A double nucleon exchange model for the « ABC » production in the pn → d (ππ)0 reaction

A double nucleon exchange model is proposed for the ABC production in the pn → d(ππ)0 reaction. Important low-mass enhancements are obtained in the invariant ππ mass spectrum similarly to what happens in a Deck model. The same type of mechanism also provides an explanation for the experimentally observed peak at the highest invariant ππ masses.