Measurement of Trilinear Gauge Boson Couplings WWV, (V = Z,gamma) in e+e- Collisions at 189 GeV

TL;DR

This paper reports measurements of WWV gauge boson couplings at 189 GeV using DELPHI data, confirming consistency with the Standard Model and extracting W boson moments from various final states.

Contribution

It provides the first combined measurement of WWV couplings at 189 GeV, including the W magnetic dipole and electric quadrupole moments, using multiple final states.

Findings

Results are consistent with Standard Model predictions.

Measured couplings constrain new physics beyond the Standard Model.

W boson moments are extracted with improved precision.

Abstract

Measurements of the trilinear gauge boson couplings WWgamma and WWZ are presented using the data taken by DELPHI in 1998 at a centre-of-mass energy of 189 GeV and combined with DELPHI data at 183 GeV. Values are determined for Delta(g_1^Z) and Delta(kappa_gamma), the differences of the WWZ charge coupling and of the WWgamma dipole coupling from their Standard Model values, and for lambda_gamma, the WWgamma quadrupole coupling. A measurement of the magnetic dipole and electric quadrupole moment of the W is extracted from the results for Delta(kappa_gamma) and lambda_gamma. The study uses data from the final states jjlv, jjjj, lX, jjX and gammaX, where j represents a quark jet, l an identified lepton and X missing four-momentum. The observations are consistent with the predictions of the Standard Model.