Relativistic effects in nuclear physics

Abstract

Relativistic corrections to the nonrelativistic nuclear many‐body problem are treated in perturbation theory, beginning from a zero‐order wave function in which nucleons are in positive energy states in a plane‐wave representation. Corrections arise from virtual pairs. Two important relativistic effects arise: (1) A repulsive term in the energy per particle (δε̄)rel=2.4(ρ/ρ0)8/3 MeV, where ρ0 is nuclear matter density, comes from the virtual pair terms. This term can equivalently be viewed as coming from a density‐dependent correction to the mass of the exchanged scalar boson. (2) The nucleon‐nucleon spin‐orbit interaction is modified. Effectively, the nucleon mass which enters into this interaction is changed locally by scalar fields which connect to virtual pair states.When treated consistently, relativistic effects represent small corrections to the nonrelativistic many‐body problem, and can easily be grafted on to the latter. In this way one can exploit the nonrelativistic many‐body calculations, which have been carried out with much more detailed and sophisticated treatment of correlations than in the relativistic formulation.In high‐energy reactions, which are treated only briefly here, the modification of the spin‐orbit term has important consequences.