On the nature of isovector exchange in the reaction nucleonnucleon-nucleon nucleonπ by comparison with elastic πnucleon scattering

The results of a cross channel isospin amplitude analysis of the reaction nucleon-nucleon-nucleon-nucleonπ concerning isovector exchange cross-sections for production of nucleonπ systems of isospin 1/2 and 3/2, σsub(1/2)sup(1) and σsub(3/2)sup(1), respectively, have been compared with πnucleon elastic-scattering data. No off-mass-shell corrections are made. The elastic data are normalized to the σsub(3/2)sup(1) cross-section in the Δ(1236) mass region and it is found that in the energy range (7/20)GeV pion exchange gives an important contribution to σsub(1/2)sup(1). The relative contribution seems to decrease with increasing energy