Time Dependent B 0 s − B 0 s Mixing Using Inclusive and Semileptonic B Decays at SLD

We set a preliminary 95% C.L. exclusion on the oscillation frequency of B 0 s − B 0 s mixing using a sample of 400,000 hadronic Z 0 decays collected by the SLD experiment at the SLC between 1996 and 1998. The analyses determine the b-hadron flavor at production by exploiting the large forward-backward asymmetry of polarized Z 0 → bb decays as well as information from the hemisphere opposite that of the reconstructed B decay. In one analysis, B decay vertices are reconstructed inclusively with a topological technique, and separation between B 0 s and B 0 s decays exploits the B 0 s → D − s cascade charge structure. In the other analysis, semileptonic decays are selected and the B decay point is reconstructed by intersecting a lepton track with the trajectory of a topologically reconstructed D meson. The two analyses are combined with a third analysis described elsewhere to exclude the following values of the B 0 s − B 0 s mixing oscillation frequency: ∆m s < 7.6 ps −1 and 11.8 < ∆m s < 14.8 ps −1 at the 95% confidence level.