Nucleon-Deuteron Scattering with Δ-Isobar Excitation, II: Elastic Scattering

摘要

The description of neutron--deuteron elastic scattering is based on a coupled-channel two-baryon interaction that allows for virtual excitation of a nucleon to a Δ-isobar. This gives rise to an effective three-nucleon force in three- nucleon systems. The three-particle scattering equations are solved by employing a separable expansion of the two--baryon transition matrix. The Coulomb interaction is not included. Spin-averaged and spin--dependent observables of elastic neutron- deuteron scattering are calculated and compared with experimental data. The calcu- lated results refer to neutron lab energies between 0 and 70 MeV. Some long-standing discrepancies in low-energy spin observables between theoretical predictions and experimental data cannot be removed by the considered a-isobar effects.