A study of deuteron stripping reactions.

A study is made of the extent to which the DWBA theory, in its most refined form, can account for the observed forward angle j dependence, in deuteron stripping reactions, and the inverse pick-up reactions. Calculations have been performed including configuration mixing effects, in the evaluation of the form factor for l = 3 neutron pick-up reactions on Ni58, and including the D state component of the deuteron wavef unction. A three body model for deuteron stripping reactions, which has recently been proposed, is also investigated. This theory, which includes coupling to the broken up triplet S wave states of the neutron-proton system, in an adiabatic approximation, has been extended to include coupling to the singlet S wave states of the neutron-proton system, and applied to a variety of experimentally observed reactions. The adiabatic prescription for stripping reactions is found to lead to a greater l-space localization of the radial integrals which determine the cross section, than the conventional theory. The explanation of the l-space localization produced by the adiabatic theory, leads to an understanding of the mechanism by which various regions of configuration space contribute to the reaction. The adiabatic theory is found to give good agreement with experiment, for energies in the deuteron channel of approximately 20 MeV. The formalism developed for the inclusion of coupling to the singlet channel, is applied to the calculation of cross sections and polarizations, for several of the reactions analysed in earlier sections, using the adiabatic theory without singlet coupling. The effect of this coupling is found to be very small for the observable quantities calculated, and largest for the tensor polarization calculations at back angles. In all cases, the effect of coupling to the singlet channel of the neutron-proton system, was less than the other ambiguities in the theory