A study of form-factors in $D^0\to K_S \pi^- e^+ \nu_e$ decays

We use 429 fb$^{-1}$ of data recorded by the BaBar detector at the PEP-II electron-positron collider to study the $D^0\to K_S \pi^- e^+ \nu_e$ decay channel. We fit the data to a 5-dimensional distribution of the decay quantities $q^2$, $\cos\theta_V$, $\cos\theta_\ell$, $\chi$ and $m_{K_S\pi}$ and present preliminary measurements of the decay amplitude and the Branching Fraction.