Combined search for the Standard Model Higgs boson using up to 4.9 fb^-1 of pp collision data at √s = 7 TeV with the ATLAS detector at the LHC

Abstract

A combined search for the Standard Model Higgs boson with the ATLAS experiment at the LHC using datasets corresponding to integrated luminosities from 1.04 fb^-1 to 4.9 fb^-1 of pp collisions collected at √s = 7 TeV is presented. The Higgs boson mass ranges 112.9–115.5 GeV, 131–238 GeV and 251– 466 GeV are excluded at the 95% confidence level (CL), while the range 124–519 GeV is expected to be excluded in the absence of a signal. An excess of events is observed around m_H ∼ 126 GeV with a local significance of 3.5 standard deviations (σ). The local significances of H → γγ, H → ZZ(^∗) →ℓ+ℓ-ℓ'+ℓ'- and H → WW(^∗) → ℓ+νℓ'-ν¯, the three most sensitive channels in this mass range, are 2.8σ ,2.1σ and 1.4σ , respectively. The global probability for the background to produce such a fluctuation anywhere in the explored Higgs boson mass range 110–600 GeV is estimated to be ∼ 1.4% or, equivalently, 2.2σ.