Study of Triple-Gauge-Boson Couplings ZZZ, ZZ and Z at LEP

Neutral triple-gauge-boson couplings ZZZ, ZZγ and Zγγ have been stud- ied with the DELPHI detector using data at energies between 183 and 208 GeV. Limits are derived on these couplings from an analysis of the re- actions e+e−→ Zγ, using data from the final states γf ¯ f, with f = q or ν, from e+e−→ ZZ, using data from the four-fermion final states qqqq, qq� +� −, qqe+e−, qqν¯ ν, � +� −ν¯ ν and e+e−ν¯ ν, and from e+e−→ Zγ∗, in which the final state γ is off mass-shell, using data from the four-fermion final states q¯ qe+e− and q¯ q� +� −. No evidence for the presence of such couplings is observed, in agreement with the predictions of the Standard Model.