Achard, P (reprint author), Univ Geneva, CH-1211 Geneva 4, Switzerland.
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, suid 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(-0.10)(+0.11) +/- 0.03. Front all single W data, the WWgamma gauge coupling parameter kappagamma is measured to be 1.116(-0.086)(+0.082) +/- 0.068. (C) 2002 Published by Elsevier Science B.V.