Identified Hadrons and Jet Chemistry for p+p and Au+Au Collisions at RHIC

TL;DR

This paper measures identified hadron spectra and nuclear modification factors in p+p and Au+Au collisions at RHIC, testing pQCD predictions and exploring jet quenching effects at high transverse momentum.

Contribution

It provides detailed spectra and particle ratios in p+p collisions and reports on nuclear modification factors and jet quenching models in Au+Au collisions at RHIC.

Findings

Measured hadron spectra up to 15 GeV/c in p+p collisions.

Reported nuclear modification factors ($R_{AA}$) for various hadrons in Au+Au collisions.

Compared $R_{AA}$ for kaons and pions, discussing jet quenching models.

Abstract

The study of hadron spectra at high $p_{T}$ in p+p collisions provides a good test of perturbative quantum chromo-dynamic calculations (pQCD) and baseline for measurements of nuclear modification factors in Au+Au collisions. Using events triggered by the Barrel Electro-Magnetic Calorimeter, identified charged hadron transverse momentum ($p_T$) spectra are measured up to 15 GeV/$c$ at mid-rapidity ($\mid y\mid$ $<$ 0.5) and neutral kaon $p_T$ spectra up to 12 GeV/$c$ in p + p collisions at $\sqrt{s_{NN}}$ = 200 GeV. The particle ratios of $p/\pi^{+}$, $\bar{p}/\pi^{-}$ and $K^{\pm,0}$ / $\pi^{\pm}$ in p + p collisions are shown and compared with next-to-leading order pQCD calculations. In central Au+Au collisions, we report nuclear modification factors ($R_{AA}$) for pion, kaon, proton and $\rho$ and discuss several model calculations: color-charge dependence of jet quenching and jet conversion. Finally, centrality dependence of $R_{AA}$ at high $p_T$ ($>$ 5.5 GeV/c) for kaon are compared with that of pion in Au + Au collisions at 200 GeV.