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

TL;DR

This paper reports the first observation of the Zgamma to nunugamma process at the Tevatron, measuring its cross section and setting new limits on anomalous gauge boson couplings, confirming the Standard Model predictions.

Contribution

It provides the first measurement of the Zgamma to nunugamma process and establishes the most restrictive limits on anomalous ZZgamma and Zgammagamma couplings at a hadron collider.

Findings

Observed Zgamma to nunugamma process with 5.1 sigma significance

Measured cross section consistent with Standard Model

Set world's strongest limits on anomalous gauge couplings

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 +- 9 (stat.+syst.) +- 2 (lumi.) fb for the photon ET > 90 GeV. It is in agreement with the standard model prediction of 39 +- 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's strongest.