Higher flow harmonics from (3+1)D event-by-event viscous hydrodynamics

TL;DR

This paper uses event-by-event viscous hydrodynamics to analyze flow harmonics in heavy-ion collisions at RHIC, revealing their dependence on initial state and shear viscosity, and suggesting a low eta/s for the quark-gluon plasma.

Contribution

It provides a detailed viscous hydrodynamic model that links flow harmonics to initial conditions and viscosity, enabling precise eta/s determination from experimental data.

Findings

Higher flow harmonics strongly depend on initial granularity and shear viscosity.

Results suggest eta/s_QGP < 2/4pi at RHIC.

Viscosity influences pseudo-rapidity spectra and transverse momentum distributions.

Abstract

We present event-by-event viscous hydrodynamic calculations of the anisotropic flow coefficients v_2 to v_5 for heavy-ion collisions at the Relativistic Heavy-Ion Collider (RHIC). We study the dependence of different flow harmonics on shear viscosity and the morphology of the initial state. v_3 and higher flow harmonics exhibit a particularly strong dependence on both the initial granularity and shear viscosity. We argue that a combined analysis of all available flow harmonics will allow to determine eta/s of the quark gluon plasma precisely. Presented results strongly hint at a value (eta/s)_QGP < 2/4pi at RHIC. Furthermore, we demonstrate the effect of shear viscosity on pseudo-rapidity spectra and the mean transverse momentum as a function of rapidity.