Search for the $B\to Y(4260)K,Y(4260)\to J/\ddot{I}ˆ\ddot{I}{€}^{+}\ddot{I}{€}^{-}$ decays

Abstract

We report the results of a search for the $B\to Y(4260)K,Y(4260)\to J/\ddot{I}ˆ\ddot{I}{€}^{+}\ddot{I}{€}^{-}$ decays. This study is based on a data sample corresponding to an integrated luminosity of 711~fb${}^{-1}$, collected at the $\hat{I}\yen (4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^{+}{e}^{-}$ collider. We investigate the $J/\ddot{I}ˆ\ddot{I}{€}^{+}\ddot{I}{€}^{-}$ invariant mass distribution in the range 4.0 to 4.6 GeV/$c^2$ using both $B^{+}\to J/\ddot{I}ˆ\ddot{I}{€}^{+}\ddot{I}{€}^{-}{K}^{+}$ and $B^0\to J/\ddot{I}ˆ\ddot{I}{€}^{+}\ddot{I}{€}^{-}{K}_S^0$ decays. We find excesses of events above the background levels, with a significances of 2.1 and 0.9 standard deviations for charged and neutral $B\to Y(4260)K$ decays, respectively, taking into account the systematic uncertainties. These correspond to upper limits on the product of branching fractions, $\mathcal{B}(B^{+}\to Y(4260)K^{+})\times \mathcal{B}(Y(4260)\to J/\ddot{I}ˆ\ddot{I}{€}^{+}\ddot{I}{€}^{-})<1.4\times 10^{-5}$ and $\mathcal{B}(B^0\to Y(4260)K^0)\times \mathcal{B}(Y(4260)\to J/\ddot{I}ˆ\ddot{I}{€}^{+}\ddot{I}{€}^{-})<1.7\times 10^{-5}$ at the 90\% confidence level.

8 pages, 3 figures, 3 tables