标题： 在LEP2上寻找单顶夸克产生 显示英文标题

标题： Search for Single Top Quark Production at LEP2

摘要： 通过在e+e-对撞机LEP上由OPAL探测器收集的数据，进行了通过味改变中性流（FCNC）产生单个顶夸克的搜索。 大约600 pb-1的数据在sqrt(s) = 189 - 209 GeV下收集，用于搜索FCNC过程e+ e- -> tc(u) -> bWc(u)。 此分析对W玻色子的轻子衰变模式和强子衰变模式都敏感。 未观察到FCNC过程的证据。 根据质心系能量，推导出单个顶夸克产生截面在95%置信度水平上的上限。 从这些结果中确定了异常耦合参数kappa_gamma和kappa_Z的限制。 显示英文摘要

摘要： 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 sqrt(s) = 189 - 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 kappa_gamma and kappa_Z are determined from these results.