D(s) production in B-meson decay

Using the CLEO detector at CESR, we have studied the production of $D\sb{s}$ mesons in the decay of B mesons from the $\Upsilon(4S)$ resonance. We report improved measurement of the inclusive rate of B decay to $D\sb{s}$ meson, and present results of the first exclusive reconstruction of the two-body decay $B \to D\sb{s}D$. We have also used a semi-exclusive technique to reconstruct two-body double-charm decays of $\overline B\sp0$ meson which confirms the results derived from the inclusive and exclusive measurements. We have compared our results with existing theoretical calculations.

We have also searched for rare B decays involving $D\sb{s}$ meson. We report here on the upper limit derived from this search.

As a necessary precondition to this analysis, we have searched for and reconstructed several exclusive hadronic decays of $D\sb{S}$ meson including $D\sbsp{s}{+} \to K\sp{\* +} \overline K\sp0$ and $D\sbsp{s}{+} \to \overline K\sp{\* 0}K\sp{\* +}$ which have been observed for the first time. We present here their branching fractions relative to the branching fraction for decay mode $D\sb{S} \to \phi\pi$ which we have measured. These results are compared with various theoretical calculations of weak decay of heavy flavour.