ATLAS SUSY searches in 2-lepton channels and data-driven method to estimate the diboson standard model background

The search for physics beyond the standard model (BSM) is one of the most important goals of the general purpose detector ATLAS at the Large Hadron Collider at CERN. An example of a possible BSM scenario is provided by R-parity conserving supersymmetric (SUSY) models in which heavy particles are pair-produced and subsequently undergo cascade decays resulting in leptons, hadronic jets and large missing transverse energy (ETmiss). In this talk we present the search strategies for supersymmetric particles decaying into final states with ETmiss and exactly two isolated leptons. The results are based on the analysis of a data sample with a corresponding integrated luminosity of about 5 fb-1 collected by the ATLAS experiment. One of the dominant irreducible Standard Model backgrounds with a similar search signature as the studied 2-lepton SUSY signals is the diboson + jets production where both bosons decay leptonically. We present a procedure to estimate this background and its systematic uncertainties using a combination of data and simulated events.