η′ meson production in nucleon-nucleon collisions near the threshold

The production of η′ mesons in the reactions pp → ppη′ and pn → pnη′ at threshold-near energies is analyzed within a covariant effective meson-nucleon theory. The description of cross-section and angular distributions of the available data in this kinematical region in the pp channel is accomplished by including meson currents and nucleon currents with the resonances S11(1650), P11(1710) and P13(1720). Predictions for the pn channel are given. The di-electron production from subsequent η′ Dalitz decay η′ → γγ* → γe+e− is also calculated and numerical results are presented for intermediate energy and kinematics of possible experiments with HADES, CLAS and KEK-PS.