Determination of space diffusion coefficient by heavy flavour R_AA and v_n in an event-by-event approach

¹ Department of Physics and Astronomy, University of Catania, Via S. Sofia 64, 1-95125 Catania, Italy
² Laboratori Nazionali del Sud, INFN-LNS, Via S. Sofia 62, I-95123 Catania, Italy
³ INFN Sezione di Catania, Via S. Sofia 64, 95123 Catania, Italy

^* e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.

Published online: 17 April 2026

Abstract

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 QPM_p, 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 D_s(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 R_AA(p_T) and v₂(p_T) 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.