Study of the decay ${\bar{B}}^0\to {\mathrm{\Lambda }}_c^{+}\bar{p}{\pi }^{+}{\pi }^{-}$ and its intermediate states

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