Treatment of nuclear reactions above the two-particle threshold

Abstract

A formalism, exact in principle, is developed for describing nuclear reactions above the two-particle emission threshold. The eigenchannels, i.e. the eigenstates of theS-matrix, are computed directly from the shell model. No artificial assumptions have to be made about the properties of the rescattering of the two final state particles; the final state interactions are completely taken into account. Detailed prescriptions are given on how to reduce the exact description to a form amenable to numerical computations. Finally, long-lived intermediate states leading to the so-called sequential decays can, if so desired, be singled out and treated separately. This again involves no specific assumptions. The treatment is applicable also above the three-or moreparticle threshold.