Aspects of meson properties in dense nuclear matter

We investigate the modification of meson spectral densities in dense nuclear matter at zero temperature. These effects are studied in a fully relativistic mean field model which goes beyond the linear density approximation and also includes baryon resonances. In particular, the role of N*(1520) and N*(1720) on the ρ meson spectral density is highlighted. Even though the nucleon-nucleon loop and the nucleon-resonance loop contribute with the opposite sign, an overall reduction of ρ meson mass is still observed at high density. Importantly, it is shown that the resonances cause substantial broadening of the ρ meson spectral density in matter and also induce nontrivial momentum dependence. We study the dispersion relations and collective oscillations induced by the ρ meson propagation in nuclear matter together with the influence of the mixing of ρ with the a0 meson. The relevant expression for the plasma frequency is also recovered analytically in the appropriate limit. The spectral density of the a0 meson is also shown