Measurement of time-dependent $CP$ violation in $B^0\to K_S^0\ddot{I}{€}^0\ddot{I}{€}^0$ decays

Abstract

We report a measurement of time-dependent $CP$ violation in $B^0\to K_S^0\ddot{I}{€}^0\ddot{I}{€}^0$ decays using a data sample of $772\times 10^6$ $B\bar{B}$ pairs collected by the Belle experiment runnin g at the $\hat{I}\yen (4S)$ resonance at the KEKB $e^{+}{e}^{-}$ collider. This decay proceeds mainly via a $b\to sd\bar{d}$ "penguin" amplitude. The results are $\sin 2\ddot{I}{•}_1^{\mathrm{eff}}=0.92_{-0.31}^{+0.27}$ (stat.) $\pm 0.11$ (syst.) and $\mathcal{A}=0.28\pm 0.21$ (stat.) $\pm 0.04$ (syst.), which are the most precise measurements of $CP$ violati on in this decay mode to date. The value for the $CP$-violating parameter $\sin 2\ddot{I}{•}_1^{\mathrm{eff}}$ is consistent with that obtained using decay modes proceeding via a $b\to c\bar{c}s$ "tree" amplitude.

7 pages, 3 figures, submitted to PRD(RC)