Update of the Background Studies in the Search for the Higgs Boson in the Two Photons Channel in pp Collisions at √s=7 TeV

This note presents an update of the study of the backgrounds to the search for the Higgs boson decaying into a pair of photons. The analysis is done with 99 pb-1 of pp collision data collected in 2011 with the ATLAS detector at a centre-of-mass energy of 7 TeV. The measured background and its composition are in good agreement with the Standard Model predictions both in terms of overall yield and invariant mass distribution. No excess is observed.