MECHANISM OF THE REACTION HE-4(E,E'D)H-2

The cross section for the He-4(e,e'd) H-2 reaction has been measured as a function of the four-momentum transfer q at a missing momentum of 125 MeV/c. The data show that this reaction cannot be described as quasielastic knockout of a deuteron. In a microscopic description of the (e,e'd) cross section, assuming a direct knockout mechanism, the q dependence reflects the p-n relative wave function in He-4. However, even a calculation in this framework using a realistic He-4 wave function does not describe the data, indicating that other reaction mechanisms play a non-negligible role.