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

• Received 4 February 2013

DOI:https://doi.org/10.1103/PhysRevD.87.092004