Search for SM Higgs Decaying to Two Photons via ATLAS Detector

This dissertation reports the discovery potential of the Standard Model Higgs boson with the di-photon decay using the ATLAS detector. First, photon calibration techiques is studied and a likelihood method for photon identification and jet rejection is developed. A method to evaluate photon identification and fake photon backgrounds with data was also discussed. The potential of an inclusive SM Higgs decaying to two photons search and Higgs boson searches in association with one or two high $P_T$ jets is evaluated. Finally an extended maximum likelihood fit together with event classifications was performed to estimate the sensitivity of the search. With 30 fb$^{-1}$ data, the expected sensitivity for the channel Higgs decaying to two photons is above 5 sigma for Higgs masses between 120 and 140 GeV.