Study of the decay $\bar{B}^{0}\rightarrowΛ_{c}^{+}\bar{p}π^{+}π^{-}$ and its intermediate states

Abstract: We study the decay $$\bar{B}<sup>{0}\rightarrow\Lambda_{c}<sup>{+}\bar{p}\pi<sup>{+}\pi<sup>{-}$$, reconstructing the \Lambda_{c}^{+} baryon in the $p K<sup>{-}\pi<sup>{+}$ mode, using a data sample of $467\times 10<sup>{6}$ $B\bar{B}$ pairs collected with the BaBar detector at the PEP-2 storage rings at SLAC. We measure branching fractions for decays with intermediate $\Sigma_{c}$ baryons to be $${\cal B}[\bar{B}^{{0}\rightarrow\Sigma_{c}(2455)^{{++}\bar{p}\pi^{-}]=(21.3}} \pm 1.0 \pm 1.0 \pm 5.5) \times 10<sup>{-5}$$, $${\cal B}[\bar{B}^{{0}\rightarrow\Sigma_{c}(2520)^{{++}\bar{p}\pi^{{-}]=(11.5\pm}}} 1.0 \pm 0.5 \pm 3.0)\times 10<sup>{-5}$$, $${\cal B}[\bar{B}^{{0}\rightarrow\Sigma_{c}(2455)^{{0}\bar{p}\pi^{+}]=(9.1}} \pm 0.7 \pm 0.4 \pm 2.4)\times10<sup>{-5}$$, and $${\cal B}[\bar{B}^{{0}\rightarrow\Sigma_{c}(2520)^{{0}\bar{p}\pi^{+}]=}} (2.2 \pm 0.7 \pm 0.1\pm 0.6) \times 10<sup>{-5}$$, where the uncertainties are statistical, systematic, and due to the uncertainty on the $\Lambda_{c}<sup>{+}\rightarrow\proton\Km\pi<sup>{+}$ branching fraction, respectively. For decays without $\Sigma_{c}(2455)$ or $\Sigma_{c}(2520)$ resonances, we measure $${\cal B}[\bar{B}^{{0}\rightarrow\Lambda_{c}^{{+}\bar{p}\pi^{{+}\pi^{{-}]<em>{\mathrm{non-\Sigma</em>{c}}}=(79}}}} \pm 4 \pm 4 \pm 20)\times10<sup>{-5}$$. The total branching fraction is determined to be $${\cal B}[\bar{B}^{{0}\rightarrow\Lambda_{c}^{{+}\bar{p}\pi^{{+}\pi^{{-}]_{\mathrm{total}}=(123}}}} \pm 5 \pm 7 \pm 32)\times10<sup>{-5}$$. We examine multibody mass combinations in the resonant three-particle $\Sigma_{c}\bar{p}\pi$ final states and in the four-particle $\Lambda_{c}<sup>{+}\bar{p}\pi<sup>{+}\pi<sup>{-}$ final state, and observe different characteristics for the $\bar{p}\pi$ combination in neutral versus doubly-charged $\Sigma_{c}$ decays.