Centrality dependence of $p_{T}$ spectra for identified hadrons in Au+Au and Cu+Cu collisions at $\sqrt{s_{NN}}= 200$ GeV

TL;DR

This study uses a quark combination model to analyze how the transverse momentum spectra of identified hadrons depend on collision centrality in Au+Au and Cu+Cu collisions at 200 GeV, revealing that collective velocity depends only on participant number.

Contribution

It introduces a systematic analysis of centrality dependence of hadron spectra and collective flow using a quark combination model across different collision systems at 200 GeV.

Findings

The $p_T$ spectra and $R_{CP}$ are well described for both Au+Au and Cu+Cu collisions.

The average collective transverse velocity $<eta (r)>$ depends only on the number of participants.

The model's results are consistent across different collision systems, indicating a universal behavior.

Abstract

The centrality dependence of transverse momentum spectra for identified hadrons at midrapidity in Au+Au collisions at $\sqrt{s_{NN}}= 200$ GeV is systematically studied in a quark combination model. The $\mathrm{{p}_{T}}$ spectra of $\pi^{\pm}$, $K^{\pm}$, $p(\bar{p})$ and $\Lambda(\bar{\Lambda})$ in different centrality bins and the nuclear modification factors ($R_{CP}$) for these hadrons are calculated. The centrality dependence of the average collective transverse velocity $<\beta (r)>$ for the hot and dense quark matter is obtained in Au+Au collisions, and it is applied to a relative smaller Cu+Cu collision system. The centrality dependence of $\mathrm{{p}_{T}}$ spectra and the $R_{CP}$ for $\pi^{0}$, $K_{s}^{0}$ and $\Lambda$ in Cu+Cu collisions at $\sqrt{s_{NN}}= 200$ GeV are well described. The results show that $<\beta (r)>$ is only a function of the number of participants $N_{part}$ and it is independent of the collision system.