v4 from ideal and viscous hydrodynamic simulations of nuclear collisions at the BNL Relativistic Heavy Ion Collider (RHIC) and the CERN Large Hadron Collider (LHC)

摘要

We compute v4/(v2)^2 in ideal and viscous hydrodynamics. We investigate itssensitivity to details of the hydrodynamic model and compare the results toexperimental data from RHIC. Whereas v2 has a significant sensitivity only toinitial eccentricity and viscosity while being insensitive to freeze outtemperature, we find that v4/(v2)^2 is quite insensitive to initialeccentricity. On the other hand, it can still be sensitive to shear viscosityin addition to freeze out temperature, although viscous effects do notuniversally increase v4/(v2)^2 as originally predicted. Consistent with data,we find no dependence on particle species. We also make a prediction forv4/(v2)^2 in heavy ion collisions at the LHC.