Neutron Exchange in the Reactionp+p→d+π+

Several features of observed $p+p\to d+{\pi }^{+}$ cross sections in the BeV region suggest that a one-particle (in this case, one-neutron) exchange mechanism may play a significant role. We have investigated this possibility. The treatment of the $\mathrm{dnp}$ vertex requires some care; the Fourier transform of the deuteron wave function plays a crucial role in the calculations. The resulting predictions for the angular distribution clearly exhibit the forward peaking which is experimentally observed, although the calculated total cross section, as a function of energy, does not agree very well with experiment.