Single W Boson Production at √s = 189 GeV

Single W boson production is analyzed in a data sample collected by L3 detector at Large Electron Positron Collider in 1998. The integrated luminosity is 176.4pb^-1 with center-of-mass energy at √s = 189GeV. The signal consists of large missing energy final states with a single energetic lepton or two hadronic jets. The total cross section of single W production is measured to be 0.58 ± 0.13 ± 0.04pb, in good agreement with standard nmodel prediction. From this measurement, the limits on the anomalous γWW triplegauge-boson couplings are derived at 95% confidence level: -0.48<Δκ_γ< 0.38 and -0.50 < λ_γ< 0.41 .