$\rho$ self energy at finite temperature and density in the real-time formalism

Abstract

The $\rho$ meson self-energy in nuclear matter from baryonic loops is analysed in the real time formulation of field theory at finite temperature and density. The discontinuities across the branch cuts of the self-energy function are evaluated for an exhaustive set of resonances in the loops considering the fully relativistic thermal baryon propagator including anti-baryons. Numerical calculations show a significant broadening of the $\rho$ spectral function coming from the Landau cut. Adding the contribution from mesonic loops, the full spectral function of the $\rho$ in a thermal gas of mesons, baryons and antibaryons in equilibrium is evaluated at various values of temperature and baryonic chemical potential.