Search for direct top squark pair production in final states with one isolated lepton

Motivated by natural SUSY, a search for supersymmetric top quark pair production in final states with one isolated lepton, jets and missing transverse momentum in $\sqrt{s}=8$~TeV $pp$ collisions using 20.3~$\rm fb^{-1}$ of data from the ATLAS experiment, is presented. Five different decay scenarios for the supersymmetric top quark (stop) are considered. As the data are in agreement with predictions from the Standard Model, the measurements are translated into 95\% C.L. upper limits on the masses of the stop and the lightest supersymmetric particle (LSP) in various supersymmetric scenarios. The sensitivity to a limited number of pMSSM models, in which the stop can decay into heavy neutralinos and charginos, is also presented.