Are eccentricity fluctuations able to explain the centrality dependence of $v_4$?

Abstract

The fourth harmonic of the azimuthal distribution of particles $v_4$ has been measured for Au-Au collisions at the Relativistic Heavy Ion Collider (RHIC). The centrality dependence of $v_4$ does not agree with the prediction from hydrodynamics. In particular, the ratio $v_4/(v_2{)}^2$, where $v_2$ denotes the second harmonic of the azimuthal distribution of particles, is significantly larger than predicted by hydrodynamics. We argue that this discrepancy is mostly due to elliptic flow ($v_2$) fluctuations. We evaluate these fluctuations on the basis of a Monte Carlo Glauber calculation. The effect of deviations from local thermal equilibrium is also studied, but appears to be only a small correction. Combining these two effects allows us to reproduce experimental data for peripheral and midcentral collisions. However, we are unable to explain the large magnitude of $v_4/(v_2{)}^2$ observed for the most central collisions.

talk presented at the Strangeness in Quark Matter Conference, Buzios, Brazil, Sept. 27 - oct. 2, 2009

References in corpus (5)

• Centrality dependence of charged hadron and strange hadron elliptic flow from sqrt(s_NN) = 200 GeV Au+Au collisions
• The centrality dependence of elliptic flow, the hydrodynamic limit, and the viscosity of hot QCD
• Effect of flow fluctuations and nonflow on elliptic flow methods
• Momentum spectra, anisotropic flow, and ideal fluids
• Effects of flow fluctuations and partial thermalization on $v_4$

Cited by in corpus (1)

• Understanding anisotropy generated by fluctuations in heavy-ion collisions