A Study of W+W-gamma Events at LEP

TL;DR

This paper analyzes W+W- events with photon radiation at LEP, measuring cross sections, confirming Standard Model predictions, and setting limits on anomalous gauge couplings.

Contribution

It provides the first detailed measurement of W+W- gamma events at LEP and constrains anomalous gauge couplings beyond the Standard Model.

Findings

Measured W+W- gamma cross sections at various energies.

Results align with Standard Model predictions.

Set 95% C.L. upper limits on anomalous vertices.

Abstract

A study of W+W- events accomanied by hard photon radiation produced in e+e- collisions at LEP is presented. Events consistent with being two on-shell W bosons and an isolated photon are selected from 681 pb^-1 of data recorded at 180 GeV < sqrt(s) < 209 GeV. For these data, 187 W+W- candidates are selected with photon energies greater than 2.5 GeV. The selected events are used to determine the W+ W- gamma cross section at five values of sqrt(s). The results are consistent with the Standard Model expectation. These data provide constraints on the related O(alpha) systematic uncertainties on the measurement of the W boson mass at LEP. Finally, the data are used to derive 95% C.L. upper limits on possible anomalous contributions to the W+ W- gamma gamma and W+ W- Z0 gamma vertices.