Prospects for early dicoveries of high mass resonances with the ATLAS experiment at the LHC

Many extensions of the Standard Model predict the existence of heavy resonances : grand unified theories, technicolor, extra dimensions. The discovery of a heavy resonance would open a new area in our understanding of elementary particles and their interactions. Heavy resonances are expected to appear around the TeV scale. With a center-of-ma ss energy of √ s = 14 TeV, the LHC will be able to search for resonances up to a mass of 5-6 TeV. To achieve the search for new heavy resonances, the ATLAS detector has been specially designed to reconstruct high p T particle