Positive pion production on 3He by protons at the energy of the Δ(33) resonance and above

The angular distributions of pions produced by 3 He(p, π + ) 4 He at lab. energies of 415 and 716 MeV have been measured up to θc.m. ≈ 100°. Two simple calculations, in the framework of one-nucleon and two-nucleon mechanisms, are presented and some approximations discussed. It is concluded that more elaborate calculations involving real or virtual isobar resonances have to be done.