First observation of the decay B-0 -> D*D+*(-)

Abstract

We have observed four fully reconstructed B-0 --> D*+D*- candidates in 5.8 x 10(6) Y(4S) --> B (B) over bar decays recorded with the CLEO detector. The background is estimated to be 0.31 +/- 0.10 events. The probability that the background could produce four or more signal candidates with the observed distribution among D*+ and D*- decay modes is 1.1 x 10(-4). The measured decay rate, B(B-0 --> D*+D*-) = [6.2(-2.9)(+4.0)(stat) +/- 1.0(syst)] x 10(-4), is large enough for this decay mode to be of interest for the measurement of a time-dependent CP asymmetry. [S0031-9007(99)08881-X].