ISSN - 15507998, Physical Review D - Particles, Fields, Gravitation and Cosmology, 2011, vol. 84, p. -
Measurements of time-dependent CP asymmetries in B→D* π± decays using a partial reconstruction technique
We report results on time-dependent CP asymmetries in B→D *π± decays based on a data sample containing 657×106 BB̄ pairs collected with the Belle detector at the KEKB asymmetric-energy e+e- collider at the Υ(4S) resonance. We use a partial reconstruction technique, wherein signal B→D* π± events are identified using information only from the fast pion from the B decay and the slow pion from the subsequent decay of the D*, where the former (latter) corresponds to D*+(D*-) final states. We obtain CP violation parameters S+=+0.061±0. 018(stat)±0.012(syst) and S-=+0.031±0.019(stat) ±0.015(syst). © 2011 American Physical Society.