Study of the decay ${\bar{B}}^0\to \hat{I}{›}_c^{+}\bar{p}\ddot{I}{€}^{+}\ddot{I}{€}^{-}$ and its intermediate states

Abstract

We study the decay ${\bar{B}}^0\to \hat{I}{›}_c^{+}\bar{p}\ddot{I}{€}^{+}\ddot{I}{€}^{-}$, reconstructing the Λ_{c}^{+} baryon in the $p{K}^{-}\ddot{I}{€}^{+}$ 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 $\hat{I}{\pounds }_c$ baryons to be $\mathcal{B}[{\bar{B}}^0\to \hat{I}{\pounds }_c(2455{)}^{++}\bar{p}\ddot{I}{€}^{-}]=(21.3\pm 1.0\pm 1.0\pm 5.5)\times 10^{-5}$, $\mathcal{B}[{\bar{B}}^0\to \hat{I}{\pounds }_c(2520{)}^{++}\bar{p}\ddot{I}{€}^{-}]=(11.5\pm 1.0\pm 0.5\pm 3.0)\times 10^{-5}$, $\mathcal{B}[{\bar{B}}^0\to \hat{I}{\pounds }_c(2455{)}^0\bar{p}\ddot{I}{€}^{+}]=(9.1\pm 0.7\pm 0.4\pm 2.4)\times 10^{-5}$, and $\mathcal{B}[{\bar{B}}^0\to \hat{I}{\pounds }_c(2520{)}^0\bar{p}\ddot{I}{€}^{+}]=(2.2\pm 0.7\pm 0.1\pm 0.6)\times 10^{-5}$, where the uncertainties are statistical, systematic, and due to the uncertainty on the $Λ_{c}^{+}\rightarrow\proton\Kmπ^{+}$ branching fraction, respectively. For decays without $\hat{I}{\pounds }_c(2455)$ or $\hat{I}{\pounds }_c(2520)$ resonances, we measure $\mathcal{B}[{\bar{B}}^0\to \hat{I}{›}_c^{+}\bar{p}\ddot{I}{€}^{+}\ddot{I}{€}^{-}{]}_{\mathrm{non}-\hat{\mathrm{I}}{\pounds }_{\mathrm{c}}}=(79\pm 4\pm 4\pm 20)\times 10^{-5}$. The total branching fraction is determined to be $\mathcal{B}[{\bar{B}}^0\to \hat{I}{›}_c^{+}\bar{p}\ddot{I}{€}^{+}\ddot{I}{€}^{-}{]}_{\mathrm{total}}=(123\pm 5\pm 7\pm 32)\times 10^{-5}$. We examine multibody mass combinations in the resonant three-particle $\hat{I}{\pounds }_c\bar{p}\ddot{I}€$ final states and in the four-particle $\hat{I}{›}_c^{+}\bar{p}\ddot{I}{€}^{+}\ddot{I}{€}^{-}$ final state, and observe different characteristics for the $\bar{p}\ddot{I}€$ combination in neutral versus doubly-charged $\hat{I}{\pounds }_c$ decays.

20 pages, 30 figures