Relativistic mean field model with generalized derivative nucleon-meson couplings

The quantum hadrodynamics model with minimal nucleon-meson couplings is generalized by introducing couplings of mesons to derivatives of the nucleon field in the Lagrangian density. This approach allows an effective description of a state-dependent in-medium interaction in the mean-field approximation. Various parametrizations for the generalized couplings are developed and applied to infinite nuclear matter. In this approach, scalar and vector nucleon self-energies depend on both density and momentum similarly as in the Dirac-Brueckner theory. The Schrödinger-equivalent optical potential is much less repulsive at high nucleon energies as compared to standard relativistic mean-field models and thus agrees better with experimental findings. The derivative couplings in the extended model have significant effects on the properties of symmetric nuclear matter and neutron matter.