Forward-rapidity azimuthal and radial flow of identified particles for $\sqrt{s_{NN}}$ = 200 GeV Au+Au collisions

TL;DR

This paper measures the azimuthal flow of identified particles in gold-gold collisions at 200 GeV to understand the system's rapid equilibration and flow behavior across different pseudorapidities.

Contribution

It provides detailed measurements of $v_2$ for pions, kaons, and protons as functions of $p_T$, centrality, and pseudorapidity, extending understanding of flow dynamics at RHIC.

Findings

Flow signals are strong at forward rapidities.

Constituent quark scaling is observed across pseudorapidities.

Hydrodynamic models describe the flow behavior well.

Abstract

A strong azimuthal flow signature at RHIC suggests rapid system equilibration leading to an almost perfect fluid state. The longitudinal extent of the flow behavior depends on how this state is formed and can be studied by measuring the pseudorapidity and transverse momentum dependence of the second Fourier component ($v_{2}(p_{T})$) of the azimuthal angular distribution. We report on a measurement of identified-particle $v_{2}$ as a function of $p_{T}$ (0.5-2.0 GeV/c), centrality (0-25%, 25-50%), and pseudorapidity ($0\leq\eta<3.2$) for $\sqrt{s_{NN}} = 200 \rm GeV$ Au+Au collisions. The BRAHMS spectrometers are used for particle identification ($\pi$, K, p) and momentum determination and the BRAHMS global detectors are used to determine the corresponding reaction-plane angles. The results are discussed in terms of the rapidity dependence of constituent quark scaling and in terms of models that develop the complete (azimuthal and radial) hydrodynamic aspects of the forward dynamics at RHIC.