Determination of space diffusion coefficient by heavy flavour

The strong interaction in the non-perturbative regime typical of the system created in heavy-ion collisions has been studied in the past years through an effective Quasi-Particle Model (QPM). Recently, an extension to a more realistic model named QPMp, which incorporates momentum-dependent parton masses as entailed by QCD asymptotic free dynamics, leads to a good agreement with the lQCD quark susceptibilities previously underestimated in the simple QPM. A main general result is that for charm quarks the extracted space diffusion Ds(T) appears to be significantly larger (about 40 – 50 %) wrt the recent lQCD data. Within an event-by-event transport approach based on Langevin equations, we evaluate RAA(pT) and v2(pT) for D mesons in PbPb at 5 TeV. We propose a novel analysis that point out the crucial role of the momentum dependence of the interaction to draw solid conclusions about the agreement between the phenomenological approach and lattice QCD calculation as well as to determine the thermalization time of heavy quarks.