J. Layssac

Signatures of the anomalous

The possible form of New Physics (NP) interactions affecting the ZZZ, ZZγ and Zγγ vertices, is critically examined. Their signatures and the possibilities to study them, through ZZ and Zγ production, at the e e + Colliders LEP and LC and at the hadronic Colliders Tevatron and LHC, are investigated. Experimental limits obtained or expected on each coupling are collected. A simple theoretical model based on virtual effects due to some heavy fermions is used for acquiring some guidance on the plausible forms of these NP vertices. In such a case specific relations among the various neutral couplings are predicted, which can be experimentally tested and possibly used to constrain the form of the responsible NP structure.

Z_{\gamma}

We examine the Standard and the New Physics (NP) contributions to the ZZZ, ZZγ and Zγγ neutral gauge couplings. At the one-loop level, if we assume that there is no CP violation contained in NP beyond the Standard Model one, we find that only CP conserving neutral gauge couplings are generated, either from the standard quarks and leptons, or from possible New Physics (NP) fermions. Bosonic one-loop diagrams never contribute to these couplings, while the aforementioned fermionic contributions satisfy h Z ≃ −f 5 , h Z = h 4 = 0. We also study examples of two-loop NP effects that could generate non vanishing h ,Z couplings. We compare quantitative estimates from SM, MSSM and some specific examples of NP contributions, and we discuss their observability at future colliders.

and

We establish explicit analytic expressions for the e+e− → W+W− cross sections, asymmetries and W± spin density matrix elements in terms of the complete set of anomalous three-boson couplings. This should be useful for performing a model-independent analysis of LEP 2 or future high energy collider data. Sensitivities to the various three-boson couplings are discussed and possible ways to disentangle their effects are proposed.

Z Z

Abstract. We study the helicity amplitudes of the process

production at the lepton and hadron colliders

\gamma \gamma \to Z Z

New and Standard Physics contributions to anomalous Z and γ self-couplings †

in the Standard Model at high energy. These amplitudes receive contributions from the W and charged quark and lepton loops, analogous to those encountered in the

ANALYTIC EXPRESSIONS OF CROSS SECTIONS, ASYMMETRIES AND W DENSITY MATRICES FOR e+e− → W+W− WITH GENERAL THREE-BOSON COUPLINGS

\gamma \gamma \to \gamma\gamma, \gamma Z

The \(\gamma \gamma \to Z Z \) process and the search for virtual SUSY effects at a \(\gamma \gamma \) Collider

cases studied before. But

Limits on direct new physics effects from 1991 LEP data

\gamma \gamma \to ZZ

Processese−e+→γγ,Zγ,ZZin the standard model and the minimal supersymmetric standard model

also receives contributions from the Higgs s-channel poles involving the effective Higgs-