Study of the He-4(e, e ' d)pn reaction

The cross section for the He-4(e, e'd)pn reaction has been measured in para llel and in (q, omega)-constant kinematics for values of the three-momentum transfer of 406, 495 and 595 MeV/c, and for a range in missing momentum. J ust above threshold this reaction can be characterized as a spin/isospin fl ip transition of the involved pn pair. By using two electron energies (576 and 370 MeV) the longitudinal and transverse structure functions could be s eparated. The cross sections turn out to be purely transverse, as expected for a spin/isospin flip transition. The data are well described by new cova riant and current-conserving calculations that include the major final-stat e interaction effects.