Limits on the quartic couplings $Z\gamma\gamma\gamma$ and $ZZ\gamma\gamma$ from $e^+e^-$ colliders

TL;DR

This paper derives experimental limits on quartic neutral gauge boson couplings using LEP 2 data and projects potential improvements at future linear colliders, contributing to the search for physics beyond the Standard Model.

Contribution

First analysis to set experimental bounds on $Z ext{--}\gamma ext{--}\gamma ext{--}\gamma$ and $Z ext{--}\text{Z} ext{--}\gamma ext{--}\gamma$ couplings from LEP data, with projections for future colliders.

Findings

LEP 2 data constrains couplings to $10^{-5}$ and $10^{-3}$ $GeV^{-4}$ and $GeV^{-2}$ respectively.

Future colliders could improve these bounds by one or two orders of magnitude.

Current limits are above Standard Model predictions.

Abstract

We obtain limits on the quartic neutral gauge bosons couplings $Z\gamma\gamma\gamma$ and $ZZ\gamma\gamma$ using LEP 2 data published by the L3 Collaboration on the reactions $e^+e^-\to \gamma\gamma\gamma, Z\gamma\gamma$. We also obtain $95 \%$ C. L. limits on these couplings at the future linear colliders energies. The LEP 2 data induce limits of order $10^{-5}$ $GeV^{-4}$ for the $Z\gamma\gamma\gamma$ couplings and of order $10^{-3}$ $GeV^{-2}$ for the $ZZ\gamma\gamma$ couplings, which are still above the respective Standard Model predictions. Future $e^+e^-$ linear colliders may improve these limits by one or two orders of magnitude.