Anisotropic flow in sqrt(s)=2.76 TeV Pb+Pb collisions at the LHC

TL;DR

This paper reports that elliptic flow measurements in Pb+Pb collisions at 2.76 TeV are similar to those at lower energies, supporting the idea of a nearly perfect liquid produced in heavy-ion collisions at the LHC.

Contribution

It demonstrates that elliptic flow at LHC and RHIC energies is consistent with viscous hydrodynamic models and provides predictions for triangular flow.

Findings

Elliptic flow is similar at LHC and RHIC energies.

Elliptic flow develops mostly within the first 5 fm/c of collision.

Results support the creation of an almost perfect liquid in LHC collisions.

Abstract

The results on elliptic flow in sqrt(s)=2.76 TeV Pb+Pb collisions at the Large Hadron Collider (LHC) reported by the ALICE collaboration are remarkably similar to those for sqrt(s)=200 GeV gold-gold collisions at the Relativistic Heavy Ion Collider (RHIC). This result is surprising, given the expected longer lifetime of the system at the higher collision energies. We show that it is nevertheless consistent with 3+1 dimensional viscous event-by-event hydrodynamic calculations, and demonstrate that elliptic flow at both RHIC and LHC is built up mostly within the first 5 fm/c of the evolution. We conclude that an "almost perfect liquid" is produced in heavy-ion collisions at the LHC. Furthermore, we present predictions for triangular flow as a function of transverse momentum for different centralities.