We have extended a model for the $\gamma N\to \pi\pi N$ reaction to virtual photons and selected the diagrams which have a $\Delta$ in the final state. The agreement found with the $\gamma_v p\to\Delta^0\pi^+$ and $\gamma_v p\to\Delta^{ ++}\pi^-$ reactions is good. The sensitivity of the results to $N\Delta$ transition form factors is also studied. The present reaction, selecting a particular final state, is an extra test for models of the $\gamma_{ v} N\to \pi\pi N$ amplitude.
Categories: nucl-th