(Anomalous) Gauge boson couplings

During the LEP2 period the e+e − collider increased its center-of-mass energy from 161 GeV up to 209 GeV. A total integrated luminosity of approximately 700 pb−1 was recorded per experiment. Massive W bosons are dominantly produced in pairs via e +e − interactions and gauge couplings involving the charged gauge bosons W+ and W−, and the neutral gauge bosons γ and Z, are studied by the LEP experiments. The LEP measurement of the coupling of the W boson to the neutral gauge bosons, g Z 1 = 0.984+.022 −.019, κγ = 0.973+.044 −.045, and λγ = −0.028+.020 −.021, are in agreement with the Standard Model expectation g Z 1 = 1, κγ = 1, and λγ = 0. Couplings between tree and four neutral gauge bosons are forbidden by the Standard Model. No evidence has been found for couplings of three neutral gauge bosons, parametrized by f Z,γ 4,5 and h Z,γ 1,2,3,4 . Limits are derived on couplings of four gauge bosons, parametrized by a Z,W 0 /Λ 2 , a W n /Λ 2 and a Z,W c /Λ 2 where Λ represents the energy scale for new physics. A lower limit on the techni-ρ mass of 600 GeV/c2 is set at 95% confidence level by the ALEPH experiment.