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 sqrt(s) = 7 TeV in 2011 and 5.8 fb^-1 at sqrt(s) = 8 TeV in 2012. Individual searches in the channels H -> Z Z(*) -> 4l , H -> gamma gamma and H -> W W(*) -> e nu µ nu in the 8 TeV data are combined with previously published results of searches for H -> Z Z(*), WW(*), b¯b and tau+tau- in the 7 TeV data and results from improved analyses of the H -> Z Z(*) -> 4l and H -> gamma gamma 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.