Of Bound and Scattering States of Three – Nucleon Systems

A variational technique to describe the ground and scattering states below the break–up threshold for a three-nucleon system is developed. The method consists in expanding the wave function in terms of correlated Harmonic Hyper-spherical functions suitable to handle the large repulsion contained in the nuclear potential at short distances; three body forces have also been considered. The inclusion of the pp Coulomb repulsion in the p–d processes does not cause any particular problem, since no partial wave decomposition of the interaction is performed. Accurate numerical results are given for ground state properties and scattering lenghts, phase shifts and mixing parameters at three different energies of the incident nu-cleon. The agreement with other available results and with experimental analyses is higlly satisfactory.