Pion absorption in the resonance region

Pion absorption in the resonance region is studied microscopically in terms of the elementary coupling of mesons to nucleons and isobars. Particular emphasis is put on calculating the contribution from genuine two-body absorption and three-body absorption. At low energies the two-body absorption is the most important channel, but around resonance and beyond the three-body absorption becomes important and can account for about 50% of the total absorption cross section. Genuine multiparticle absorption by more than three particles is estimated to be a small fraction of the total. Comparison with the experimental data is made and good agreement with experiment is found for different nuclei and different energies. (orig.)