Production of Single W Bosons at LEP and Measurement of WWgamma Gauge   Coupling Parameters
  Single W boson production in electron-positron collisions is studied with the L3 detector at centre-of-mass energies between 192 GeV and 209 GeV. Events with two acoplanar hadronic jets or a single energetic lepton are selected, and the single W cross section is measured. Combining the results with measurements at lower centre-of-mass energies, the ratio of the measured cross section to the Standard Model expectation is found to be 1.12^{+0.11}_{-0.10}+/-0.03. From all single W data, the WWgamma gauge coupling parameter kappa_gamma is measured to be 1.116^{+0.082}_{-0.086}+/-0.068. 
L3 Collaboration