Rapid hydrodynamic expansion in relativistic heavy-ion collisions

TL;DR

This paper models the hydrodynamic expansion of hot matter in relativistic heavy-ion collisions, successfully describing various experimental observables and indicating early collective behavior with high initial energy density.

Contribution

It provides a comprehensive 3+1D hydrodynamic model that matches experimental data and constrains initial conditions in relativistic heavy-ion collisions.

Findings

Successful description of spectra, flow, and radii across centralities and rapidities.

Evidence for early onset of collectivity in the collision dynamics.

High initial energy density at the fireball center.

Abstract

Hydrodynamic expansion of the hot fireball created in relativistic Au-Au collisions at 200GeV in 3+1-dimensions is studied. We obtain a simultaneous, satisfactory description of the transverse momentum spectra, elliptic flow and pion correlation radii for different collision centralities and different rapidities. Early initial time of the evolution is required to reproduce the interferometry data, which provides a strong indication of the early onset of collectivity. We can also constraint the shape of the initial energy density in the beam direction, with a relatively high initial energy density at the center of the fireball.