Measurement of Time-Dependent CP Asymmetries in B0→D(*)±D∓ Decays

We present a first measurement of CP asymmetries in neutral B decays to D+D-, and updated CP asymmetry measurements in decays to D*+D- and D*-D+. We use fully reconstructed decays collected in a data sample of (232±3)×106 Υ(4S)→BB̅ events in the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. We determine the time-dependent asymmetry parameters to be SD*+D-=-0.54±0.35±0.07, CD*+D-=0.09±0.25±0.06, SD*-D+=-0.29±0.33±0.07, CD*-D+=0.17±0.24±0.04, SD+D-=-0.29±0.63±0.06, and CD+D-=0.11±0.35±0.06, where in each case the first error is statistical and the second error is systematic.