Neutron spectra at 0° from proton-proton collisions between 647 and 805 MeV

Momentum spectra of neutrons at 0^∘{} from the process pp→npπ⁺ have been measured at 647, 771, and 805 MeV. Absolute cross sections d²σdΩdp and dσdΩ* are given for all three energies. A phenomenological calculation using only S- and P-wave πN phase shifts and an $NN$ final-state interaction appears to account for the shapes and magnitudes of the spectra quite well. Comparison with the process np→pX indicates a non-negligible contribution from nonresonant amplitudes.