ρ-MESON SPECTRAL FUNCTION IN HOT NUCLEAR MATTER

Abstract

The ρ-meson spectral function in hot nuclear matter is studied by taking into account the pion and the nucleon loops within the quantum hadrodynamics (QHD) model as well as using an effective chiral SU(3) model. The effects of density and temperature on the spectral function of the ρ-meson are studied assuming the ρ-meson to be with a finite momentum. These investigations are performed using both the mean field approximation (MFA) and the relativistic Hartree (RHA) approximation. The inclusion of the nucleon loop is observed to considerably change the ρ-meson spectral function. Due to a larger mass drop of ρ-meson in the RHA, it is seen that the spectral function shifts towards the low invariant mass region, whereas in the MFA the spectral function is seen to be almost centered around the nominal ρ-pole, but develops a second peak due to the opening of the Nh-channel. Within both the Walecka and the chiral SU(3) models, it is observed that the ρ-meson spectral function has a strong dependence on the nucleon-ρ meson tensor coupling.