
https://drupal.star.bnl.gov/STAR/node/58863

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