The spectral function of the omega meson in nuclear matter from a   coupled-channel resonance model
  We calculate the spectral function of the omega meson in nuclear matter at zero temperature by means of the low-density theorem. The omega N forward scattering amplitude is calculated within a unitary coupled-channel effective Lagrangian model that has been applied successfully to the combined analysis of pion- and photon-induced reactions. While the peak of the omega spectral distribution is shifted only slightly, we find a considerable broadening of the omega meson due to resonance-hole excitations. For omega mesons at rest with respect to the surrounding nuclear medium, we find an additional width of about 60 MeV at saturation density. 
P. Muehlich, V. Shklyar, S. Leupold, U. Mosel, and M. Post