Measurement of the D-meson nuclear modification factor and elliptic flow in Pb–Pb collisions at √S_NN = 5.02 TeV with ALICE at the LHC

¹ Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino Italy
² INFN sez. Torino, via Pietro Giuria 1, 10125 Torino Italy

^* e-mail: fabrizio.grosa@cern.ch

Published online: 2 February 2018

Abstract

Heavy-flavour hadrons are recognised as a powerful probe for the characterisation of the deconfined medium created in heavy-ion collisions, the Quark-Gluon Plasma (QGP). The ALICE Collaboration measured the production of D⁰, D⁺, D*⁺ and mesons in Pb–Pb collisions at = 5.02 TeV. The measurement of the nuclear modification factor (R_AA) provides a strong evidence of the in-medium parton energy loss. The comparison between the and the non-strange D-meson R_AA can help to study the hadronisation mechanism of the charm quark in the QGP. In mid-central collisions, the measurement of the D-meson elliptic flow v₂ at low transverse momentum (pT) gives insight into the participation of the charm quark into the collective motion of the system, while at high pT it constrains the path-length dependence of the energy loss. The v₂, measured for the first time at the LHC, is found to be compatible to that of non-strange D mesons and positive with a significance of about 2.6 σ. The coupling of the charm quark to the light quarks in the underlying medium is further investigated for the first time with the application of the Event-Shape Engineering (ESE) technique to D-meson elliptic flow.