Search for direct pair production of the top squark in all-hadronic final states in proton-proton collisions at $\\sqrts=8$ TeV with the ATLAS detector
Journal
JHEP
Journal Volume
09
Pages
015
Date Issued
2014
Author(s)
Aad, Georges
Abstract
CERN-LHC. The results of a search for direct pair production of the scalar partner to the top quark using an integrated luminosity of 20.1 fb^{-1} of proton-proton collision data at sqrt(s) = 8 TeV recorded with the ATLAS detector at the LHC are reported. The top squark is assumed to decay via stop --> t chi1^0 or stop --> b chi1^{+/-} --> b W^{(*)} chi1^0, where chi1^0 (chi1^{+/-}) denotes the lightest neutralino (chargino) in supersymmetric models. The search targets a fully-hadronic final state in events with four or more jets and large missing transverse momentum. No significant excess over the Standard Model background prediction is observed, and exclusion limits are reported in terms of the top squark and neutralino masses and as a function of the branching fraction of stop --> t chi1^0. For a branching fraction of 100%, top squark masses in the range 270-645 GeV are excluded for chi1^0 masses below 30 GeV. For a branching fraction of 50% to either stop --> t chi1^0 or stop --> b chi1^{+/-}, and assuming the chi1^{+/-} mass to be twice the chi1^0 mass, top squark masses in the range 250-550 GeV are excluded for chi1^0 masses below 60 GeV.
Type
journal article