Angular distributions in J / ψ → p p bar π0 (η) decays

The differential decay rates of the processes J / ψ → p p bar π⁰ and J / ψ → p p bar η close to the p p bar threshold are calculated with the help of the N N bar optical potential. The same calculations are made for the decays of ψ (2 S). We use the potential which has been suggested to fit the cross sections of N N bar scattering together with N N bar and six pion production in e⁺e^- annihilation close to the p p bar threshold. The p p bar invariant mass spectrum is in agreement with the available experimental data. The anisotropy of the angular distributions, which appears due to the tensor forces in the N N bar interaction, is predicted close to the p p bar threshold. This anisotropy is large enough to be investigated experimentally. Such measurements would allow one to check the accuracy of the model of N N bar interaction.