Observation of ZZ production in ppbar collisions at sqrt(s) = 1.96 TeV

TL;DR

This paper reports the first observation of ZZ boson pair production in proton-antiproton collisions at 1.96 TeV, confirming the Standard Model prediction with high statistical significance.

Contribution

It provides the first experimental evidence of ZZ production at the Tevatron, measuring the cross section and establishing the process with over 5 sigma significance.

Findings

Observation of ZZ production with 5.3 sigma significance

Measured cross section of 1.60 pb with uncertainties

Confirmation of Standard Model predictions for ZZ production

Abstract

We present an observation for ZZ -> l+l-l'+l'- (l, l' = e or mu) production in ppbar collisions at a center-of-mass energy of sqrt(s) = 1.96 TeV. Using 1.7 fb-1 of data collected by the D0 experiment at the Fermilab Tevatron Collider, we observe three candidate events with an expected background of 0.14 +0.03 -0.02 events. The significance of this observation is 5.3 standard deviations. The combination of D0 results in this channel, as well as in ZZ -> l+l-nunubar, yields a significance of 5.7 standard deviations and a combined cross section of sigma(ZZ) = 1.60 +/- 0.63 (stat.) +0.16 -0.17 (syst.) pb.