Near-threshold η meson production in proton-proton collisions

The production of η mesons has been measured in the proton-proton interaction close to the reaction threshold using the COSY-11 internal facility at the cooler synchrotron COSY. Total cross sections were determined for eight different excess energies (ε) in the range from ε = 0.5 MeV to ε = 5.4 MeV. The energy dependence of the total cross section is well described by the available phase-space volume weighted by FSI factors for the proton-proton and proton-η pairs. (C) 2000 Elsevier Science B.V.