Mass of ω meson in the nuclear matter

General symmetry arguments (the sum QCD rules) predict that the effective mass of the ω and σ mesons in the nuclear matter must diminish as against their free space values, when the baryonic density increases. It seems interesting to study the modifications of the meson masses in a baryonic medium by explicitly calculation of the poles (in the like-time region) of the dressed meson propagations. Since the mesons can be coupled to nucleons by polarization processes i.e. by density fluctuations, their masses must be sensible to the nuclear matter compressibility. Actually, by using the relativistic Hartree approximation which overestimates the incompressibility module (K = 500 MeV), we have obtained an ω meson mass value which decreases practically linearly with the density as against its free value. In contradistinction, by using for this calculation a density-dependent relativistic NN interaction, as given by a Dirac-Brueckner model, which reproduces correctly the nuclear matter compressibility (K = 250 MeV), we have equally observed a decrease in the ω meson mass in the nuclear environment.But this mass appears to be constant, independently of the density value as long as it is higher than 20% of saturation density. Experiments of determining the ω mass should be soon realized at TJNAF (late CEBAF) and these are expected to show at which extent our description is realistic