Transverse electrodisintegration of the deuteron in the threshold region at high Q2.

Cross sections for 180{degree} deuteron electrodisintegration have been measured near threshold for the {ital Q}{sup 2} range 1.21 to 2.77 (GeV/{ital c}){sup 2}. The data are compared to several nonrelativistic meson-nucleon and hybrid quark-hadron models. The data are in strong disagreement with the impulse approximation, indicating the importance of non-nucleonic degrees of freedom. None of the models are in good agreement with the data at all values of {ital Q}{sup 2}. The ratio {ital W}{sub 1}/{ital W}{sub 2} of inelastic structure functions has been extracted using previous forward angle data and is found to decrease strongly near threshold, also indicating the importance of interaction effects.