A Search for Time-Dependent B0s-B0sbar Oscillations Using Exclusively   Reconstructed Ds+/- Mesons
  A search for Bs0-Bs0bar oscillations is performed using a sample of 400,000 hadronic Z0 decays collected by the SLD experiment. The Bs0 candidates are reconstructed in the Bs0 to Ds-,X channel with Ds- to phi,pi- or K*0K-. The Bs0 production flavor is determined using the large forward-backward asymmetry of polarized Z0 to b,bbar decays and charge information in the hemisphere opposite that of the Bs0 candidate. The decay flavor is tagged by the charge of the Ds+/-. From a sample of 361 candidates with an average Bs0 purity of 40%, we exclude the following values of the oscillation frequency: Delta m_s < 1.4 ps^{-1} and 2.4 < Delta m_s < 5.3 ps^{-1} at the 95% confidence level. 
SLD Collaboration