We report on the observation of $B^0\to D^{*0}{\pi }^{+}{\pi }^{+}{\pi }^{-}{\pi }^{-}$ decays. The branching ratio is $(0.30\mathrm{}\pm 0.07\pm 0.06)\%.$ Interest in this particular mode was sparked by Ligeti, Luke and Wise who propose it as a way to check the validity of factorization tests in $B^0\to D^{*+}{\pi }^{+}{\pi }^{-}{\pi }^{-}{\pi }^0$ decays.

• Received 23 May 2001

DOI:https://doi.org/10.1103/PhysRevD.65.012002