Search for [formula omitted] oscillations at SLD

Abstract

We present preliminary results on the time dependence of B s 0− B s 0 and B d 0− B d 0 mixing using a sample of 400, 000 hadronic Z 0 decay collected by the SLD experiment at the SLC. The analyses take advantage of the excellent decay length resolution of the CCD vertex detector. The B or B production flavor is determined by exploiting the large forward-backward asymmetry of polarized Z 0 → b b decays. This flavor tag is enhanced by incorporating additional information from the hemisphere opposite that of the reconstructed B decay. The B d 0- B d 0 mixing analysis uses the charge of high momentum kaons to identify the B or B decay flavor. The result is Δm d = 0.503 ± 0.028(stat) ± 0.020(syst) ps −1. The results of three separate B s 0- B s 0 mixing analyses are presented. These analyses determine the B decay flavor using the lepton charge in B semileptonic decays, the charge of fully reconstructed D s decays, and the charge difference between topologically reconstructed B and D decays. The three analyses are combined to set a lower limit on the B s 0 − B s 0 oscillation frequency of 12.0 ps −1 at 95% CL.