Seminario de Física-Matemática

Abstract:

Suppression of open heavy flavors and quarkonia in heavy-ion collisions is among the most informative probes of the quark-gluon plasma. Interpreting the full wealth of data obtained from the collision events requires a precise understanding of the evolution of heavy quarks and quarkonia as they propagate through the nearly thermal and strongly coupled plasma. Only in the past few years, systematic theoretical studies of quarkonium time evolution in the QGP have been carried out in the regime where the temperature of the QGP is much smaller than the inverse of quarkonium size. Understanding the dynamics of heavy particle pairs in a thermal plasma in the analogous regime is also relevant to assess bound state effects on the dark matter thermal relic abundance in colored co-annihilation scenarios.

Such calculations require the evaluation of a gauge-invariant correlator of chromoelectric fields dressed with Wilson lines, which is similar to, but different from, the correlation used to define the well-known heavy quark diffusion coefficient. In this talk, we will describe its calculation at weak coupling in QCD up to next-to-leading order and at strong coupling in N=4 SYM using the AdS/CFT correspondence. At first sight, the calculations are similar to those of the open heavy quark case, but a closer inspection reveals that they have crucial differences that highlight the relevance of quantum color correlations. Crucial insights are obtained by studying them in temporal axial gauge, where these correlators would naively be equal. Finally, we give a prescription to evaluate this correlation function from lattice QCD, which, at present, is the only tool we have to study QCD in the non-perturbative regime.