Proceeding for LHCP2014 Poster: Search for direct pair production of the
top squark in all-hadronic final states in proton-proton collisions at
sβ=8 TeV with the ATLAS detector
The results of a search for direct pair production of the scalar partner to
the top quark using an integrated luminosity of 20.1fbβ1 of
proton-proton collision data at sβ=8 TeV recorded with the ATLAS
detector at the LHC are reported. The top squark is assumed to decay via
t~βtΟ~β10β or t~βbΟ~β1Β±ββbW(β)Ο~β10β, where Ο~β10β (Ο~β1Β±β)
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 t~βtΟ~β10β. For a branching
fraction of 100%, top squark masses in the range 270-645 GeV are excluded for
Ο~β10β masses below 30 GeV. For a branching fraction of 50% to
either t~βtΟ~β10β or t~βbΟ~β1Β±β, and assuming the Ο~β1Β±β mass to be
twice the Ο~β10β mass, top squark masses in the range 250-550
GeV are excluded for Ο~β10β masses below 60 GeV.Comment: 5 pages, 6 figues. Proceeding for the poster present at LHCP 201