Measurements of Branching Fractions of $\ddot{I}„$ Lepton Decays with one or more $K_S^0$

Abstract

We report measurements of branching fractions of $\ddot{I}„$ lepton decays to final states with a $K_S^0$ meson using a 669 fb${}^{-1}$ data sample accumulated with the Belle detector at the KEKB asymmetric-energy $e^{+}{e}^{-}$ collider. The inclusive branching fraction is measured to be $\mathcal{B}(\ddot{I}{„}^{-}\to K_S^0{X}^{-}\hat{I}{½}_{\ddot{I}}„)=(9.15\pm 0.01\pm 0.15)\times 10^{-3}$, where $X^{-}$ can be anything; the exclusive branching fractions are $\mathcal{B}(\ddot{I}{„}^{-}\to \ddot{I}{€}^{-}{K}_S^0\hat{I}{½}_{\ddot{I}}„)=(4.16\pm 0.01\pm 0.08)\times 10^{-3}$, $\mathcal{B}(\ddot{I}{„}^{-}\to K^{-}{K}_S^0\hat{I}{½}_{\ddot{I}}„)=(7.40\pm 0.07\pm 0.27)\times 10^{-4}$, $\mathcal{B}(\ddot{I}{„}^{-}\to \ddot{I}{€}^{-}{K}_S^0\ddot{I}{€}^0\hat{I}{½}_{\ddot{I}}„)=(1.93\pm 0.02\pm 0.07)\times 10^{-3}$, $\mathcal{B}(\ddot{I}{„}^{-}\to K^{-}{K}_S^0\ddot{I}{€}^0\hat{I}{½}_{\ddot{I}}„)=(7.48\pm 0.10\pm 0.37)\times 10^{-4}$, $\mathcal{B}(\ddot{I}{„}^{-}\to \ddot{I}{€}^{-}{K}_S^0{K}_S^0\hat{I}{½}_{\ddot{I}}„)=(2.33\pm 0.03\pm 0.09)\times 10^{-4}$, $\mathcal{B}(\ddot{I}{„}^{-}\to \ddot{I}{€}^{-}{K}_S^0{K}_S^0\ddot{I}{€}^0\hat{I}{½}_{\ddot{I}}„)=(2.00\pm 0.22\pm 0.20)\times 10^{-5}$, where the first uncertainty is statistical and the second is systematic. For each mode, the accuracy is improved over that of pre-$B$-factory measurements by a factor ranging from five to ten. In $\ddot{I}{„}^{-}\to \ddot{I}{€}^{-}{K}_S^0{K}_S^0\ddot{I}{€}^0\hat{I}{½}_{\ddot{I}}„$ decays, clear signals for the intermediate states $\ddot{I}{„}^{-}\to \ddot{I}{€}^{-}{f}_1(1285)\hat{I}{½}_{\ddot{I}}„$ and $\ddot{I}{„}^{-}\to K^{\ast -}{K}_S^0\ddot{I}{€}^0\hat{I}{½}_{\ddot{I}}„$ are observed.

17 pages, 18 figures, submitted to Phys. Rev. D