Search for Supersymmetry in Events with Large Missing Transverse Momentum, Jets, and at Least One Tau Lepton in 21 fb$^{-1}$ of $\sqrt{s} =$ 8 TeV Proton-Proton Collisions with the ATLAS Detector

A search for supersymmetry in events with large missing transverse momentum, jets, at least one hadronically decaying τ lepton has been performed using 20.7 fb$^{−1}$ of proton-proton collision data at √s = 8 TeV recorded with the ATLAS detector at the Large Hadron Collider. Searches with tau leptons are of interest due to the enhanced branching ratio into taus compared to light leptons in many SUSY models, while being involved due to the differing reconstruction and identification of taus compared to light leptons. No excess above the Standard Model back- ground expectation is observed and a 95% confidence level visible cross section upper limit for new phenomena is set. Exclusion limits are derived in minimal gauge-mediated SUSY breaking models, mSUGRA/CMSSM where parameters are chosen to be comaptible with the mass of the Higgs boson-like particle discovered at the LHC, and in a framework of natural gauge mediation.