180 Degree Electron Scattering from the Deuteron

Transverse electron scattering from the deuteron has been measured at the MIT-Bates Linear Accelerator for eleven incident energies in the range from 133 to 373 MeV, and deuteron excitation energies as large as 222 MeV. These data were acquired at a scattering angle of 180 where the cross sections are directly related to the transverse form factors without the need of Rosenbluth separations. Nuclear interaction effects, such as meson exchange currents and isobar configurations, are predicted to make significant contributions to the magnetic current structure of the deuteron that is sampled in the measurement of the transverse form factor. In this experiment a systematic study was made of predictions for various features of the excitation energy spectrum including the elastic peak, the threshold breakup cusp, the quasielastic peak, the dip region, and the beginning of the deep-inelastic region beyond pion production threshold. Gaseous deuterium and hydrogen targets were utilized for these measurements. The proton elastic cross section was used to set the target thickness normalization. The data were corrected for background due to direct scattering from the beam entrance and exit windows of the gas-target cells. The exact single hard-photon formalism of Mo and Tsai, with a multiplicative correction factor for multiple soft-photon emission, was used in making radiative corrections for the emission of real photons before or after scattering. The experimental data are found to be in qualitative agreement with theory, and support the existence of meson exchange current and isobar configuration effects. For instance the predicted threshold breakup cross section would be significantly lower than the data without the inclusion of meson exchange currents. There are quantitative differences between theory and experiment which indicate the need for further improvement in the theoretical calculations.