We have studied the production of ${\mathit{D}}_{\mathit{s}}$ mesons in the decays of B mesons at the Υ(4S) resonance. We report on the first observation of exclusive B-meson decays B->${\mathit{D}}_{\mathit{s}}^{\mathrm{-}}$${\mathit{D}}^{\mathrm{*}+}$, B→${\mathit{D}}_{\mathit{s}}^{\mathrm{-}}$${\mathit{D}}^{+}$, and B→${\mathit{D}}_{\mathit{s}}^{\mathrm{-}}$${\mathit{D}}^0$. We also present a new measurement of the branching ratio and the momentum spectrum for the inclusive decay B→${\mathit{D}}_{\mathit{s}}$X.

• Received 15 January 1990

DOI:https://doi.org/10.1103/PhysRevLett.64.2117