Physics at the LHC with the ATLAS detector

The ATLAS experiment at the new CERN proton-proton collider (LHC), with its uniquely high energy in the center of mass of square root s =14 TeV and peak luminosity of 10/sup 34/ cm/sup -1/s/sup -1/, will explore the physics processes at the TeV scale and will look for new particles in a wide range of mass between 100 GeV and 5 TeV. This paper presents an overview of the ATLAS physics potential for a variety of processes: searches for Higgs boson(s) in the standard model and in the MSSM model, searches for supersymmetric particles, quark and lepton compositeness, new gauge bosons and extra- dimensions. (4 refs).