Indications of early thermalization in relativistic heavy-ion collisions

Abstract

The directed flow of particles emitted from the fireball created in a heavy-ion collision is shown to be a very sensitive measure of the pressure equilibration in the first 1 fm/c of the evolution. Performing a 3+1 dimensional relativistic hydrodynamic calculation with nonequilibrated longitudinal and transverse pressures, we show that the directed flow is strongly reduced if the pressure imbalance survives for even a short time. Transverse momentum spectra, elliptic flow and interferometry correlation radii are not very sensitive to this early pressure anisotropy. Comparison with the data points toward a short equilibration time of the order of $0.25$fm/c or less.

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Cited by in corpus (9)

• Highly-anisotropic hydrodynamics in 3+1 space-time dimensions
• Plasmons in Anisotropic Quark-Gluon Plasma
• Splitting of proton-antiproton directed flow in relativistic heavy-ion collisions
• Event-by-event viscous hydrodynamics for Cu-Au collisions at 200GeV
• Interplay of longitudinal and transverse expansion in the kinetic dynamics of heavy-ion collisions
• Collective phenomena in the early stages of relativistic heavy-ion collisions
• Anisotropy effects on heavy quark dynamics in Gribov modified gluon plasma
• Collective excitations in the hot QCD medium and the propagation of Heavy Quarks
• The early thermalization and HBT puzzles at RHIC