Anisotropic flow of identified particles in Pb–Pb collisions at √s_NN= 2.76 TeV measured with ALICE at the LHC

Abstract

Abstract. The anisotropic flow (v n ) of identified particles is an important observable to probe the freeze-out properties, the parton energy loss and the transport coefficients of the system created in heavy-ion collisions. We report on the anisotropic flow measurements for a number of identified particles such as charged pions, kaons and (anti-)protons, as well as K 0The measurements are performed in the rapidity range |y| < 0.5, over a wide range of transverse momenta, 0.2 < p T < 6 GeV/c, for Pb-Pb collisions at √ s NN = 2.76 TeV recorded by ALICE at the LHC. We will present the mass ordering as a function of transverse momentum for several collision centralities compared with results al lower energies. While in the low p T region hydrodynamical computations describe the experimental data points fairly well, at intermediate momenta the quark number (n q ) scaling indicates that it holds at an approximate level of 20-30%. Finally, focusing on the low momentum region ALICE has recently observed a similar mass ordering behaviour of v 2 in p-Pb systems. We will present this intriguing result which may be connected to a collective effect similar to that observed in Pb-Pb collisions.

A unified description of the reaction dynamics from pp to pA to AA collisions

“…Finally, one can combine the power of dihadron correlations and particle identification: The mass effect discussed above for particle spectra, is also very clearly visible in correlations, leading to the so-called mass-splitting in the elliptical flow coefficient v 2 as a function of p t , as shown in fig. 3, where we plot v 2 for different hadrons for Pb-Pb (right plot, [8]) and p-Pb (left plot, [9]). In both cases, one can clearly see the separation of particles of different masses.…”