Heavy flavor relaxation in a hadronic medium

Charm and bottom transport coefficients in a medium constituted of light mesons, such as is formed in the hadronic phase of heavy-ion collisions, are obtained within an effective field theory approach implementing heavy-quark symmetry and chiral symmetry breaking. Heavy flavor propagates in the medium as D/B and D⁎/B⁎ degrees of freedom, and unitarization of the lowest order heavy-light meson amplitudes is used in order to reach high temperatures. The latter accounts for dynamically generated resonances in isospin 1/2 channels, a feature that leads to a more efficient heavy-flavor diffusion. We discuss the temperature and momentum dependence of the friction and diffusion coefficients in a transport approach up to temperatures of about T≃150MeV, and provide estimates of the charm/bottom relaxation lengths and momentum loss. Implications for heavy-meson spectrum observables in heavy-ion collisions are discussed.