Light Higgs Discovery Potential with ATLAS, Measurements of Couplings and Impact on Model Discrimination

A light (mass between 114 and ~200 GeV) Standard Model Higgs boson is favored by precise measurements of electroweak radiative corrections. A light Higgs boson is also expected in Supersymmetric models. This talk reviews the ATLAS discovery potential of a light Higgs boson, with emphasis on the vector boson fusion production modes, which allows a better background rejection. Once discovered, Higgs boson couplings to heavy quarks, taus and vector bosons can be studied by measuring the rate of events in various production and decay channels. The accuracy of these studies is described and the impact on the discrimination between Standard Model and Supersymmetric models is shown.