Systematic Studies of Elliptic Flow Measurements in Au+Au Collisions at sqrt(s_NN) = 200 GeV

TL;DR

This study measures elliptic flow of charged hadrons in gold-gold collisions at 200 GeV, comparing different analysis methods to understand non-flow effects and flow fluctuations across various collision centralities and transverse momenta.

Contribution

It provides a comprehensive comparison of event plane and cumulant methods for elliptic flow measurement in heavy-ion collisions at RHIC.

Findings

Event plane results are consistent within uncertainties for most conditions.

Maximum 20% difference observed between methods in peripheral collisions.

Insights into non-flow effects and flow fluctuations across centralities and p_T ranges.

Abstract

We present inclusive charged hadron elliptic flow v_2 measured over the pseudorapidity range |\eta| < 0.35 in Au+Au collisions at sqrt(s_NN) = 200 GeV. Results for v_2 are presented over a broad range of transverse momentum (p_T = 0.2-8.0 GeV/c) and centrality (0-60%). In order to study non-flow effects that are not correlated with the reaction plane, as well as the fluctuations of v_2, we compare two different analysis methods: (1) event plane method from two independent sub-detectors at forward (|\eta| = 3.1-3.9) and beam (|\eta| > 6.5) pseudorapidities and (2) two-particle cumulant method extracted using correlations between particles detected at midrapidity. The two event-plane results are consistent within systematic uncertainties over the measured p_T and in centrality 0-40%. There is at most 20% difference of the v_2 between the two event plane methods in peripheral (40-60%) collisions. The comparisons between the two-particle cumulant results and the standard event plane measurements are discussed.