Search for a Three Lepton and Missing Transverse Energy Signature of Supersymmetry Using a Multivariate Analysis

A search for evidence of supersymmetry with a three lepton and missing transverse energy signature is presented. This signature is a possible final state from the associated production of a chargino and a neutralino, two particles predicted by supersymmetry. The study is performed on 2:06 fb-1 of 7 TeV center of mass energy proton-proton collisions, recorded with the ATLAS experiment at the Large Hadron Collider in 2011. A multivariate analysis is utilized, implementing a boosted decision tree classi- er using lepton pT , missing transverse energy, dilepton mass, and the razor variable R as inputs. No significant excess over the Standard Model prediction is observed, and upper limits are placed on the cross section times branching ratio of simplifiied models across a mass parameter space.