SM H-->gamma-gamma discovery potential with ATLAS

This presentation reports the discovery potential of Standard Model Higgs boson decaying into two photons. The performance aspects of photon reconstruction, photon conversion, vertex correction, photon identification and jet rejection are discussed. The potential of an inclusive,Higgs in associated with 1, 2 high Ptjets are also evaluated including higher order QCD corrections on signal and background. Studies on the associated production processes are also discussed. Finally the signal sinificance are extracted not only by event counting but also with by using maximum likelihood fit with various event classificattions and discriminating variables.