Properties of the $\omega$ Meson at Finite Temperature and Density
  The mass shift, width broadening, and spectral density for the $\omega$ meson in a heat bath of nucleons and pions is calculated using a general formula which relates the self-energy to the forward scattering amplitude. We use experimental data to saturate the scattering amplitude at low energies with resonances and include a background Pomeron term, while at high energies a Regge parameterization is used. The peak of the spectral density is little shifted from its vacuum position, but the width is considerably increased due to collisional broadening. At normal nuclear matter density and a temperature of 150 MeV the spectral density of the $\omega$ meson has a width of 140 MeV. Zero temperature nuclear matter is also discussed. 
A. T. Martell and P. J. Ellis