Measurement of the branching fraction and charge asymmetry of the decay B+ -> D+ D0bar and search for B0 -> D0 D0bar

We report an improved measurement of the B+ -> D+ D0bar and B0 -> D0 D0bar decays based on 657 10^6 BBar events collected with the Belle detector at KEKB. We measure the branching fraction and charge asymmetry for the B+ -> D+ D0bar decay: B(B+ -> D+ D0bar)=(3.85 ± 0.31 ± 0.38) 10^{-4} and Acp(B+ -> D+ D0bar)=0.00 ± 0.08 ± 0.02, where the first error is statistical and the second is systematic. We also set the upper limit for the B0 -> D0 D0bar decay: B(B0 -> D0 D0bar)< 0.43 10^{-4}at 90% CL.