σ and ω meson propagation in a dense nuclear medium

The propagation of the scaler (sigma) and vector (omega) mesons in nuclear matter is studied in detail using the Walecka model over a wide range of densities and including the effects of a finite sigma width through the inclusion of a two-pion loop. We calculate the dispersion relation and spectral functions of the sigma and (transverse and longitudinal) omega mesons, including the effect of sigma-omega mixing in matter. It is shown that the mixing effect is quite important in the propagation of the (longitudinal) omega and sigma mesons above normal nuclear matter density. We find that there is a two-peak structure in the spectral function of the sigma channel, caused by sigma-omega mixing. (C) 1998 Elsevier Science B.V. All rights reserved.