Higher Partial Waves in Pp ! Ppp near Threshold

Exclusive measurements of the production of-mesons in the pp ! ppp reaction have been carried out at excess energies of 16 and 37 MeV above threshold. The deviations from phase space are dominated by the proton-proton nal state interaction and this innuences particularly the energy distribution of the meson. However, evidence is also presented at the higher energy for the existence of an anisotropy in the angular distributions of the-meson and also of the nal proton-proton pair, probably to be associated with D-waves in this system interfering with the dominant S-wave term. The sign of the angular anisotropy suggests that-exchange is important for this reaction.