C. M. Spaltro

Search for nucleon-nucleon correlations in the proton spectral function of 208Pb

Abstract Cross sections for the reaction 208Pb(e,e′p) have been measured with the continuous electron beam from the Amsterdam Pulse-Stretcher facility at NIKHEF-K. The spectral function has been extracted for protons with initial momenta of 300 to 500 MeV/c and binding energies up to 26 MeV. The data are compared to calculations with and without inclusion of nucleon-nucleon correlations. Mean-field predictions significantly underestimate the data and the discrepancy increases with binding energy. For transitions to the valence states the discrepancy is removed by introducing long-range correlations. Above the two-nucleon emission threshold long-range and short-range correlations reduce the discrepancy, but are insufficient to fully account for the measured strength.

The 4He(e, e′p) cross section at large missing energy

Abstract The ( e , e ′ p ) reaction on 4 He nuclei was studied in kinematics designed to emphasize effects of nuclear short-range correlations. The measured cross sections display a peak in the kinematical regions where two-nucleon processes are expected to dominate. Theoretical models incorporating short-range correlation effects agree reaconably with the data.

High Missing-Momentum Components in 4He studied with the e,e'p reaction

The nucleon-nucleon (N N) interaction in the nuclear medium is of fundamental importance for the description of nuclear properties. In particular its short-range part is still poorly known. High-momentum components of the nuclear wave function are sensitive to short range correlations (SRC). Measurement of high momenta will therefore yield information on the N N-interaction at short internucleon distances [1]. Because of the availability of realistic calculations of the wave function of few-body systems, a light nucleus is preferred for such a study. Since the effects of short range correlations are expected to be enhanced in dense nuclei we choose for 4He.

Study of Proton-Neutron Correlations with the reaction 3,4He(e, e′d)

A 3,4He(e, e′d) experiment has been performed at NIKHEF. The data have been taken in both (q, ω)-constant kinematics and in parallel-kinematics for transferred momenta q of 410, 500 and 600 MeV/c using 576 MeV and 370 MeV electron beams. Preliminary results for 3He at 576 MeV are reported here. The (q, ω) constant results allow to extract the contribution of the structure function W LT from the cross section. The parallel kinematics results show an interesting q-dependence that cannot be described by a cluster-knockout model.