Heavy-flavour measurements in pp and Pb-Pb collisions with the ALICE experiment at the CERN LHC

TL;DR

This paper reports on the ALICE experiment's measurements of heavy-flavour hadron production in proton-proton and lead-lead collisions at the LHC, providing insights into QCD processes and quark energy loss in quark-gluon plasma.

Contribution

First systematic measurements of heavy-flavour hadron production in pp and Pb-Pb collisions at LHC energies, testing QCD and exploring quark-medium interactions.

Findings

Measured D meson and lepton production cross sections in pp collisions.

Observed nuclear modification factor R_AA indicating heavy quark energy loss.

First indications of charm quark elliptic flow in Pb-Pb collisions.

Abstract

The ALICE experiment at the CERN LHC has conducted first systematic studies of heavy-flavour hadron production in pp collisions at sqrt(s) = 7 TeV and in Pb-Pb collisions at sqrt(s_NN) = 2.76 TeV. In pp collisions the differential production cross sections of D mesons at mid-rapidity, as well as the cross sections for electrons and muons from semileptonic heavy-flavour hadron decays at mid- and forward-rapidity, respectively, have been measured. These data provide a crucial testing ground for perturbative QCD calculations in the new LHC energy regime. In Pb-Pb collisions, the nuclear modification factor R_AA(p_t) has been measured for D mesons and for leptons from heavy-flavour decays, indicating energy loss of heavy quarks in the partonic medium produced in Pb-Pb collisions at the LHC. The strong interaction of charm quarks with this medium might also generate a non-zero elliptic flow of D mesons as first studies of the azimuthal anisotropy of D^0-meson production suggest.