Heavy-flavour production in Pb-Pb collisions at $\sqrt{s_{NN}}$ = 2.76 TeV with the ALICE detector

TL;DR

This paper discusses measurements of heavy-flavour hadron production in Pb-Pb collisions at 2.76 TeV using the ALICE detector, focusing on nuclear modification factors and elliptic flow to probe the QCD medium properties.

Contribution

It presents new experimental results on heavy-flavour hadron suppression and flow in heavy-ion collisions at LHC energies, providing insights into quark energy loss and medium thermalization.

Findings

Heavy-flavour hadrons show suppression in Pb-Pb collisions compared to pp.

Elliptic flow measurements indicate partial thermalization of charm quarks.

Results are consistent with models of in-medium energy loss and QCD medium properties.

Abstract

Hadrons containing heavy-flavours, i.e. charm and beauty quarks, are unique probes of the properties of the hot and dense QCD medium produced in heavy-ion collisions. Due to their large masses, heavy quarks are produced at the initial stage of the collision, almost exclusively via hard partonic scattering processes. Therefore, they are expected to experience the full collision history propagating through and interacting with the QCD medium. The parton energy loss, which is sensitive to the transport coefficients of the produced medium, can be studied experimentally by measuring the nuclear modication factor ($R_{\rm AA}$) which accounts for the modication of the heavy-flavoured hadron yield in Pb-Pb collisions with respect to pp collisions. In semi-central Pb-Pb collisions, the degree of thermalization of charm quarks in the QCD medium can be accessed via the measurement of the heavy flavour elliptic flow $v_2$ at low $p_{\rm T}$ . At high $p_{\rm T}$, $v_2$ is sensitive to the path-length dependence of heavy quark in-medium energy loss. The ALICE collaboration has measured the production of open heavy flavour hadrons via their hadronic and semi-leptonic decays at mid-rapidity and in the semi-muonic decay channel at forward rapidity in pp, p-Pb and Pb-Pb collisions at 7, 5.02 and 2.76 TeV respectively. In this talk the current results on open heavy-flavour $R_{\rm AA}$ and $v_2$ will be presented.