Heavy Quarkonium Transport and Transport Coefficients

Abstract: Due to their large masses and short formation times, heavy quarkonium states are ideal probes of the medium formed in heavy ion collisions.  Three processes determine the evolution of these states in medium: dissociation of color-singlet states into color-octet pairs, the inverse recombination process and transitions of quark-antiquark pairs between different color-octet states.  In this talk, I will present a diagrammatic derivation of the in-medium master equation of heavy quarkonium taking explicit account of the color state of the medium relevant when considering octet-singlet and octet-octet transitions.  To each of the three processes is associated a distinct correlator of two chromoelectric fields differing in color flow, i.e., in the configuration of the Wilson lines connecting the chromoelectric fields.  The moments of these chromoelectric correlators correspond to coefficients in an expansion in the binding energy of the quarkonium state over the thermal scale of the medium and are related to heavy quarkonium transport coefficients.  Additionally, I will discuss conditions under which the master equation can be brought into a form amenable to numerical solution and observables including the nuclear modification factor and elliptic flow calculated and compared against experimental measurements.