Event-by-event heavy-flavour dynamics: Estimating the spatial diffusion coefficient D_s from charm to the infinite mass limit

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

Published online: 26 June 2024

Abstract

Quasi-Particle Model (QPM) has been developed to study charm quark dynamics in ultra-relativistic heavy-ion collisions with good description of D mesons R_AA(p_T) and v_2,3(p_T) and leading to the evaluation of the spatial diffusion coefficient D_s(T). With an event-by-event full Boltzmann transport approach followed by a hybrid hadronization via coalescence plus fragmentation, we show R_AA(p_T), v₂(p_T) down to p_T → 0 for D and B mesons. We find that QPM approach is able to correctly predict first available data on R_AA(p_T) and v₂(p_T) of single-electron from B mesons decays measured by ALICE. A significant breaking of the expected scaling of the thermalization time τ_th with M_Q/T is found. Charm quark D_s(T) is about 50% larger than the asymptotic value for M_Q → ∞, while the bottom D_s(T) is only 20% higher. In the infinite mass limit the D_s(T) is consistent with recent lQCD calculations with dynamical quarks.