Further search for supersymmetry at $\sqrt{s} = 7$ TeV in final states with jets, missing transverse momentum and one isolated lepton

This note presents an update and extension of the search for supersymmetry (SUSY) by the ATLAS experiment at the LHC in proton-proton collisions at a center-of-mass energy $\sqrt{s} = 7$~TeV in final states with jets, missing transverse momentum and one isolated electron or muon. The search is based on all data collected in 2011, with an integrated luminosity of 4.7 \ifb. A new signal region is introduced to be sensitive to decay cascades of SUSY particles with small mass differences. A significant increase in sensitivity is obtained by simultaneously fitting mutually exclusive signal regions, and the shapes of distributions within those regions. Background uncertainties are constrained by fitting to the jet multiplicity distribution in background control regions. Observations remain consistent with Standard Model expectations, and limits are extended on a number of SUSY models.