Studies of Bs - Bs-bar Mixing at SLD

 The SLD Collaboration

We report several studies of the time dependence of Bs - Bs-bar
mixing using a sample of 400,000 hadronic Z0 decays collected
by the SLD experiment at the SLC.
The analyses take advantage of the excellent vertexing efficiency
and resolution of the pixel-based CCD Vertex Detector.
All analyses determine the B or B-bar flavor at production
by exploiting the large forward-backward asymmetry of
polarized Z0 -> b b-bar decays.
This flavor tag is enhanced by incorporating additional information
from the hemisphere opposite that of the reconstructed B decay.
Four separate analyses are presented. Two analyses select semileptonic B
decays. These analyses differ in the technique used to reconstruct the B
decay vertex: inclusive reconstruction using the lepton and all tracks in
the jet, and lepton with a topologically reconstructed D vertex
Two analyses reconstruct inclusive B decays by either
fully reconstructing a Ds decay or by topologically reconstructing
both B and D decay vertices.
The separation between B and B-bar decays is based on the
lepton charge in the first two analyses, and the Ds charge or
the charge difference between B and D vertices in the last two analyses.
The analyses are combined to set a lower limit on the Bs mixing oscillation
frequency with a sensitivity comparable to that of the current world
average.