Hydrodynamic radial and elliptic flow in heavy-ion collisions from AGS to LHC energies

TL;DR

This paper uses ideal hydrodynamics to analyze how radial and elliptic flow, hadron spectra, and particle ratios depend on collision energy from AGS to LHC, providing a baseline for future experiments.

Contribution

It offers the first comprehensive hydrodynamic study across a wide energy range, challenging previous ideas about elliptic flow saturation indicating the QCD phase transition.

Findings

Radial and elliptic flow increase with energy but saturate at high energies.

Differential elliptic flow v_2(p_T) does not unambiguously signal the QCD phase transition.

Provides a baseline for identifying non-equilibrium effects in LHC heavy-ion collisions.

Abstract

Using ideal relativistic hydrodynamics in 2+1 dimensions, we study the collision energy dependence of radial and elliptic flow, of the emitted hadron spectra, and of the transverse momentum dependence of several hadronic particle ratios, covering the range from Alternating Gradient Synchrotron (AGS) to Large Hadron Collider (LHC) energies. These calculations establish an ideal fluid dynamic baseline that can be used to assess non-equilibrium features manifest in future LHC heavy-ion experiments. Contrary to earlier suggestions we find that a saturation and even decrease of the differential elliptic flow v_2(p_T) with increasing collision energy cannot be unambiguously associated with the QCD phase transition.