Measurement of the Branching Fraction and CP Content for the Decay B0 --> D*+ D*-

Abstract

We report a measurement of the branching fraction of the decay B^0 --> D^{*+} D^{*-} and of the CP-odd component of its final state using the BaBar detector. With data corresponding to an integrated luminosity of 20.4 fb^{-1} collected at the Upsilon(4S) resonance during 1999-2000, we have reconstructed 38 candidate signal events in the mode B^0 --> D^{*+}D^{*-} with an estimated background of 6.2 \pm 0.5 events. From these events, we determine the branching fraction to be BR(B^0 --> D^{*+}D^{*-}) = (8.3 +/- 1.6(stat) +/- 1.2(syst)) x 10^{-4}. The measured CP-odd fraction of the final state is 0.22 +/- 0.18(stat) +/- 0.03(syst).