Selectivity of the O(e,epp) reaction to discrete final states

Resolution of discrete final states in the O(e,epp)C reaction may provide an interesting tool to discriminate between contributions from oneand two-body currents in this reaction. This is based on the observation that the 0 ground state and first 2 state of C are reached predominantly by the removal of a S0 pair from O in this reaction, whereas other states mostly arise by the removal of a P 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 knock-out framework where final-state interaction and oneand two-body currents are included. The two-nucleon overlap integrals are obtained from a calculation of the two-proton spectral function of O 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 knock-out of a P proton pair is largely due to the (two-body) ∆-current. The S0 pair knock-out, 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 O(e,epp) reaction involving the lowest few states in C. In particular the longitudinal structure function f00, which might be separated with super-parallel kinematics, turns out to be quite sensitive to the NN potential that is adopted in the calculations.