SEMIPHENOMENOLOGICAL APPROACH TO NUCLEON PROPERTIES IN NUCLEAR-MATTER

We have evaluated the nucleon self-energy in a model that has proper analytical properties, satisfies the low density theorem and provides values of Im SIGMA for high densities comparable to those of realistic microscopic approaches. The model, however, relies only upon the NN experimental cross sections and the empirical spin-isospin interaction, which induces an important polarization of the medium. The results obtained for the spectral functions, occupation numbers, and effective masses are quite reasonable. The model does not give the absolute value of the nucleon self-energy but only differences with respect to the Fermi energy. On the other hand, it provides an easy and efficient way of evaluating many of the nucleon properties in the nuclear medium.