Unified Reaction Formulation with Two Particles in the Continuum

By means of a Faddeev-like method, a formulation of nuclear reactions leading to three-fragment final channels is presented. It is a shell-model theory of nuclear reactions in which one can, in principle, deal with two particles in the continuum in the intermediate states. The amplitude also includes as one term the distorted-wave $t$-matrix approximation (DWTA). An approximate treatment of the resonance-type term leads to a two-step process for ($p, 2p$) reactions. The importance of such a mechanism, which proceeds via the 1p-1h or 2p-2h states of the target nucleus, is presented for reactions which heretofore have been analyzed by means of the DWTA.