Observation of a new particle in the search for the Standard Model Higgs boson with the ATLAS detector at the LHC

Abstract

A search for the Standard Model Higgs boson in proton-proton collisions with the ATLAS detector at the LHC is presented. The datasets used correspond to integrated luminosities of approximately 4.8 fb -1 collected at s=7 TeV in 2011 and 5.8 fb -1 at s=8 TeV in 2012. Individual searches in the channels H→ZZ (*) →4ℓ, H→γγ and H→WW (*) →eνμν in the 8 TeV data are combined with previously published results of searches for H→ZZ (*) , WW (*) , bb- and τ + τ - in the 7 TeV data and results from improved analyses of the H→ZZ (*) →4ℓ and H→γγ channels in the 7 TeV data. Clear evidence for the production of a neutral boson with a measured mass of 126.0±0.4(stat)±0.4(sys)GeV is presented. This observation, which has a significance of 5.9 standard deviations, corresponding to a background fluctuation probability of 1.7×10 -9 , is compatible with the production and decay of the Standard Model Higgs boson. © 2012 CERN.