Pion electroproduction on proton and deuteron

The cross sections for the p(e,e'π+)n and d(e,e'π+)2n reactions are calculated using a simple model with pion, nucleon and Δ-resonance degrees of freedom, for the kinematical conditions used in a recent Saclay experiment. The final-state interactions between the two outgoing neutrons are found to have a large effect on the d(e,e'π+)2n reaction. The calculated quenching of the π+ production cross section for deuterium is in agreement with that observed experimentally. It is predicted that, due to the strong final-state interaction in the singlet S state of the two neutrons, the e,e'π+ cross-section can have a large dependence on the orientation of deuteron spin. In principle this dependence can be observed with tensor polarized deuterium targets under suitable kinematical conditions