Transverse electrodisintegration of the deuteron in the threshold region at highQ2

Cross sections for 180° deuteron electrodisintegration have been measured near threshold for the ${\mathit{Q}}^2$ range 1.21 to 2.77 (GeV/c${)}^2$. 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 ${\mathit{Q}}^2$. The ratio ${\mathit{W}}_1$/${\mathit{W}}_2$ 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.