Measurements of exclusive ${B}_{s}^{0}$ decays at the $\ensuremath{\Upsilon}(5S)$ resonance

Measurements of exclusive $B_{s}^{0}$ decays at the $Υ (5 S)$ resonance

A. Drutskoy et al. (Belle Collaboration)

Phys. Rev. D 76, 012002 – Published 12 July 2007

Abstract

Several exclusive $B_{s}^{0}$ decays are studied using a $1.86 {fb}^{- 1}$ data sample collected at the $Υ (5 S)$ resonance with the Belle detector at the KEKB asymmetric energy $e^{+} e^{-}$ collider. In the $B_{s}^{0} \to D_{s}^{-} π^{+}$ decay mode we find 10 $B_{s}^{0}$ candidates and measure the corresponding branching fraction. Combining the $B_{s}^{0} \to D_{s}^{(*) -} π^{+}$ , $B_{s}^{0} \to D_{s}^{(*) -} ρ^{+}$ , $B_{s}^{0} \to J / ψ ϕ$ , and $B_{s}^{0} \to J / ψ η$ decay modes, a significant $B_{s}^{0}$ signal is observed. The ratio $σ (e^{+} e^{-} \to B_{s}^{*} {\bar{B}}_{s}^{*}) / σ (e^{+} e^{-} \to B_{s}^{(*)} {\bar{B}}_{s}^{(*)}) = (93_{- 9}^{+ 7} \pm 1) %$ is obtained at the $Υ (5 S)$ energy, indicating that $B_{s}^{0}$ meson production proceeds predominantly through the creation of $B_{s}^{*} {\bar{B}}_{s}^{*}$ pairs. The $B_{s}^{0}$ and $B_{s}^{*}$ meson masses are measured to be $M (B_{s}^{0}) = (5370 \pm 1 \pm 3) MeV / c^{2}$ and $M (B_{s}^{*}) = (5418 \pm 1 \pm 3) MeV / c^{2}$ . Upper limits on the $B_{s}^{0} \to γ γ$ , $B_{s}^{0} \to ϕ γ$ , $B_{s}^{0} \to K^{+} K^{-}$ , and $B_{s}^{0} \to D_{s}^{(*) +} D_{s}^{(*) -}$ branching fractions are also reported.