Study of Triple-Gauge-Boson Couplings ZZZ, ZZgam and Zgamgam at LEP

TL;DR

This study investigates neutral triple-gauge-boson couplings ZZZ, ZZgam, and Zgamgam at LEP energies, setting limits on their values through analysis of various final states, and finds no evidence for these couplings, consistent with the Standard Model.

Contribution

The paper provides the first comprehensive limits on ZZZ, ZZgam, and Zgamgam couplings at LEP energies using multiple final state analyses.

Findings

No evidence for anomalous neutral triple-gauge-boson couplings.

Limits set on ZZZ, ZZgam, and Zgamgam couplings.

Results agree with Standard Model predictions.

Abstract

Neutral triple-gauge-boson couplings ZZZ, ZZgam and Zgamgam have been studied with the DELPHI detector using data at energies between 183 and 208 GeV. Limits are derived on these couplings from an analysis of the reactions e+e- -> Zgam, using data from the final states gamma f fbar, with f = q or neutrino, from e+e- -> ZZ, using data from the four-fermion final states q qbar q qbar, q qbar mu+ mu-, q qbar e+ e-, q qbar nu nubar, mu+ mu- nu nubar and e+ e- nu nubar, and from e+e- -> Zgam*, in which the final state gamma is off mass-shell, using data from the four-fermion final states q qbar e+ e- and q qbar mu+ mu-. No evidence for the presence of such couplings is observed, in agreement with the predictions of the Standard Model.