A correlated model of the nuclear photoeffect

Abstract

A model is constructed for direct photonuclear reactions at intermediate energies, which incorporates the effects of short-range correlations in the initial and final nuclear states. The model is the first consistent one of this type in that i) spurious contributions to the transition amplitude due to nonorthogonality of approximate correlated initial and final nuclear states are eliminated and ii) the model transition amplitude is developed in a well-behaved cluster expansion, with terms arranged in increasing order in a smallness parameter characterizing the correlations. The zeroth-order term gives the conventional shell model description. Explicit expressions for the transition amplitude valid to first order in the effects of the correlations are derived for use in analyses of the (γ,N) and (γ, 2N) data, under the special assumption that the correlations in initial and final states are of the same Jastrow form.