Time-dependent CP violation effects in partially reconstructed B0→D∗∓π± decays

We report measurements of time-dependent decay rates for B0→D∗∓π± decays and extraction of CP violation parameters related to ϕ3. We use a partial reconstruction technique, whereby signal events are identified using information only from the primary pion and the charged pion from the decay of the D∗∓. The analysis uses 140 fb−1 of data accumulated at the ϒ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e+e− collider. We measure the CP violation parameters S+=0.035±0.041(stat)±0.018(syst) and S−=0.025±0.041(stat)±0.018(syst).