Measurement of Time Dependent B(D)0 Anti-B(D)0 Mixing at SLD

The time dependence of B{sub d}{sup o}-{bar B}{sub d}{sup o} mixing has been observed in events containing high P{sub t} leptons using a highly inclusive vertexing method to determine the B decay length and boost. The initial state B hadron flavour is determined using the large forward-backward asymmetry provided by the highly polarized electron beams of SLC in combination with a jet charge technique. From a sample of 150,000 hadronic Z{sup o} decays observed in the SLD detector at the SLC between 1993 and 1995, the mass difference between the two B{sub d}{sup o} mass eigenstates has been measured to be {Delta}m{sub d} = 0.486 {+-} 0.065(stat) {+-} 0.035(syst) ps{sup -1}.