Measurements of the Branching Fractions $\mathcal{B}(B^{-}\to \bar{\hat{I}}{›}_c^{-}\hat{I}{ž}_c^{{}^{\prime }0})$, $\mathcal{B}(B^{-}\to \bar{\hat{I}}{›}_c^{-}\hat{I}{ž}_c(2645{)}^0)$ and $\mathcal{B}(B^{-}\to \bar{\hat{I}}{›}_c^{-}\hat{I}{ž}_c(2790{)}^0)$

Abstract

Using the data sample of 711 fb${}^{-1}$ of $\hat{I}\yen (4S)$ on-resonance data taken by the Belle detector at the KEKB asymmetric-energy electron-positron collider, we present the first measurements of branching fractions of the decays $B^{-}\to \bar{\hat{I}}{›}_c^{-}\hat{I}{ž}_c^{{}^{\prime }0}$, $B^{-}\to \bar{\hat{I}}{›}_c^{-}\hat{I}{ž}_c(2645{)}^0$, and $B^{-}\to \bar{\hat{I}}{›}_c^{-}\hat{I}{ž}_c(2790{)}^0$. The signal yields for these decays are extracted from the recoil mass spectrum of the system recoiling against $\bar{\hat{I}}{›}_c^{-}$ baryons in selected $B^{-}$ candidates. The branching fraction of $B^{-}\to \bar{\hat{I}}{›}_c^{-}\hat{I}{ž}_c(2790{)}^0$ is measured to be $(1.1\pm 0.4\pm 0.2)\times 10^{-3}$, where the first uncertainty is statistical and the second systematic. The 90\% credibility level upper limits on $\mathcal{B}(B^{-}\to \bar{\hat{I}}{›}_c^{-}\hat{I}{ž}_c^{{}^{\prime }0})$ and $\mathcal{B}(B^{-}\to \bar{\hat{I}}{›}_c^{-}\hat{I}{ž}_c(2645{)}^0)$ are determined to be $6.5\times 10^{-4}$ and $7.9\times 10^{-4}$, respectively.

9 pages, 3 figures