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