Spectra and ratios of identified particles in Au+Au and d+Au collisions at sqrt(s_NN)=200 GeV

TL;DR

This paper reports on the transverse momentum spectra and particle ratios in Au+Au and d+Au collisions at 200 GeV, revealing baryon-to-meson ratio enhancements at intermediate p_T and similarities between certain collision classes.

Contribution

It provides detailed measurements of identified particle spectra and ratios across different collision centralities, highlighting the baryon enhancement phenomenon and its comparison between Au+Au and d+Au collisions.

Findings

Baryon-to-meson ratios are significantly enhanced at intermediate p_T in both collision types.

The enhancement increases with collision centrality.

Similar particle ratio patterns are observed in peripheral Au+Au and central d+Au collisions with comparable participant nucleons.

Abstract

The transverse momentum (p_T) spectra and ratios of identified charged hadrons (\pi^+/-, K^+/-, p, p^bar) produced in sqrt(s_NN)=200 GeV Au+Au and d+Au collisions are reported in five different centrality classes for each collision species. The measurements of pions and protons are reported up to p_T=6 GeV/c (5 GeV/c), and the measurements of kaons are reported up to p_T=4 GeV/c (3.5 GeV/c) in Au+Au (d+Au) collisions. In the intermediate p_T region, between 2--5 GeV/c, a significant enhancement of baryon to meson ratios compared to those measured in p+p collisions is observed. This enhancement is present in both Au+Au and d+Au collisions, and increases as the collisions become more central. We compare a class of peripheral Au+Au collisions with a class of central d+Au collisions which have a comparable number of participating nucleons and binary nucleon-nucleon collisions. The p_T dependent particle ratios for these classes display a remarkable similarity, which is then discussed.