anti pp backward scattering and s-channel resonances: upper limit to the anti pp coupling of the S(1929) meson

From the energy dependence of the p̄p and p̄n inelastic cross sections we deduce an upper limit to the resonant contribution in p̄p backward scattering for c.m. energies between 1915 and 1950 MeV. This limit is smaller than the expected contribution from diffraction scattering. The energy dependence of the 180° p̄p elastic cross section in this energy range cannot therefore be directly related to the formation of s-channel resonances.