Measurement of trilinear gauge boson couplings WWV, (V≡Z,γ) in e+e− collisions at 189 GeV

Measurements of the trilinear gauge boson couplings WWγ 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 Δg1Z and Δκγ, the differences of the WWZ charge coupling and of the WWγ dipole coupling from their Standard Model values, and for λγ, the WWγ quadrupole coupling. A measurement of the magnetic dipole and electric quadrupole moment of the W is extracted from the results for Δκγ and λγ. The study uses data from the final states jjℓν, jjjj, ℓX, jjX and γX, 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.