Search for single top quark production at LEP2

Abstract

A search for single top quark production via flavour changing neutral currents (FCNC) was performed with data collected by the OPAL detector at the e^+e^− collider LEP. Approximately 600 pb^(−1) of data collected at –209 GeV were used to search for the FCNC process e^+e^−→tc(u)→bWc(u). This analysis is sensitive to the leptonic and the hadronic decay modes of the W boson. No evidence for a FCNC process is observed. Upper limits at the 95% confidence level on the single top production cross-section as a function of the centre-of-mass energy are derived. Limits on the anomalous coupling parameters κ(γ) and κ(Z) are determined from these results.