Measurement of branching fraction and direct $CP$ asymmetry in charmless $B^{+}\to K^{+}{K}^{-}\ddot{I}{€}^{+}$ decays at Belle

Abstract

We report a study of the charmless hadronic decay of the charged $B$ meson to the three-body final state $K^{+}{K}^{-}\ddot{I}{€}^{+}$. The results are based on a data sample that contains $772\times 10^6$ $B\bar{B}$ pairs collected at the $\hat{I}\yen (4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^{+}{e}^{-}$ collider. The measured inclusive branching fraction and the direct $CP$ asymmetry are $(5.38\pm 0.40\pm 0.35)\times 10^{-6}$ and $-0.170\pm 0.073\pm 0.017$, respectively, where the first uncertainties are statistical and the second are systematic. The $K^{+}{K}^{-}$ invariant mass distribution of the signal candidates shows an excess in the region below $1.5$ GeV/$c^2$, which is consistent with the previous studies from BaBar and LHCb. In addition, strong evidence of a large direct $CP$ asymmetry is found in the $K^{+}{K}^{-}$ low-invariant-mass region.

7 pages, 3 figures