Production of Single W Bosons at LEP and Measurement of WWgamma Gauge Coupling Parameters

TL;DR

This paper reports on the measurement of single W boson production and WWgamma gauge coupling parameters at LEP energies, confirming consistency with the Standard Model within experimental uncertainties.

Contribution

First precise measurement of WWgamma gauge coupling parameters using LEP data at energies between 192 and 209 GeV.

Findings

Measured single W cross section aligns with Standard Model predictions.

Determined WWgamma gauge coupling parameter kappa_gamma to be approximately 1.116.

Results support the Standard Model's gauge structure.

Abstract

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.