Three-body effects in the nucleon-nucleon interaction on account of particle exchange

Within the scope of a model two aspects of three-body effects in nucleon-nucleon interaction resulting from retardation of the one-pion exchange are dealt with. One of them is treated by deriving energy-dependent mass corrections for the bound Δ-isobar within the model. By the resulting mass shifting the excitation energy of a bound nucleon to a Δ-isobar is increased in average by 10% compared to that of a free nucleon. This leads to a decrease of the share of Δ-components in the three-nucleon state and of the correction of nuclear properties associated therewith by about 10% compared to calculations using as mass of the Δ-isobar the resonance energy in the pion-nucleon scattering. On the other hand the pion-deuteron scattering is also described by the model. The treatment of coulomb interaction making considerable difficulties in a three-particle system, it is neglected. In this paper a way is shown to account for a repulsive coulomb potential between two of the particles in a three-body system. The theory includes the coulomb interaction into the free resolvent. The gap existing until now between this theory and its applicability is closed because the given partial-wave projected coulomb wave functions in the momentum space allow arbitrary operators from the momentum space to be transformed into the coulomb wave representation. (orig.)