Relativistic Description of Nucleon-Nucleon Interaction Using a Complex Potential

Using a three-dimensional reduction of the Bethe-Salpeter equation, we calculate the nucleon-nucleon phase parameters in the energy range of 0-1 GeV of incident laboratory energy. In the elastic energy region the generalized one-boson-exchange potential is assumed for driving terms and in the inelastic energy region an imaginary potential is added. Ingredients of the one-boson-exchange potential are $\pi$, $\rho$, $\omega$, $\eta$, $\delta$, and $S^{*}$ mesons. The dipole form factor is adopted for all the interactions of mesons with nucleons. The broad mass distribution is also taken into account for the $\rho$ and $S^{*}$ resonances. Our imaginary potential which is given by a superposition of regularized Yukawa potentials which have an attractive long-range part and a repulsive core, can describe the peripheral nature of the absorption found in phase-shift analyses. Comparisons of our theoretical phase shifts with those derived by the phase-shift analyses, and of our theoretical observables with experiments at 660 and 970 MeV are made in detail and physical implications are discussed.