Proton-Proton Triple Scattering at 1.9 GeV

We have measured the Wolfenstein triple-scattering parameters R, D, and A^' at 1.9 GeV for p-p scattering at 90^∘{} in the c.m. system. We find that R=0.11±0.16, A^'=-0.54±0.16, and D=0.91±0.21, where these parameters are defined in the c.m. system. The possibility of a vector character for the strong inter-actions is discussed. We conclude that neither a single vector-meson exchange nor a single pseudoscalar-meson exchange can account for the data. Spin effects are found to remain an important part of the nucleon-nucleon interaction at four-momentum transfer -t=1.8 (GeV/c)².