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Elastic electron scattering cross sections have been measured for 6Li at 500 MeV and values of q sup 2, the momentum transfer squared, up to 13 f(m sup (-2)). Calculations including nucleon-nucleon correlations predict a diffraction minimum beyond the range of previous measurements for 6Li. The results for 6Li do show a diffraction minimum at q sup 2 = 8 f(m sup (-2)); they are also compared with a phase shift calculation using an empirical charge distribution. (Author)

The spectra of electrons scattered inelastically from 4 He have been measured at incident energies from 150 MeV to 400 MeV for scattering angles from 38° to 90°. Through the use of a liquid 4 He target, a high momentum resolution (≈0.25%) was obtained, and the 20 MeV 0 + state of the α-particle was observed for the first time in electron scattering. The excitation energy and the total width of this state were determined and are in good agreement with the results from other experimental methods. It was found that the total disintegration cross section appears be smaller than 2(σ p +σ n ) by more than an order of magnitude at the lowest q 2 (≈ 0.33 fm −2 ). In earlier work the assumption of a total cross section of 2(σ p +σ n ) was found to be quite accurate for higher q 2 . As a new result, the partial radiative width for the 0 + state is determined to be Γ rad = 1.1±0.3 meV.

Previous measurements of the transition probabilities for low-energy excitations in 12 C, using high-energy electron scattering techniques, required considerable extrapolation of the data to obtain the desired results. The present paper reports the results of new data obtained at lower values of momentum transferred to the nucleus. Transition widths for the three lowest-energy excited states in 12 C are determined using the new data. The results of the experiment allow a much greater confidence in the method employed in this study for determining transition widths.