Time Dependent B0s - B0s-bar Mixing Using Inclusive and Semileptonic B Decays at SLD

Abstract

We set a preliminary 95% C.L. exclusion on the oscillation frequency of B0s - B0s-bar mixing using a sample of 400,000 hadronic Z0 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 Z0 -> b b-bar 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 B0s and B0s-bar decays exploits the B0s -> Ds- 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 B0s - B0s-bar mixing oscillation frequency: Delta m_s < 7.6 ps-1 and 11.8 < Delta m_s < 14.8 ps-1 at the 95% confidence level.