Single-particle magnetic moments in a relativistic shell model

Starting from the original σ + ω model of Walecka, single-particle properties of finite nuclei are derived in the Dirac-Hartree approximation. In such a model, large relativistic corrections are found for the single-particle Dirac magnetic moment, whose origin is found to be closely connected with the effective nucleon mass in nuclei yielding a reasonable value of the spin-orbit splitting. A phenomenological model, which takes into account tensor as well as space-like vector potentials, is found to reduce considerably the amount of relativistic corrections. A possible connection with the Dirac-Hartree-Fock approximation is discussed.