Evidence for the production of three massive vector bosons with the ATLAS detector

Abstract

The search for the production of three massive vector bosons in proton-proton collisions, performed using data at s = 13 TeV recorded with the ATLAS detector at the Large Hadron Collider in the years 2015-2017, corresponding to an integrated luminosity of 79:8 fb.-1, is presented. Events with two same-sign leptons (electrons or muons) and at least two reconstructed jets are selected to search for WWW vvqq. Events with three leptons without any same-flavour opposite-sign lepton pairs are used to search for WWW vqq, while events with three leptons and at least one same-flavour opposite-sign lepton pair and one or more reconstructed jets are used to search for WWZ vv. Finally, events with four leptons are analysed to search for WWZ vv and WZZ qq. Evidence for the joint production of three massive vector bosons is observed with a significance of 4.1 standard deviations, where the expectation is 3.1 standard deviations.