A three-body calculation of the πd → πnp reaction in the Δ-resonance region

The reaction d(π^±, pπ^±)n at incident pion momentum 340 MeV/c is analyzed based on a relativistic three-body formalism. The contributions of the various reaction mechanisms such as impulse processes, pion multiple scattering and nucleon-nucleon final-state interactions are investigated for several cases of typical kinematics. The impulse term is dominant when the recoil neutron momentum is small. On the other hand, the NN final-state interaction is found to be relatively important when the recoil neutron momentum is large. The effects of dibaryon resonances which have been suggested in πd elastic scattering are estimated using a phenomenological model. Comparisons with other work are also made.