Search for the Higgs boson in the diphoton final state with 38 pb$^{-1}$ of data recorded by the ATLAS detector in proton-proton collisions at $sqrt{s}$=7 TeV

This note reports on a search for the Standard Model Higgs boson in the diphoton decay channel with the ATLAS detector at a proton-proton center-of-mass energy of $\sqrt{s}$=7 TeV, with an integrated luminosity of 38 pb$^{-1}$. In the 110-140 GeV mass range, the expected upper limit on the cross-section for this search is 19-22 times larger than the Standard Model prediction. The observed exclusions range from 7 times the Standard Model prediction at 127 GeV, to 39 times at 116 GeV. A simulation-based study of signal, incorporating the best current knowledge of the detector performance, is presented and used in the limit setting.