Off-shell behavior of nucleon self-energy in asymmetric nuclear matter

The off-shell behavior of the nucleon self-energy in isospin-asymmetric nuclear matter is investigated within the framework of the relativistic Dirac-Brueckner-Hartree-Fock approach based on projection techniques. The dependence of the Dirac components of the self-energy on momentum as well as energy is evaluated for symmetric as well as asymmetric nuclear matter. Special attention is paid to the various contributions to the momentum dependence of the real and imaginary part of the optical potential. The consequences to the different definitions of the effective nucleon mass and particle spectral functions are discussed.