Measurement of the Zgamma --> nunu[over ]gamma production cross section and limits on anomalous ZZgamma and Zgammagamma couplings in pp[over] collisions at sqrt[s] = 1.96 TeV

Phys Rev Lett. 2009 May 22;102(20):201802. doi: 10.1103/PhysRevLett.102.201802. Epub 2009 May 22.

Abstract

We present the first observation of the Zgamma --> nunu[over ]gamma process at the Fermilab Tevatron at 5.1 standard deviations significance, based on 3.6 fb;{-1} of integrated luminosity collected with the D0 detector at the Fermilab Tevatron pp[over ] Collider at sqrt[s] = 1.96 TeV. The measured Zgamma production cross section multiplied by the branching fraction of Z --> nunu[over] is 32 +/- 9(stat + syst) +/-2 (lumi) fb for the photon E_{T} > 90 GeV. It is in agreement with the standard model prediction of 39 +/- 4 fb. We set limits on anomalous trilinear Zgammagamma and ZZgamma gauge boson couplings, most of which are the most restrictive to date.