Speaker
Description
Heavy quarks (HQ) and heavy-flavored hadrons are excellent probes for studying the dynamics of high-energy nuclear collisions and the properties of the hot QCD matter therein produced. Understanding the interactions of HQ propagating through the Quark–Gluon Plasma (QGP) allows to determine its transport coefficients: the description with realistic phenomenological models of the D-meson observables, from the nuclear modification factor to the elliptic flow and higher harmonics, have led to estimate a large non-perturbative spatial diffusion coefficient of charm quarks in agreement with lattice QCD calculations within current uncertainties. In heavy-ion collisions the enhancement of the baryon to meson ratios in the heavy-flavor sector, interpreted as a signature of the QGP formation, has been explained with a quark coalescence plus fragmentation approach. This insight into the heavy-flavor hadronization processes has been recently applied also to proton-proton collisions where the charm baryon production has been found by ALICE to strongly break the universality of fragmentation functions. A coalescence approach naturally predicts such a large enhancement of baryon production ($\Lambda_c$, $\Xi_c$, $\Omega_c$) and would also predict a large multi-charm production that could be explored for the first time with ALICE3. More recently, HQs are believed to have unique roles also for probing the intense electromagnetic and vortical fields produced in ultra-relativistic heavy-ion collisions: their imprint on the D-meson directed flow is strictly connected to QGP transport properties, such as the HQ diffusion coefficient and the electric conductivity. Furthermore, the study of D-meson observables unveil characteristics of the very early stage of ultra-relativistic collisions, since the initial glasma phase may have a substantial impact on HQ propagation.
