Coefficienti di trasporto per mesoni charmati in un gas di adroni leggeri

This work fits into the wide research field devoted to the study of Quark Gluon Plasma (QGP), currently at the center of a vivid theoretical and experimental activity. During the last years, a rich amount of experimental data have become available from high-energy nuclear collisions, both at RHIC and at LHC. A deeper and deeper understanding of such data is actually one of the main goals of the theoretical research in Quantum Chromodynamics (QCD) in the high temperature/density regime. Transport models have a decisive importance in characterizing the properties of the plasma phase of QCD supposed to be formed in heavy-ion collisions. They represent a convenient tool to simulate the propagation in the medium of heavy-flavour particles, the latter being one of the most powerful available probes to characterize the QGP. Post-hadronization effects (i.e. the dynamics in the hadron gas following the quark-hadron transition) on the final spectra of such heavy particles (open charm/beauty states and their decay products) are often neglected in literature, even if it is not clear at the moment whether this could be a good approximation or not. This is the issue we decide to address. We then present results for the transport coefficients of charmed mesons propagating through the hot hadron gas formed in the final stage of heavy-ion collisions. Our results are conceived to be eventually plugged into numerical transport simulations. Our exposition is organized as follows. We will first illustrate some of the main features concerning the physics of the QGP and heavy-ion collisions, in order to clarify the general framework and the state of the art of the field. A rapid sketch of transport theory is presented, as well as the fundamental theoretical basis of strong interactions. Then, using a chirally invariant lagrangian, scattering amplitudes in the case of 2 light flavours are computed. Finally, results for the momentum and temperature dependence of the transport coefficients are shown.