A study of $\mathrm{B_s^0}$ meson oscillation using hadronic $\mathrm Z^0$ decays containing leptons

Abstract

A sample of \({\rm Z}^0\) decays containing b-flavoured hadrons is tagged using leptons, and events having precise proper time measurements are selected. These events are used to study \({\rm B}^0_{\rm s}\) oscillations. The flavour (b or \(\rm \bar{b}\)) at decay is determined from the lepton charge while the flavour at production is determined from jet charge or the charge of a second lepton, where available. The experiment was not able to resolve the oscillatory behaviour, and we deduce that the \({\rm B}^0_{\rm s}\) oscillation frequency \(\Delta m_{\rm s} > 5.2\) ps\(^{-1}\) at the 95% confidence level.