Search for R-parity violating Supersymmetry in multi-lepton final states with the ATLAS detector

The benchmark scenario BC1 is an example of an R-parity violating supersymmetric (SUSY) model with one lepton number violating coupling, lambda121. Its lightest supersymmetric particle is the stau1, which decays promptly into multiple charged leptons and a neutrino. In this thesis prior phenomenological studies of the parameter space surrounding BC1 were extended. To search for evidence of such models, a final state with four leptons and moderate missing transverse momentum was analyzed, using the first 2.06 fb-1 of data recorded by the ATLAS experiment at a center-of-mass energy of 7 TeV in 2011. Since no excess of events was found in the signal region, 95% confidence level (CLS) upper limits were set on the visible cross section of new physics. The same results were interpreted in terms of BC1-like models, resulting in an exclusion region given by m1/2 less than about 800 GeV and tan beta less than about 40.