Observation of ${B}^{+}\ensuremath{\rightarrow}\ensuremath{\Lambda}\overline{\ensuremath{\Lambda}}{K}^{+}$

Observation of $B^{+} \to Λ \bar{Λ} K^{+}$

Y.-J. Lee et al. (Belle Collaboration)

Phys. Rev. Lett. 93, 211801 – Published 19 November 2004

Abstract

We report the first observation of the charmless hyperonic $B$ decay, $B^{+} \to Λ \bar{Λ} K^{+}$ , using a $140 {f b}^{- 1}$ data sample recorded at the $Υ (4 S)$ resonance with the Belle detector at the KEKB $e^{+} e^{-}$ collider. The measured branching fraction is $B (B^{+} \to Λ \bar{Λ} K^{+}) = ({2.91}_{- 0.70}^{+ 0.90} \pm 0.38) \times 10^{- 6}$ . We also perform a search for the related decay mode $B^{+} \to Λ \bar{Λ} π^{+}$ , but do not find a significant signal. We set a 90% confidence-level upper limit of $B (B^{+} \to Λ \bar{Λ} π^{+}) < 2.8 \times 10^{- 6}$ .