Limits on anomalous trilinear gauge couplings in Zγ events from pp¯ collisions at √s=1.96 TeV

Seven pages, one figure. To be submitted to Phys. Rev. Lett; Using Zgamma candidate events collected by the CDF detector at the Tevatron Collider, we search for potential anomalous (non-standard-model) couplings between the Z boson and the photon. At the hard scatter energies typical of the Tevatron, standard model Zgamma couplings are too weak to be detected by current experiments; hence any evidence of couplings indicates new physics. Measurements are performed using data corresponding to an integrated luminosity of 4.9 /fb in the Z -> nunubar decay channel and 5.1 /fb in the Z -> l^+l^- (l=mu, e) decay channels. The combination of these measurements provides the most stringent limits to date on Zgamma trilinear gauge couplings. Using an energy scale of Lambda = 1.5 TeV to allow for a direct comparison with previous measurements, we find limits on the CP-conserving parameters that describe Zgamma couplings to be |h_3^{\gamma,Z}| < 0.017 and |h_4^{\gamma,Z}| < 0.0006. These results are consistent with standard model predictions.