Elliptic flow and incomplete equilibration at RHIC

Abstract

We argue that RHIC data, in particular those on the anisotropic flow coefficients v_2 and v_4, suggest that the matter produced in the early stages of nucleus-nucleus collisions is incompletely thermalized. We interpret the parameter (1/S)(dN/dy), where S is the transverse area of the collision zone and dN/dy the multiplicity density, as an indicator of the number of collisions per particle at the time when elliptic flow is established, and hence as a measure of the degree of equilibration. This number serves as a control parameter which can be varied experimentally by changing the system size, the centrality of the collision, or the beam energy. We provide predictions for Cu-Cu collisions at RHIC as well as for Pb-Pb collisions at the LHC.

5 pages, 2 figures, minor corrections

References in corpus (15)

• New Forms of QCD Matter Discovered at RHIC
• What RHIC Experiments and Theory tell us about Properties of Quark-Gluon Plasma ?
• Elliptic Flow of Identified Hadrons in Au+Au Collisions at sqrt(s_NN) = 200 GeV
• The Effect of Shear Viscosity on Spectra, Elliptic Flow, and HBT Radii
• Azimuthal anisotropy in Au+Au collisions at sqrtsNN = 200 GeV
• Saturation of Elliptic Flow and the Transport Opacity of the Gluon Plasma at RHIC
• Directed and elliptic flow of charged pions and protons in Pb+Pb collisions at 40 and 158A GeV
• Apparent Thermalization due to Plasma Instabilities in Quark-Gluon Plasma
• Hard-Loop Dynamics of Non-Abelian Plasma Instabilities
• Is early thermalization achieved only near midrapidity at RHIC ?
• Does parton saturation at high density explain hadron multiplicities at RHIC ?
• v4: A small, but sensitive observable for heavy ion collisions
• Dissipation and elliptic flow at RHIC
• Elliptic Flow from a Transversally Thermalized Fireball
• Rapidity dependent momentum anisotropy at RHIC

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