UC Berkeley

We present new measurements of time-dependent CP asymmetries for B0→D(*)+D(*)- decays using (467±5)×106 BB̄ pairs collected with the BABAR detector located at the PEP-II B Factory at the Stanford Linear Accelerator Center. We determine the CP-odd fraction of the B0→D*+D*- decays to be R =0.158±0.028±0.006 and find CP asymmetry parameters S+=-0.76±0.16±0.04 and C+=+0.00±0.12±0.02 for the CP-even component of this decay and S =-1.80±0.70±0.16 and C =+0.41±0.49±0.08 for the CP-odd component. We measure S=-0.63±0.36±0.05 and C=-0.07±0.23±0.03 for B0→D+D-, S=-0.62±0.21±0. 03 and C=+0.08±0.17±0.04 for B0→D*+D-, and S=-0.73±0.23±0.05 and C=+0.00±0.17±0.03 for B0→D+D*-. For the B0→D*±D decays, we also determine the CP-violating asymmetry A=+0.008±0.048±0.013. In each case, the first uncertainty is statistical and the second is systematic. The measured values for the asymmetries are all consistent with the standard model. © 2009 The American Physical Society.