CP violation in B-bar{B} mixing with dilepton events

We report a measurement of the charge asymmetry for same-sign dileptons in $B^0$-$\bar B^0$ mixing. The data were collected with the Belle detector at KEKB. Using a data sample of 78 fb^{-1} recorded at the $\Upsilon(4S)$ resonance and 9 fb^{-1} recorded at an energy 60 MeV below the resonance, we measure $\Asl = (-0.13 \pm 0.60(\text{stat}) \pm 0.56(\text{sys}))%$.