Viscosity Information from Relativistic Nuclear Collisions: How Perfect is the Fluid Observed at RHIC?
Abstract
Relativistic viscous hydrodynamic fits to Brookhaven Relativistic Heavy Ion Collider data on the centrality dependence of multiplicity, transverse, and elliptic flow for s=200GeV Au+Au collisions are presented. For standard (Glaubertype) initial conditions, while data on the integrated elliptic flow coefficient v_{2} are consistent with a ratio of viscosity over entropy density up to η/s≃0.16, data on minimum bias v_{2} seem to favor a much smaller viscosity over entropy ratio, below the bound from the anti de Sitter conformal field theory conjecture. Some caveats on this result are discussed.
 Publication:

Physical Review Letters
 Pub Date:
 October 2007
 DOI:
 10.1103/PhysRevLett.99.172301
 arXiv:
 arXiv:0706.1522
 Bibcode:
 2007PhRvL..99q2301R
 Keywords:

 25.75.q;
 12.38.Mh;
 24.10.Nz;
 25.75.Ld;
 Relativistic heavyion collisions;
 Quarkgluon plasma;
 Hydrodynamic models;
 Collective flow;
 Nuclear Theory;
 High Energy Physics  Phenomenology;
 High Energy Physics  Theory
 EPrint:
 4 pages, 5 figures