Relativistic Few Body Calculations

A modern treatment of the nuclear few-body problem must take into account both the quark structure of baryons and mesons, which should be important at short range, and the relativistic exchange of mesons, which describes the long range, peripheral interactions.A way to model both of these aspects is described.The long range, peripheral interactions are calculated using the spectator model, a general approach in which the spectators to nucleon interactions are put on their mass-shell. Recent numerical results for a relativistic OBE model of the NN interaction, obtained by solving a relativistic equation with one-particle on mass-shell, will be presented and discussed.Two meson exchange models, one with only four mesons (pi, sigma, rho, omega) but with a 25% admixture of gamma^5 coupling for the pion, and a second with six mesons (pi, sigma, rho, omega, delta, eta) but pure gamma^5 gamma^micro pion coupling, are shown to give very good quantitative fits to the NN scattering phase