  Asymmetric nuclear matter is studied in the frame of relativistic mean-field
theory, using scalar-isoscalar sigma, vector-isoscalar omega meson together
with their selfinteractions, vector-isovector rho meson with its
cross-interaction with omega meson too, and scalar-isovector delta meson as
degrees of freedom. The model is used to parameterize the nuclear matter
properties results calculated by more fundamental Dirac-Brueckner-Hartree-Fock
theory and thus to provide an effective DBHF model applicable also to finite
nuclei. Vector omega-rho cross-interaction seems to be an useful degree of
freedom for describing of the asymmetric nuclear matter, mostly due to its
impact on density dependence of the symmetry energy.
