  An inclusive search is performed for supersymmetry in final states containing
jets and an apparent imbalance in transverse momentum, pt[miss], due to the
production of unobserved weakly interacting particles in pp collisions at a
centre-of-mass energy of 8 TeV. The data, recorded with the CMS detector at the
CERN LHC, correspond to an integrated luminosity of 18.5 inverse femtobarns.
The dimensionless kinematic variable alpha[T] is used to discriminate between
events with genuine pt[miss] associated with unobserved particles and spurious
values of pt[miss] arising from jet energy mismeasurements. No excess of event
yields above the expected standard model backgrounds is observed. The results
are interpreted in terms of constraints on the parameter space of several
simplified models of supersymmetry that assume the pair production of top
squarks. The search provides sensitivity to a broad range of top squark decay
modes, including the two-body decay top squark to c chi0, where c is a charm
quark and chi0 is the lightest neutralino, as well as the four-body decay top
squark to b f f' chi0, where b is a bottom quark and f and f' are fermions
produced in the decay of an intermediate off-shell W boson. These modes
dominate in scenarios in which the top squark and lightest neutralino are
nearly degenerate in mass. For these modes, top squarks with masses as large as
260 and 230 GeV are excluded, respectively, for the two- and four-body decays.
