Higher harmonic anisotropic flow of identified particles in Pb–Pb collisions with the ALICE detector

Abstract

Anisotropic flow plays a crucial role in establishing the equation of state of the Quark Gluon Plasma. The results at RHIC and LHC have demonstrated that the matter created in heavy-ion collisions behaves as a nearly perfect fluid reflected in the low value of the shear viscosity over entropy density ratio (η/s). The higher flow harmonics are particularly sensitive to the value of η/s in hydrodynamic calculations. In this analysis, we present the first ALICE results on the p T differential v 2 , v 3 and v 4 for π ± , K ± , p(p) from the high statistics 2011 heavy-ion run. We investigate how these v n coefficients evolve with particle mass and centrality for the 0-1% and 20-30% centrality ranges. These new measurements aim at differentiating between models that use different initial conditions, constraining further the value of η/s and allowing to decouple the influence of the late hadronic stage from the hydrodynamic evolution of the system.

Collective flow and hydrodynamics in large and small systems at the LHC

“…(Color online) v n (p T ) (n = 2, 3, 4) of pions, kaons and protons in 2.76 A TeV Pb-Pb collisions, calculated from iEBE-VISHNU with AMPT initial conditions[109]. The experimental data are taken from the ALICE paper[153,154].…”