Measurement of the Branching Fractions for the Decays B0->D^{*-} ppbar pi^+, B0->D^-ppbar pi^+, B0->D^{*0} ppbar and B0->D^0 ppbar

Abstract

The $B^0$ meson decay modes $B^0 \to D^{*-} p {\bar p} \pi^+$, $D^{-} p {\bar p} \pi^+$, ${\bar D}^{*0} p {\bar p}$, and ${\bar D}^{0} p {\bar p}$ are studied in a sample of $124\times 10^{6}$ $B{\bar B}$ pairs collected with the $BaBar$ detector at the PEP-II collider. The decay of $B^0 \to D^{-} p {\bar p} \pi^+$ is observed for the first time, with a measured branching fraction ${\cal B}(B^0 \to D^{-} p {\bar p} \pi^+)=(3.80\pm 0.35\pm 0.46)\times 10^{-4}$. The following branching fractions are also determined: ${\cal B}(B^0 \to D^{*-} p {\bar p} \pi^+)= (5.61\pm 0.59\pm 0.73)\times 10^{-4}$, ${\cal B}(B^0 \to {\bar D}^{*0} p {\bar p})= (0.67\pm 0.21\pm 0.09)\times 10^{-4}$, and ${\cal B}(B^0 \to {\bar D}^{0} p {\bar p})= (1.24\pm 0.14\pm 0.12)\times 10^{-4}$. In each decay mode the invariant mass spectra of the charmed mesons and the baryons are compared with a pure phase-space hypothesis in order to gain insight into the $B$ meson decay dynamics. In particular, the Dalitz plots of ${\bar D}^{*0} p$ versus ${\bar D}^{*0} {\bar p}$ for $B^0 \to {\bar D}^{*0} p {\bar p}$ and of ${\bar D}^{0} p$ versus ${\bar D}^{0} {\bar p}$ for $B^0 \to {\bar D}^{0} p {\bar p}$ are presented. All results are preliminary.