Observation of isovector-isoscalar two-body currents in deuteron knockout from 3He.

The reaction {sup 3}He({ital e},{ital e}{prime}{ital d}){ital p} was measured at four-momentum transfer {ital q}=420 MeV, for proton recoil momentum {ital P}{sub {ital r}}=22, 54, and 62 MeV/{ital c}, in parallel deuteron kinematics. Longitudinal ({ital L}) and transverse ({ital T}) response functions were obtained by means of Rosenbluth separations. The separated response functions are, respectively, found to be dominated by the contributions of isoscalar and isovector two-body currents. The {ital L}/{ital T} ratios are about 3.5. This is an order of magnitude lower than that for elastic scattering on a free deuteron, or what would be expected for a purely isoscalar transition, but approximately agrees with what is theoretically expected for isoscalar plus isovector contributions. {copyright} {ital 1996 The American Physical Society.}