Delta isobar production in the He-4 p -> H-3 pn pi(+) reaction

The He-4 p--> H-3 pn pi(+) reaction channel has been investigated at an inc ident 4He momentum of 8.6 GeV/c in an exclusive approach. It has been shown that the reaction mainly proceeds via pp--> pn pi(+) interaction with (p p i(+)) from Delta(++), while triton is a spectator. The anisotropic angular distribution of the nucleons causes the splitting of ((3)Hn) invariant mass and leads to a natural separation of the interactions occuring either in p roton or 4He vertices. Effects such as the shift of peak position in the (p pi(+)) invariant mass distribution have not been observed. [S0556-2813(98) 07912-6].