The D(e,e'p) coincidence cross section was measured at angles out of the plane, at an excitation energy of approximately 18 MeV and a momentum transfer of 0.33 fm _1 . This is the first reported measurement of the longitudinal-transverse and transverse-transverse interference terms of the electrodisintegration cross section of the deuteron. The longitudinal plus transverse cross section is also reported. The results are in good agreement with a theoretical calculation carried out with use of the Paris potential.PACS numbers: 25.30.Fj, 25.10,+s, 27.10.+h With the advent of high-duty-cycle electron accelerators, new types of experiments, such as coincidence experiments 1,2 and polarization experiments, 3,4 have become possible. These experiments have the potential to become very powerful tools for probing nuclear structure and the nuclear force.The deuteron, as a two-nucleon system, is of great importance in the investigation of the TV-TV interaction, and thus providing a surer foundation for the study of heavier nuclei. Of special interest in the case of the deuteron is the study of interaction effects such as mesonic-exchange currents (MEC's) and the influence of nuclear isobar configurations (IC's). 5 ' 6 Relativistic effects are also of interest in the reaction. 7 Although the importance of an out-of-plane measurement inThe expression for the cross section includes two interference terms involving the longitudinal-transverse (<) and the transverse-transverse (OTT) cross sections in addition to the longitudinal (a L ) and transverse (a T ) components. These interference terms are not present in inclusive electron-scattering experiments, where no outgoing nucleons are detected. The interference terms are expected to give new information about the TV-TV interaction. The transverse-transverse term, in particular, is sensitive to the existence of MEC's and IC's. According to Eq. (l), an out-of-plane measurement of the coincidence cross section enables the interference terms to be separated from other components.We measured the D(e,e'p) coincidence cross section in reaction planes at 0=45°, 90°, and 135°, and at excitation energies of approximately 18 MeV. A deuterat-coincidence experiments was mentioned some time ago, 6 no experiments have actually been made, because such experiments are difficult to perform with pulsed electron accelerators. The pulse stretcher 8 constructed at Tohoku University made it possible to perform such coincidence experiments. The out-of-plane coincidence experiment for the D(e,e'p) reaction is one of the first such experiments using the high-duty electron beam.In the (e.e'p) coincidence experiment, the direction of the emitted proton momentum p is determined by two angles: 0 P , the polar angle between p and the momentum transfer q, and 0, the azimuthal angle between the scattering plane and the reaction plane. The situation is shown in Fig. 1. The coincidence cross section in the laboratory frame is given by (1) FIG. 1. Geometry of the coincidence D(e,e'p) experiment in the laborato...
