Selectivity of the 16O(e,e'pp)} Reaction to Discrete Final States

Resolution of discrete final states in the 16O(e,e'pp)14C 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 0+ ground state and first 2+ state of 14C are reached predominantly by the removal of a1S0 pair from 16O in this reaction, whereas other states mostly arise by the removal of a 3P pair. This theoretical prediction has been supported recently by an analysis of the pair momentum distribution of the experimental data. 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 16O 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 3P proton pair is largely due to the two-body Delta current. The 1S0 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 16O(e,e'pp) reaction involving the lowest few states in 14C. In particular the longitudinal structure function f 00 , which might be separated with superparallel kinematics, turns out to be quite sensitive to the NN potential that is adopted in the calculations.