Publication : t09/245
Are eccentricity fluctuations able to explain the centrality dependence of v_4 ?
Gombeaud C. (CEA, IPhT (Institut de Physique Théorique), F-91191 Gif-sur-Yvette, France)Ollitrault J.-Y. (CEA, IPhT (Institut de Physique Théorique), F-91191 Gif-sur-Yvette, France)
Abstract:Année de publication : 2010
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.
Revue : J. Phys. G 37 094024 (2010)
Conférence - Communication invitée : par Gombeaud C.; International Conference on Strangeness in Quark Matter (SQM09) ; Buzios, Brasil ; 2009-09-27 / 2009-10-02
DOI : 10.1088/0954-3899/37/9/094024
Preprint : arXiv:0912.3623
Langue : Anglais
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