Relativistic effects in the Bethe-Brueckner theory of nuclear matter

Abstract

We extend the theory of nuclear matter to include a relativistic description of nucleon motion. In particular we allow for negative energy components in the nucleon wave function. The amplitude for these components is calculated using an extended version of the one-boson-exchange model of nuclear forces. We find that the inclusion of negative energy states (pair currents) provides a strongly density dependent repulsive interaction. (If one limits oneself to a description involving positive energy states only, this interaction appears as an effective repulsive many-body force.) Our extended theory leads to major modification of the saturation properties of nuclear matter. For example, a boson-exchange force which, in a standard calculation, leads to significant overbinding of nuclear matter at much too high a saturation density yields, in our relativistic analysis, quite good agreement with the generally accepted empirical values for the binding energy and density of nuclear matter. (This potential has strong tensor coupling for the $\ensuremath{\rho}$ meson and a weak tensor force. These features are favored at this time on the basis of other theoretical considerations.) We conclude that, contrary to current thought, nuclear matter should be treated as a relativistic system.NUCLEAR STRUCTURE Relativistic effects in the saturation properties of nuclear matter.