Anisotropic flow of identified particles in Pb-Pb collisions at {formula}= 2.76 TeV measured with ALICE at the LHC

摘要

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 {formula}, and {formula}. The 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 {formula}= 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.