Systematic studies of elliptic flow measurements in Au+Au collisions at sNN=200 GeV

Abstract

We present inclusive charged hadron elliptic flow (v2) measured over the pseudorapidity range |η|<0.35 in Au+Au collisions at sNN=200 GeV. Results for v2 are presented over a broad range of transverse momentum (pT=0.2-8.0 GeV/c) and centrality (0-60%). To study nonflow effects that are correlations other than collective flow, as well as the fluctuations of v2, we compare two different analysis methods: (1) the event-plane method from two independent subdetectors at forward (|η|=3.1-3.9) and beam (|η|>6.5) pseudorapidities and (2) the 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 pT and in centrality 0-40%. There is at most a 20% difference in the v2 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. © 2009 The American Physical Society.