Study of $B\to D^{(*)}(n\pi)$ Hadronic Decays

Based on the dataset of an integrated luminosity of $59.0 ~fb^{-1}$ taken with BaBar detector at $\Upsilon (4S)$ resonance, we study $B \to D^{(*)}\pi$, $B \to D^{(*)}\pi^{0}\pi$ and $B \to D^{(*)}\pi\pi\pi$ decays. These analyses are useful in $CP$ violation studies, test of the factorization hypothesis and Heavy Quark Effective Theory.