Search for the Standard Model Higgs Boson in the Diphoton Decay Channel with 4.9 fb⁻¹ of pp Collision Data at √s = 7  TeV with ATLAS

A search for the standard model Higgs boson is performed in the diphoton decay channel. The data used correspond to an integrated luminosity of 4.9 fb⁻¹ collected with the ATLAS detector at the Large Hadron Collider in proton-proton collisions at a center-of-mass energy of √s̅ = 7 TeV. In the diphoton mass range 110-150 GeV, the largest excess with respect to the background-only hypothesis is observed at 126.5 GeV, with a local significance of 2.8 standard deviations. Taking the look-elsewhere effect into account in the range 110-150 GeV, this significance becomes 1.5 standard deviations. The standard model Higgs boson is excluded at 95% confidence level in the mass ranges of 113-115 GeV and 134.5-136 GeV.