A Study of Bs Meson Oscillation Using Ds-Lepton Correlations

TL;DR

This study used Ds-lepton correlations from LEP data to investigate Bs meson oscillations, setting a lower limit on the oscillation frequency but not observing the oscillatory behavior directly.

Contribution

First analysis of Bs oscillation using Ds-lepton correlations at LEP, establishing a lower bound on the oscillation frequency with a novel methodology.

Findings

No direct observation of Bs oscillations.

Lower limit on oscillation frequency: Delta m_s > 1.0 ps-1.

Expected sensitivity was 4.1 ps-1.

Abstract

From data collected around the Z resonance by the OPAL detector at LEP, a sample of Bs decays was obtained using Ds^-l^+ combinations, where the Ds^- was fully reconstructed in the phi pi-, K*0K- and Ks0K- decay channels or partially reconstructed in the phi l- nu (X) decay channel. These events were used to study Bs oscillation. The flavor (b or bbar) at decay was determined from the lepton charge while the flavor at production was determined from a combination of techniques. The expected sensitivity of the experiment is 4.1 ps-1. The experiment was not able to resolve the oscillatory behavior, and we deduced that the Bs oscillation frequency Delta m_s > 1.0 ps-1 at the 95% confidence level.