Shell-model approach for three body final states

A scattering theory for reactions with three-particle channels above the two-particle threshold is developed. The S-matrix-technique is used for the calculation of the extended S-matrix. Correlated two-particle wave functions in the exit channels are employed to describe the exact two-particle continuum. For the usual shell model only a few partial waves dominate. The cross section depends on the energy-distribution between the two outgoing nucleons. Numerical results are presented for the model (d, 2n)-reaction exciting 0 + -states in O 16 without Coulomb-effects. The treatment is restricted to three (2p2h)-states with the particles in the (sd)-shell and holes in the p-shell.