Measurement of the $ZZ\gamma$ and $Z\gamma \gamma$ Couplings in $p\bar{p}$ Collisions at $\sqrt{s}=1.8$ TeV

Abstract

We have directly measured the ZZ-gamma and Z-gamma-gamma couplings by studying p pbar --> l+ l- gamma + X, (l = e, mu) events at the CM energy of 1.8$TeVwiththeD0detectorattheFermilabTevatronCollider.Afittothetransverseenergyspectrumofthephotoninthesignalevents,basedonthedatasetcorrespondingtoanintegratedluminosityof13.9p{b}^{-}1($13.3 pb^-1) for the electron (muon) channel, yields the following 95% confidence level limits on the anomalous CP-conserving ZZ-gamma couplings: -1.9 < h^Z_30 < 1.8 (h^Z_40 = 0), and -0.5 < h^Z_40 < 0.5 (h^Z_30 = 0), for a form-factor scale Lambda = 500 GeV. Limits for the Z-gamma-gamma$ couplings and CP-violating couplings are also discussed.

11 pages, 1 table, and 3 figures