Search for strongly interacting supersymmetric particles decaying to final states with an isolated lepton with the ATLAS detector at the LHC

Two analyses searching for squarks and gluinos which decay into
final states with multiple jets, an isolated electron or muon and a
large missing transverse energy are presented. Both rely on data
taken by the ATLAS detector in pp collisions at a center-of-mass
energy of 8 TeV at the LHC during 2012. The first analysis uses a
subset of 5.8 fb-1 of this dataset, the other analysis uses the
full statistics of 20.3 fb-1. Both analysis share the same methods
regarding the triggers and the background estimation techniques.
The two dominant backgrounds are ttbar and W+jets production. The
ttbar and the W+jets backgrounds are estimated in a
semi-data-driven method. The minor QCD multi-jet background is
estimated in an entirely data-driven method. The final background
estimates in the analyses are derived in a profile-log-likelihood
fit. None of the analyses sees an excess beyond Standard Model
expectations. The analysis of the partial dataset derives limits in
a MSUGRA/CMSSM model with parameters A_0=0, tan(beta) = 10 and mu
> 0 and excludes squarks and gluinos with masses below 1.2 TeV
for equal squark and gluino masses. The analysis of the full
dataset derives limits in simplified models and in a MSUGRA/CMSSM
model with parameters A_0=-2 m_0, tan(beta) = 30 and mu > 0.
Gluinos (squarks) with masses below 1.2 TeV (750 GeV) can be
excluded for vanishing LSP masses in simplified models. Gluino
masses below 1.2 TeV can be excluded for every m_0 value in the
MSUGRA/CMSSM model.