Transport properties and elliptic flow of charm and bottom quarks in the Quark-Gluon Plasma
by Gabriele Coci (University of Catania)
at GSI ( KBW 2.27 )
Heavy Quarks (HQs), i.e. charm and bottom, play an essential role for studying the properties of the hot and dense nuclear matter, namely the Quark-Gluon Plasma (QGP), created at ultra-Relativistic Heavy-Ion Collisions (uRHICs). The two key observables in the HQ sector are the nuclear suppression factor RAA(pT) and the elliptic flow v2(pT). The theoretical challenge is to give a consistent explanation of both quantities and study the nature of their complex correlations, aiming to a solution of the so called RAA - v2 puzzle. In this seminar we will discuss about the propagation of HQs in the QGP by means of a Relativistic Boltzmann Transport approach. In this framework we account non-perturbative effects through a quasi-particle prescription where the enhancement of the strength coupling towards the critical temperature Tc is fitted to lattice QCD (lQCD) thermodynamics. This results in a HQ drag coefficient γ(T) which is almost constant near Tc. Firstly, we will present results for D meson RAA and v2 which have been widely measured both at RHIC and LHC energies. We will show that through a simultaneous description of these observables we are able to inquire about thermalization time of charm quarks estimating the spatial diffusion coefficient Ds(T) which seems in agreement with expectations from lQCD and other phenomenological models, at least within the current uncertainties. Then, we will focus on predictions for RAA and v2 of B mesons for which only preliminary data are presently available. On the other hand, investigating HQ dynamics at the bottom mass scale will reduce uncertainties coming from the adopted transport approach and will allow to estimate the Ds(T) in a regime closer to quenched lQCD.