Vector and axial-vector mesons at nonzero temperature within a gauged linear sigma model

We consider vector and axial-vector mesons in the framework of a gauged linear sigma model with chiral U(Nf)R×U(Nf)L symmetry. For Nf=2, we investigate the behavior of the chiral condensate and the meson masses as a function of temperature by solving a system of coupled Dyson-Schwinger equations derived via the 2PI formalism in double-bubble approximation. We find that the inclusion of vector and axial-vector mesons tends to sharpen the chiral transition. Within our approximation scheme, the mass of the ρ meson increases by about 100 MeV towards the chiral transition.