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

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 → Z Z(∗) →4l , H →γγ and H →WW(∗) →eνμν in the 8 TeV data are combined with previously published results of searches for H → Z Z(∗), WW(∗), b¯b and τ+τ− in the 7 TeV data and results from improved analyses of the H → Z Z(∗) →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.