Nuclear-density dependence of the electron-proton coupling

A quasielastic (e,e’p) experiment has been performed on ${}_{}{}^6{}_{}{}^{}\mathrm{Li}$ for both backward- (transverse) and forward-angle (longitudinal) electron kinematics. Cross sections for knockout of protons from two different orbits (1s and 1p) have been measured simultaneously. The densities probed by the (e,e’p) reaction differ by a factor of 4 between these orbits. In both cases the backward/forward cross-section ratio deviates by the same amount from the impulse approximation.