Bulk and shear viscosities of matter created in relativistic heavy-ion collisions

Abstract

We study the effects of shear and bulk viscosities in the hadronic phase on the expansion of the fireball and on the particle production in relativistic heavy ion collisions. Comparing simulation with or without viscosity in the hadronic matter we find that elliptic flow observables strongly dependent on dissipative effects in the late stage. On the other hand, interferometry radii are sensitive, through the early transverse flow, on the value of the viscosity at high temperatures. We present first calculations including the effects of bulk viscosity in the hadronic phase and in the hadron emission. We find them important in obtaining a small freeze-out temperature consistent with the measured transverse momentum spectra and elliptic flow of identified particles.

Triangular flow in hydrodynamics and transport theory

“…Most fluid calculations of heavy-ion collisions are done with smooth initial profiles [19][20][21][22][23]. These profiles are symmetric with respect to the reaction plane ψ R , so that all ψ n in Eq.…”

Constraining the viscous freeze-out distribution function with data obtained at the BNL Relativistic Heavy Ion Collider (RHIC)

“…First, the equations of ideal hydrodynamics were used with surprising success, indicating that the collision fireball appeared to behave like a nearly perfect liquid [1][2][3][4][5]. More recently, this ideal hydrodynamical description was generalized to viscous hydrodynamics in an effort to quantify dissipative corrections to perfect fluid behavior [6][7][8][9][10].…”

Particle spectra in Pb-Pb collisions atsNN=2.76TeV

“…Deviations from local equilibrium in the hydrodynamic model of the dynamics are introduced as viscosity corrections to the energy-momentum tensor [25][26][27][28][29][30][31][32][33][34][35]. In particular, shear viscosity is important in quantitative predictions for the elliptic and triangular collective flows.…”