THE LONGITUDINAL AND TRANSVERSE STRUCTURE FUNCTIONS OF THE HE-4(E, E'P)H-3 REACTION

He-4(e, e'p)H-3 cross sections were measured in parallel kinematics fo r recoil momenta of 30, 90 and 190 MeV/c. For 30 and 90 MeV/c, the cro ss sections were also measured as a function of the momentum transfer between 0.30 and 0.83 GeV/c. A Rosenbluth decomposition of the cross s ections was made, and experimental longitudinal and transverse spectra l functions were derived. The longitudinal spectral function is quench ed by about 40% relative to the transverse. After model-dependent corr ections for final-state interactions, mesonic currents, and charge exc hange scattering, the quenching remains at the level of congruent-to 2 0%. The spectral functions are compared to calculations employing real istic He-4 wave functions. The longitudinal function is below the theo retical value; the transverse function is in agreement. The spectral f unction data reveal no significant q-dependence and imply an r.m.s. pr oton magnetic radius in He-4 within a few percent of the free value.