The pp → ppπo reaction at energies close to threshold

Total cross section measurements for the pp → ppπo reaction, at energies near the π production threshold, are analyzed using a coherent formalism, based on a covariant one boson exchange model. By taking into account the nucleon-nucleon and meson-nucleon final state interactions (FSI) coherently, we reproduced the scale and energy dependence of the total cross section. The main contributions to the transition amplitude are due to ρ and ω meson exchanges. The transition amplitudes for the elementary processes pp →q πop and ωp→πop are calculated using vector meson dominance and the usual approximation for πo electroproduction off the proton. The energy dependence is determined almost solely by the ESI correction factor which we identify with the on-shell elastic scattering amplitude for the ppπo→ppπo (3 particles to 3 particles) transition. This amplitude can be calculated from solving the Faddeev equations, or otherwise, it can be estimated using πN and NN elastic scattering data. It is shown that the effects due to isospin I=1/2 and I=3/2 πo-N interactions are significant but, their overall contribution to the ESI factor almost cancels out. This is in marked difference with the results from a similar analysis of the pp→ppη data, where the ηN interaction plays an essential role in reproducing the energy dependence of the total cross sections. Our analysis is basically parameter free as all of the coupling constants and scattering lengths are determined independently from NN and meson-N scattering data. n(authors)