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Issue Eur. Phys. J. C Volume 62, Number 1, July 2009 Hot Quarks 2008 Page(s) 169 - 173 Section Regular Article - Experimental Physics DOI 10.1140/epjc/s10052-009-1019-x Published online 08 April 2009

Eur. Phys. J. C 62, 169-173 (2009)
DOI: 10.1140/epjc/s10052-009-1019-x

Centrality dependence of v ₂ in Au + Au at  GeV

Unidentified charged hadron v ₂ with respect to the first harmonic ZDC-SMD event plane

Hiroshi Masui

Nuclear Science Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA, 94720, USA

HMasui@lbl.gov

Received 30 September 2008 / Revised version 7 February 2009 / Published online 8 April 2009

Abstract

One of the most striking results is the large elliptic flow (v ₂) at RHIC. Detailed mass and transverse momentum dependence of elliptic flow are well described by ideal hydrodynamic calculations for p _T<1 GeV/c, and by parton coalescence/recombination picture for p _T=2–6 GeV/c. The systematic error on v ₂ is dominated by so-called “non-flow effects”, which are correlations other than flow, such as resonance decays and jets. It is crucial to understand and reduce the systematic error from non-flow effects in order to understand the underlying collision dynamics. In this paper, we present the centrality dependence of v ₂ with respect to the first harmonic event plane at ZDC-SMD (v ₂) in Au + Au collisions at  GeV. A large rapidity gap (|Δη|>6) between midrapidity and the ZDC-SMD could enable us to minimize possible non-flow contributions. We compare the results of v ₂ with v ₂, which is measured by event plane determined at |η|=3.1–3.9. Possible non-flow contributions in those results will be discussed.

PACS
25.75.-q
25.75.Ld

Correspondence: HMasui@lbl.gov


© Società Italiana di Fisica, Springer-Verlag 2009

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