A Measurement of CP Violation in B0 Meson Decays with Belle
  We present a preliminary measurement of the Standard Model CP violation parameter $\sin 2\phi_1$ using the Belle detector. A $6.2~{\rm fb}^{-1}$ sample of events produced by the KEKB asymmetric $e^+e^-$ collider operating at the $\Upsilon(4S)$ resonance is used. We report a preliminary result of $$\sin 2\phi_1=0.45^{+0.43}_{-0.44}({\rm stat})^{+0.07}_{-0.09}({\rm syst}).$$ 
Hiroaki Aihara