High-momentum components in a relativistic mean-field ground state.

Abstract

We have calculated nucleon spectral functions and momentum distributions for $^{16}\mathrm{O}$ and infinite nuclear matter in a relativistic mean-field approximation to the Walecka model. In spite of the mean-field nature of the ground state we have observed fragmentation of single-particle strength and partial occupancy of single-particle orbits. A substantial amount of single-particle strength was found at very high excitation energy due to particle-antiparticle mixing. This mixing was also responsible for the high-momentum tail seen in the calculation of nucleon momentum distributions. We argued that these findings are a general consequence of the relativistic formalism and should remain valid even in more sophisticated treatments of the ground state.