Anisotropic flow of identified particles in Pb-Pb collisions at {sqrt{s}}_{mathrm{NN}}=5.02 TeV

Abstract

The elliptic (v2), triangular (v3), and quadrangular (v4) flow coefficients of π±, K±, mathrm{p}+overline{mathrm{p}},kern0.5em Lambda +overline{Lambda},kern0.5em {mathrm{K}}_{mathrm{S}}^0 , and the ϕ-meson are measured in Pb-Pb collisions at {sqrt{s}}_{mathrm{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, pT, at different collision centrality intervals between 0–70%, including ultra-central (0–1%) collisions for π±, K±, and mathrm{p}+overline{mathrm{p}} . For pT< 3 GeV/c, the flow coefficients exhibit a particle mass dependence. At intermediate transverse momenta (3 < pT < 8–10 GeV/c), particles show an approximate grouping according to their type (i.e., mesons and baryons). The ϕ-meson v2, which tests both particle mass dependence and type scaling, follows mathrm{p}+overline{mathrm{p}} v2 at low pT and π±v2 at intermediate pT. The evolution of the shape of vn(pT) as a function of centrality and harmonic number n is studied for the various particle species. Flow coefficients of π±, K±, and mathrm{p}+overline{mathrm{p}} for pT < 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 pT < 1 GeV/c. A comparison to vn coefficients measured in Pb-Pb collisions at sqrt{s_{mathrm{NN}}}=2.76 TeV is also provided.