A study of B0s meson oscillation using hadronic Z0 decays containing leptons

TL;DR

This study investigates B_s meson oscillations using hadronic Z0 decays with leptons, but could not resolve the oscillations and set a lower limit on the oscillation frequency at 95% confidence.

Contribution

First analysis of B_s meson oscillations in Z decays using lepton tagging and jet charge methods, establishing a lower bound on oscillation frequency.

Findings

Oscillations not resolved within experimental sensitivity.

Lower limit on Δm_s > 5.2 ps^-1 at 95% confidence.

Method demonstrated effective flavor tagging in Z decays.

Abstract

A sample of Z decays containing b-flavoured hadrons is tagged using leptons, and events having precise proper time measurements are selected. These events are used to study Bs oscillations. using the lepton to tag the decay b-flavour and jet charge or a second lepton, where available, to determine the produced b-flavour. The flavour (b or b-bar) 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 Bs oscillation frequency Delta(ms)> 5.2ps-1 at the 95% confidence level.