NEW MEASUREMENTS OF CP VIOLATION IN B~0 → (cc)K~(0(*)) DECAYS FROM BABAR

摘要

We present new measurements of CP asymmetries in B~0 → (cc)K~(0(*)) decays recorded by the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC between 1999 and 2004. We determine sin2β from decay-time distributions of 7730 signal events in a data sample of approximately 227 x 10~6 Υ(4S) → BB decays. The measured value of sin2β = 0.722 ± 0.040(stat) ± 0.023(syst) is in agreement with the value expected from the Standard Model. In a separate time-dependent angular analysis of B → J/ψ K~(*0)(K~(*0) → K_s~0 π~0)) decays we measure cos2β to be positive at 86% CL.