Measurement of triple gauge boson couplings from W^+W^- production at sqrt{s} = 172 GeV

TL;DR

This paper reports measurements of triple gauge boson couplings from W-pair production at 172 GeV, using OPAL data, and finds results consistent with the Standard Model, improving understanding of electroweak interactions.

Contribution

First measurement of multiple anomalous triple gauge couplings at 172 GeV, using W-pair production data from LEP2, providing constraints on new physics beyond the Standard Model.

Findings

All measured couplings are consistent with Standard Model predictions.

Improved constraints on anomalous gauge couplings at 172 GeV.

Combined analysis with previous data refines coupling parameter estimates.

Abstract

We present measurements of triple gauge boson coupling parameters using data recorded by the OPAL detector at LEP2 at a centre-of-mass energy of 172 GeV. A total of 120 W-pair candidates has been selected in the q q(bar) q q(bar), q q(bar) l nu(bar)_l, and l nu(bar)_l l(bar)' nu_l' decay channels, for an integrated luminosity of 10.4 pb^-1. We use these data to determine several different anomalous coupling parameters using the measured cross-section and the distributions of kinematic variables. We measure alpha_B-phi = 0.35 + 1.29 - 1.07 +/- 0.38, alpha_W-phi = 0.00 + 0.30 - 0.28 +/- 0.11, alpha_W = 0.18 + 0.49 - 0.47 +/- 0.23, Delta(g_1^z) = -0.03 + 0.40 -0.37 +/- 0.14, Delta(kappa_gamma^(HISZ)) = 0.03 + 0.55 - 0.51 +/- 0.20, and Delta(kappa) = 0.03 + 0.49 - 0.46 +/- 0.21. Combining the alpha_W-phi result with our previous result obtained from the 161 GeV data sample we measure alpha_W-phi = -0.08 + 0.28 - 0.25 +/- 0.10. All of these measurements are consistent with the Standard Model.