Role of the low-lying nucleon resonances in the pp¯→ψη reaction

Abstract

Within the effective Lagrangian approach, we study the p p → ψη (ψ ≡ ψ(3686), J/ψ) reaction at the low energy where the contributions from nucleon pole and low-lying nucleon resonances, N(1520), N(1535) and N(1650) are considered. All the model parameters are determined with the help of current experimental data on the decay of ψ → p pη. Within the model parameters, the total and differential cross sections of the p p → ψη reaction are predicted. We show that the relative phases between different amplitudes of different nucleon resonance will change significantly the angular distributions of the pp → ψη reaction. Therefore, we conclude that these reactions are suitable to study experimentally the properties of the low lying nucleon resonance and the reaction mechanisms. We hope that these theoretical calculations could be tested by the future experiments.