Elliptic flow in Pb+Pb collisions at sqrt{s_{NN}} = 2.76 TeV: hybrid model assessment of the first data

TL;DR

This study uses a hybrid model combining hydrodynamics and hadron cascade to analyze elliptic flow in heavy-ion collisions at different energies, revealing that differential flow remains stable while integrated flow increases with energy.

Contribution

It assesses the impact of initial condition models on elliptic flow predictions using a hybrid approach at different collision energies.

Findings

Differential v_2(p_T) is stable across energies.

Integrated v_2 increases with collision energy.

The initial condition model significantly influences flow results.

Abstract

We analyze the elliptic flow parameter v_2 in Pb+Pb collisions at sqrt{s_{NN}} = 2.76 TeV and in Au+Au collisions at sqrt{s_{NN}} =200 GeV using a hybrid model in which the evolution of the quark gluon plasma is described by ideal hydrodynamics with a state-of-the-art lattice QCD equation of state, and the subsequent hadronic stage by a hadron cascade model. For initial conditions, we employ Monte-Carlo versions of the Glauber and the Kharzeev-Levin-Nardi models and compare results with each other. We demonstrate that the differential elliptic flow v_2(p_T) hardly changes when the collision energy increases, whereas the integrated v_2 increases due to the enhancement of mean transverse momentum. The amount of increase of both v_2 and mean p_T depends significantly on the model of initialization.