Measurement of the Zgamma to nunugamma cross section and limits on anomalous ZZgamma and Zgammagamma couplings in ppbar collisions at sqrts = 1.96 TeV

Abstract

We present the first observation of the Zgamma to nunugamma process at the 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 ppbar Collider at sqrt{s} = 1.96 TeV. The measured Zgamma cross section multiplied by the branching fraction of Z to nunu is 32 _s16- 9 (stat._s16syst.) _s16- 2 (lumi.) fb for the photon ET > 90 GeV. It is in agreement with the standard model prediction of 39 _s16- 4 fb. We set the most restrictive limits on anomalous trilinear Zgammagamma and ZZgamma gauge boson couplings at a hadron collider to date, with three constraints being the world_s14s strongest.