Study of the Decay $B^- \rightarrow D_J^0 \pi^-$

Excited states of the $D$ meson, typically denoted as $D_J$ (or $D^{**}$), provide a unique opportunity to test Heavy Quark Effective Theory (HQET). For one unit of angular momentum ($L = 1$), there are four states of positive parity labeled $D_1$, $D_0^*$, $D_1^{'}$, and $D_2^*$. According to HQET, the $D_1$ decays via a $D$-wave to $D^*\pi$ whereas the $D_2^*$ can decay via $D$-wave to either $D^*\pi$ or $D\pi$. The $D_0^*$ and $D_1^{'}$ should decay via an $S$-wave to $D\pi$ and $D^{*}\pi$ respectively, and are expected to be rather broad. We report here on the Dalitz plot analyses of $B^-$ mesons decaying into $D^{(*)+}\pi^-\pi^-$ final states using 230 million $B^-$ decays collected by the BaBar detector at the PEP-II asymmetric $B$ Factory.