Measurement of Z +γ Production and Search for Anomalous Triple Gauge Couplings in Proton-antiproton Collisions at √S = 1.96 Tev

Abstract

We present a measurement of ppbar->Zγ + X -> e⁺e^-γ + X production using proton-antiproton collision data collected at the Collider Detector at Fermilab at a center of mass energy of 1.96 TeV. Zγ production provides a direct test of the triple neutral gauge couplings. A measurement of Zγ production cross section and search for anomalous ZZγ and Zγγ couplings are presented.

The data presented are from 1.1 fb^-1 of ppbar integrated luminosity collected at the CDF Detector. Electrons from Z decays are selected with E_t > 20 GeV. Photons (E_t > 7 GeV) are required to be well-separated from the electrons. There are 390 eeγ candidate events found with 1.1 fb^-1 of data, compared to the SM prediction of 375.3 à ± 25.2 events. The Standard Model prediction for the cross section for ppbar-> e⁺e^-γ + X production at √s = 1.96 TeV is 4.5 à ± 0.4 pb. The measured cross section is 4.7 à ± 0.6 pb. The cross section and kinematic distributions of the eeγ events are in good agreement with theoretical predictions.

Limits on the ZZγ and Zγγ couplings are extracted using the photon E_t distribution of eeγ events with M_eeγ > 100 GeV/c². These are the first limits measured using CDF Run II data. These limits provide important test of the interaction of the photon and the Z boson.