Selectivity of the [Formula Presented] reaction to discrete final states

Resolution of discrete final states in the [Formula Presented] reaction may provide an interesting tool to discriminate between contributions from one- and two-body currents in this reaction. This is based on the observation that the [Formula Presented] ground state and first [Formula Presented] state of [Formula Presented] are reached predominantly by the removal of a [Formula Presented] pair from [Formula Presented] in this reaction, whereas other states mostly arise by the removal of a [Formula Presented] pair. This theoretical prediction has been supported recently by an analysis of the pair momentum distribution of the experimental data 1. In this paper we present results of reaction calculations performed in a direct knockout framework where final-state interaction and one- and two-body currents are included. The two-nucleon overlap integrals are obtained from a calculation of the two-proton spectral function of [Formula Presented] and include both long-range and short-range correlations. The kinematics chosen in the calculations is relevant for recent experiments at NIKHEF and Mainz. We find that the knockout of a [Formula Presented] proton pair is largely due to the (two-body) Δ current. The [Formula Presented] pair knockout, on the other hand, is dominated by contributions from the one-body current and therefore sensitive to two-body short-range correlations. This opens up good perspectives for the study of these correlations in the [Formula Presented] reaction involving the lowest few states in [Formula Presented] In particular the longitudinal structure function [Formula Presented] which might be separated with superparallel kinematics, turns out to be quite sensitive to the [Formula Presented] potential that is adopted in the calculations.