  We employ the ATLAS search results for events containing jets and large
missing transverse momentum, corresponding to an integrated luminosity of 1
fb^{-1}, to investigate the constrained minimal supersymmetric model (CMSSM)
with b-\tau Yukawa coupling unification. In this scenario, one of the stops is
the next-to-lightest supersymmetric particle (NLSP), which co-annihilates with
the lightest (LSP) neutralino to yield the desired dark matter relic abundance.
The NLSP stop, here taken to be lighter than the top quark, is slightly (<~
20%-30%) heavier than the LSP neutralino, and it primarily decays into the LSP
and a charm quark. We find that the multi-jets and monojet ATLAS searches are
sensitive to this scenario if the stop pair production is accompanied by a hard
QCD jet. The excluded limit for the NLSP stop mass from the ATLAS data can
reach 160 GeV in the coannihilation region, with mass below 140 GeV essentially
excluded. A significant region of the parameter space corresponding to large
m_0 values, 8 TeV<~ m_0<~ 16 TeV, is excluded by our analysis. For LSP
neutralino mass ~ 100 GeV, the LHC constraints in some cases on the
spin-dependent (spin-independent) neutralino-nucleon cross section are
significantly more stringent than the current and expected bounds from Xenon,
CDMS and IceCube.
