2023 Impact factor 4.2
Particles and Fields
Eur. Phys. J. C 17, 553-566
DOI 10.1007/s100520000490

Search for trilinear neutral gauge boson couplings
in Z$\gamma$ production at $\sqrt{s}=189$ GeV at LEP

The OPAL Collaboration

G. Abbiendi$^{\rm 2}$ - et al.

2 Dipartimento di Fisica dell' Università di Bologna and INFN, 40126 Bologna, Italy

Received: 31 May 2000 / Published online: 23 October 2000 - © Springer-Verlag 2000

The data recorded at a centre-of-mass energy of 189 GeV by the OPAL detector at LEP are used to search for trilinear couplings of the neutral gauge bosons in the process ${\rm e}^+{\rm e}^-\rightarrow{\rm Z\gamma}$. The cross-sections for multihadronic events with an energetic isolated photon, and for events with a high energy photon accompanied by missing energy are measured. These cross-sections and the photon energy, polar angle and isolation angle distributions are compared to the Standard Model predictions and to the theoretical expectations of a model allowing for ${\rm Z\gamma Z}$ and ${\rm Z\gamma\gamma}$ vertices. Since no significant deviations with respect to the Standard Model expectations are found, constraints are derived on the strength of neutral trilinear gauge couplings.

Copyright Società Italiana di Fisica, Springer-Verlag 2000