Hunting Asymmetric Top Squark Decays

In the irreducible natural supersymmetric spectrum, top squarks have comparable branching fractions to chargino-bottom and neutralino-top final states in the vast bulk of parameter space, provided only that both decay modes are kinematically accessible. The total top squark pair branching fractions into tt$+$MET (MET$=$missing transverse energy) can therefore be reduced, thus limiting the reach of traditional top squark searches. A new top squark search targeting the asymmetric final state tb$+$MET, which can restore sensitivity to natural top squarks in the 7, 8 and 14 TeV LHC runs will be presented. A new variable, topness, will be introduced, which efficiently suppresses the dominant top backgrounds to semileptonic top partner searches. The utility of topness in both the asymmetric search channel and traditional tt$+$MET searches will be compared and be shown to match or outperform existing variables.