Quartic gauge couplings from e + e − → W + W − Z

Effective quartic gauge couplings on tree level appear in a strong interacting Higgs scenario, which could be relevant, e.g. if no standard model Higgs would be found 1. This scenario can be described in terms of an effective chiral Lagrangian valid for invariant energies m W,Z < √ s < 4πv, where the vacuum expectation value due to electroweak symmetry breaking is v = (√ 2G F) −1 ≃ 246 GeV. It can be tested in a future linear collider 2. The Higgs potential is given as in the standard model and the Higgs fields can be described by a nonlinear realization of chiral symmetry 3. The spontaneous symmetry breaking leads to masses of the gauge bosons. A systematic one-loop low energy expansion in the energy regime considered here leads to counter terms that require parameters that have to be determined by experiments. Because of the equivalence theorem the Higgs fields can be identified with the longitudinal components of the gauge bosons. Hence these counter terms can be identified with effective (anomalous) couplings between the gauge bosons. The generic quartic terms are