  Results are presented from a search for new decaying massive particles whose
presence is inferred from an imbalance in transverse momentum and which are
produced in association with a single top quark that decays into a bottom quark
and two light quarks. The measurement is performed using 19.7 inverse
femtobarns of data from proton-proton collisions at a center-of-mass energy of
8 TeV, collected with the CMS detector at the CERN LHC. No deviations from the
standard model predictions are observed and lower limits are set on the masses
of new invisible bosons. In particular, scalar and vector particles, with
masses below 330 and 650 GeV, respectively, are excluded at 95% confidence
level, thus substantially extending a previous limit published by the CDF
Collaboration.
