Study of $Z\gamma$ events and limits on anomalous $ZZ\gamma$ and $Z\gamma\gamma$ couplings in ppbar collisions at $sqrt(s) = 1.96$ TeV

TL;DR

This paper measures Zγ production in proton-antiproton collisions at 1.96 TeV and sets limits on anomalous couplings, providing constraints that test the Standard Model and search for new physics.

Contribution

First measurement of Zγ production cross section and limits on anomalous ZZγ and Zγγ couplings at Tevatron energies.

Findings

Measured Zγ production cross section with 138-152 candidate events.

Set 95% CL limits on anomalous couplings, e.g., |h_{20,40}^{Z}|<0.020.

Provided constraints for form-factor scales of 750 and 1000 GeV.

Abstract

We present a measurement of the Z\gamma production cross section and limits on anomalous ZZ\gamma and Z\gamma\gamma couplings for form-factor scales of Lambda = 750 and 1000 GeV. The measurement is based on 138 (152) candidate events in the ee\gamma (\mu\mu\gamma) final state using 320 (290) pb^{-1} of ppbar collisions at \sqrt{s} = 1.96 TeV. The 95% C.L. limits on real and imaginary parts of individual anomalous couplings are |h_{10,30}^{Z}|<0.23, |h_{20,40}^{Z}|<0.020, |h_{10,30}^{\gamma}|<0.23, and |h_{20,40}^{\gamma}|<0.019 for Lambda = 1000 GeV.