Study Of The Mechanism Of The Reaction He-4(E,E'p) H-3

A serious breakdown of the distorted-wave impulse approximation has recently been observed in the proton-knockout reaction He-4(e,e''p)H-3. In the phenomenological description of the data, charge-exchange contributions were included through a coupled-channel calculation. New data obtained in a wide range of kinematical configurations are presented in order to study the anomaly in more detail. Its magnitude and dependence on momentum transfer are well accounted for by a newly presented microscopic description of various interaction effects, including meson-exchange currents and charge-exchange processes.