A study of B meson oscillations using hadronic Z0 decays containing leptons

An event sample enriched in semileptonic decays of b hadrons is selected using an inclusive lepton selection from approximately 3.0 million hadronic Z decays collected with the OPAL detector. This sample is used to investigate B meson oscillations by reconstructing a proper decay time for the parent of each lepton, using a jet charge method to estimate the production flavour of this parent, and using the lepton charge to tag the decay flavour. We measure the mass difference between the two Bd mass eigenstates Δmd = 0.444 ± 0.029 +0.020 −0.017 ps−1 . For the Bs system, we find Δms > 3.1 ps −1 at the 95% confidence level. This limit varies only a little if alternative limit setting approaches are adopted. Regions at higher Δms values are also excluded with some methods for setting the limit. By studying the charge symmetry of the Bd mixing structure, we are able to constrain possible CP and CPT violating effects. We measure the CP violation parameter Re B = −0.006 ± 0.010 ± 0.006 and the indirect CPT violating parameter Im δB = −0.020 ± 0.016 ± 0.006 . If we invoke CPT symmetry, then we obtain Re B = 0.002 ± 0.007 ± 0.003 .