Multistep direct emission from nucleon-induced reactions
Abstract.Unbound 1p1h states are excited together with the bound ones in one-step direct processes induced by nucleons of energy greater than the particle binding energy. The cross-sections of the one-step direct reactions to bound final states are folded into a convolution integral to obtain the multistep cross-sections. This is done in the framework of the theory of Feshbach, Kerman and Koonin (FKK) that describes the emission of one particle. The processes to unbound 1p1h final states give rise to more complicated direct reactions, that are evaluated by an approximate method. The comparison of the theory with inclusive proton inelastic scattering by iron and with the charge exchange (p,n) reaction on zirconium is revised, at energies from 25 MeV to 120 MeV. It is shown that in the case of the (p,n) reaction the theory of FKK does not account for approximately 35% of the direct processes.