Search for the decays B-0->D(*)D+(*)(-)

Abstract

Using the CLEO-II data set we have searched for the decays B-0 --> D-(*+)D-(*-) We observe one candidate signal event for the decay B-0 --> D*+D*- with an expected background of 0.022 +/- 0.011 events. This yield corresponds to a branching fraction of B(B-0 --> D*+D*-) = [5.3(-3.7)(+7.1)(stat)) +/- 1.0(syst)] X 10(-4) and an upper limit of B(B-0 --> D*-D*-) < 2.2 x 10(-3) at the 90% C.L. We see no significant excess of signal above the expected background level in the other modes,,modes, and we calculate the 90% C.L. upper limits on the branching fractions to be B(B-0 --> D*+/-D-/+ < 1.8 X 10(-3) and B(B-0 --> D+D-) < 1.2 X 10(-3).