Anisotropic flow of identified particles in Pb-Pb collisions at √sNN=5.02 TeV

Abstract

The elliptic (v_2), triangular (v_3), and quadrangular (v-4) flow coefficients of π^±, K^±, p+p¯,Λ+Λ¯,K^0_S , and the ϕ-meson are measured in Pb-Pb collisions at √s_NN=5.02 TeV. Results obtained with the scalar product method are reported for the rapidity range |y| < 0.5 as a function of transverse momentum, p_T, at different collision centrality intervals between 0–70%, including ultra-central (0–1%) collisions for π^±, K^±, and p+p¯. For p_T <3 GeV/c, the flow coefficients exhibit a particle mass dependence. At intermediate transverse momenta (3 < p_T < 8–10 GeV/c), particles show an approximate grouping according to their type (i.e., mesons and baryons). The ϕ-meson v_2, which tests both particle mass dependence and type scaling, follows p+p¯ v_2 at low p_T and π^± v_2 at intermediate p_T. The evolution of the shape of v_n(p_T) as a function of centrality and harmonic number n is studied for the various particle species. Flow coefficients of π^±, K^±, and p+p¯ for p_T 3 GeV/c are compared to iEBE-VISHNU and MUSIC hydrodynamical calculations coupled to a hadronic cascade model (UrQMD). The iEBE-VISHNU calculations describe the results fairly well for pT < 2.5 GeV/c, while MUSIC calculations reproduce the measurements for p_T < 1 GeV/c. A comparison to v_n coefficients measured in Pb-Pb collisions at √s_NN=2.76 TeV is also provided.