Limits on Anomalous Trilinear Gauge Couplings in Zγ Events from pp Collisions at √s = 1.96 Te V

摘要

Using Zy 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. Zy couplings vanish at tree level and are heavily suppressed at higher orders; hence any evidence of couplings indicates new physics. Measurements are performed using data corresponding to an integrated luminosity of 4.9 fb~(-1) in the Z → vv decay channel and 5.1 fb~(-1) in the Z→ l+l~- (l = μ, e) decay channels. The combination of these measurements provides the most stringent limits to date on Zy trilinear gauge couplings. Using an energy scale of A = 1.5 TeV to allow for a direct comparison with previous measurements, we find limits on the CP-conserving parameters that describe Zy couplings to be h_3~(γ,Z) < 0.022 and h_4~(γ,Z) < 0.0009. These results are consistent with standard model predictions.