Branching fraction, polarization and CP-violating asymmetries in B 0→D*+D*- decays

Abstract We present measurements of the branching fraction, the polarization parameters and CP -violating asymmetries in B 0 → D ∗ + D ∗ − decays using a 140 fb −1 data sample collected at the ϒ ( 4 S ) resonance with the Belle detector at the KEKB energy-asymmetric e + e − collider. We obtain B ( B 0 → D ∗ + D ∗ − ) = [ 0.81 ± 0.08 ( stat ) ± 0.11 ( syst ) ] × 10 −3 , R ⊥ = 0.19 ± 0.08 ( stat ) ± 0.01 ( syst ) , R 0 = 0.57 ± 0.08 ( stat ) ± 0.02 ( syst ) , S = − 0.75 ± 0.56 ( stat ) ± 0.12 ( syst ) and A = − 0.26 ± 0.26 ( stat ) ± 0.06 ( syst ) . Consistency with Standard Model expectations is also discussed.