Resonant behaviour in double charge exchange reaction of πmesons on the nuclear photoemulsion

Abstract.The invariant-mass spectra of the ppπ- and pp systems produced in the double charge exchange (DCX) of positively charged pions on photoemulsion are analysed. A pronounced peak is observed in the ppπ- invariant-mass spectrum, while the Mpp spectrum exhibits a strong Migdal-Watson effect of the proton-proton final-state interaction. These findings are in favor of the NN-decoupled NNπ pseudoscalar resonance with T = 0 called d'.