Search for the Standard Model Higgs boson in the diphoton decay channel with 4.9 fb-1 of ATLAS data at sqrt(s)=7TeV

This note presents a search for the Standard Model Higgs boson in the diphoton decay channel in proton-proton collisions at a centre-of-mass energy of sqrt(s)=7 TeV using data corresponding to an integrated luminosity of 4.9 fb-1 collected with the ATLAS detector at the LHC. Over the diphoton mass range 110-150 GeV the maximum deviation from the background-only expectation is observed at 126 GeV with a local significance of 2.8 standard deviations. Taking the look-elsewhere effect into account, the significance is 1.5 standard deviations. The expected cross section exclusion at 95% confidence level varies between 1.6 and 2.9 times the Standard Model cross section over the mass range 110-150 GeV. The observed exclusions lie between 0.9 and 4.0 times the Standard Model cross section, and a Standard Model Higgs boson is excluded at 95% confidence level in the mass range of 114-115 GeV and 135-136 GeV.