Searching for new physics in events with three leptons with ATLAS

We investigate the potential of the ATLAS detector to discover new physics events containing three leptons ($e$ and $\mu$) and missing transverse momentum in a hadronically quiet environment. Such final states are predicted in a variety of extensions of the Standard Model. In the context of supersymmetric models, they could result from the direct production of gaugino pairs or from gauginos in decay chains. The gauginos may decay leptonically through real or virtual \Wpm{}, \Zo{} or sleptons.