LOW-ENERGY EFFECTS OF NEW INTERACTIONS IN THE ELECTROWEAK BOSON SECTOR

Novel strong interactions in the electroweak bosonic sector are expect ed to induce effective interactions between the Higgs doublet field an d the electroweak gauge bosons which lead to anomalous WWZ and WWgamma vertices once the Higgs field acquires a vacuum expectation value. Us ing a linear realization of the Goldstone bosons, we consider a comple te set of dimension-six operators which are SU(2) x U(1) gauge invaria nt and conserve C and P. This approach allows us to study effects of n ew physics which originates above 1 TeV and the Higgs boson mass depen dence of the results can be investigated. Four of the dimension-six op erators affect low energy and present CERN LEP experiments at the tree level. Another five influence neutral and charged current experiments at the one-loop level and three of these lead to anomalous WWZ and WW gamma vertices. Their loop contributions are at most logarithmically d ivergent, and these logarithmic divergences can be understood as renor malizations of the four operators which contribute at the tree level. Constraints on the remaining five operators can be obtained if one ass umes the absence of cancellations between the tree level and one-loop contributions. The resulting bounds on anomalous triple gauge boson co uplings are modest, which emphasizes the importance of direct measurem ents of the triple gauge boson vertices, e.g., in W+W- production at L EP II.