pp→ppω reaction near threshold

We analyze the total cross section data for pp→ppω ->ppti> near threshold measured recently at SATURNE. Using an effective range approximation for the on-shell pp S-wave final-state interaction, we extract from these data the modulus |Ω|=0.53 fm⁴ of the threshold transition amplitude Ω. We present a calculation of various (tree-level) meson exchange diagrams contributing to Ω. It is essential that ω emission from the anomalous ωρπ vertex interferes destructively with ω emission from the proton lines. The contribution of scalar σ-meson exchange to Ω turns out to be negligibly small. Without introducing off-shell meson-nucleon form factors the experimental value |Ω|=0.53 fm⁴ can be reproduced with an ωN-coupling constant of g_ωN=10.7. The results of the present approach agree qualitatively with the Jülich model. We also perform a combined analysis of the reactions pp→ppπ⁰, pnπ⁺, ppη, ppω, pn→pnη near threshold.