Relativistic Treatment of Low-Energy Nucleon-Nucleon Scattering

Abstract

An improved version of the one-boson-exchange model is presented. In addition to $\ensuremath{\pi}$, $\ensuremath{\rho}$, $\ensuremath{\omega}$, and ${X}^{0}$, the scalar mesons $\ensuremath{\epsilon}$ and $\ensuremath{\delta}$ are used with their physical masses. The broad width of the $\ensuremath{\rho}$ and $\ensuremath{\epsilon}$ mesons is taken into account. The relativistic Blankenbecler-Sugar equation is utilized over the laboratory scattering energy range 0 to 425 MeV. A better fit to the experimental $N\ensuremath{-}N$ data is obtained than in previous one-boson-exchange models. Reasonable values of the coupling constants are obtained, which agree qualitatively with other experiments. The fitting procedure was done including and excluding $S$ waves in order to test the influence of the core region. An approximate version of the above model is developed using the Schr\odinger equation in place of the Blankenbecler-Sugar equation. A good fit to the experimental scattering data and the deuteron parameters is obtained with coupling constants similar to those of the relativistic model.