Eur. Phys. J. Plus (2016) 131: 366
https://doi.org/10.1140/epjp/i2016-16366-1

Regular Article

Measurement of D⁰-meson production in Pb-Pb and p-Pb collisions with the ALICE experiment at the LHC

¹ Univesità degli Studi di Padova, Padova, Italy
² INFN, Sezione di Padova, Padova, Italy

^* e-mail: andrea.festanti@pd.infn.it

Received: 31 May 2016
Accepted: 11 September 2016
Published online: 19 October 2016

Abstract

In this article, a review of the measurements of the production of prompt charmed D⁰ mesons relative to the reaction plane in Pb-Pb collisions at the centre-of-mass energy per nucleon-nucleon collision of TeV, and of the D⁰ production in p-Pb collisions at TeV with the ALICE experiment at the CERN Large Hadron Collider is presented. The azimuthal anisotropy is quantified via the second coefficient v₂ in a Fourier expansion of the D⁰ azimuthal distribution, and the nuclear modification factor , measured with respect to the reaction plane. The D⁰ production is measured in both systems by reconstructing the two-prong hadronic decay in the central rapidity region. A positive elliptic flow is observed in Pb-Pb collisions in the centrality class 30-50%, with a mean value of in the interval GeV/c, which decreases towards more central collisions. Consequently, the nuclear modification factor shows a stronger suppression in the direction orthogonal to the reaction plane. The D⁰ nuclear modification factor in p-Pb collisions is compatible with unity within uncertainties. The multiplicity dependence of the D⁰ production is also studied by comparing yields in p-Pb collisions in four event classes with those in pp collisions, scaled by the number of binary nucleon-nucleon collisions, as well as by evaluating the yields per event in multiplicity intervals normalised to the multiplicity-integrated ones. The nuclear modification factor is consistent with unity in the four considered event classes, within uncertainties. The relative D⁰-meson yields increase as a function of the charged-particle multiplicity. The Pb-Pb and p-Pb results are compared to theoretical calculations of charm quark transport and energy loss in high-density strongly interacting matter at high temperature and including initial-state effects induced by the nuclear environment, respectively.