A meson--exchange isobar model for the $pi^+$d $leftrightarrow$pp reaction}

We calculated a broad set of observables for the π+d ↔ pp reaction with a relatively simple meson-exchange isobar model. The comparison between the calculated results and experimental data (including spin observables) shows that the model gives an overall phenomenologically acceptable description of the reaction around the Δ resonance. We also take into account the effects due to the inclusion of the Galilei invariant (pseudovector) recoil term in the πNN vertex, of relativistic corrections to the ρ-exchange component of the ΔN transition potential, and of NN final state interaction in the π+d → p + p process. Rescatterings via pion-nucleon interaction in the S–wave have also been included. The model is sufficiently simple to be extended to the case of pion absorption on other light nuclei, in particular 3He (or tritium).