Study of the $\mathit{ZZ}\gamma$ and $\mathit{Z}\gamma \gamma$ Couplings in $\mathit{Z}\left(\nu \nu \right)\gamma$ Production

We have measured the $\mathrm{ZZ}\gamma$ and $Z\gamma \gamma$ couplings by studying $13.1{\mathrm{pb}}^{-1\mathrm{}}$ of $p\overline{p}\to E_t\gamma +X$ data at $\sqrt{s}=1.8\mathrm{}\mathrm{TeV}$ with the DØ detector at the Fermilab Tevatron Collider. This is the first study of hadronic $Z\gamma$ production in the neutrino decay channel. Combining this measurement with our previous results using $Z\to \mathrm{ee}$ and $\mu \mu$ yields the most stringent 95% C.L. limits to date on anomalous couplings: $|h_{30}^Z|<0.4\mathrm{}$, $|h_{40}^Z|<0.06\mathrm{}$ ( $\Lambda =750\mathrm{}\mathrm{GeV}$).