Scalar and vector meson propagation in asymmetric nuclear matter

The propagation of the scalar (\sigma and \delta) and vector (\omega and \rho) mesons in an iso-asymmetric nuclear matter is studied in detail, using the Walecka model. We calculate the invariant masses and spectral functions of the mesons, including the effect of meson mixing. At finite density, the mixing effect is quite important in the propagation of the scalar and (longitudinal) vector mesons. In the \sigma channel, we find a three-peak structure in the spectral function, caused by the mixing effect.