  A first search for pair production of dark matter candidates through vector
boson fusion in proton-proton collisions at sqrt(s) = 8 TeV is performed with
the CMS detector. The vector boson fusion topology enhances missing transverse
momentum, providing a way to probe supersymmetry also in the case of a
compressed mass spectrum. The data sample corresponds to an integrated
luminosity of 18.5 inverse femtobarns recorded by the CMS experiment. The
observed dijet mass spectrum is consistent with the standard model expectation.
In an effective field theory, dark matter masses are explored as a function of
contact interaction strength. The most stringent limit on bottom squark
production with mass below 315 GeV is also reported, assuming a 5 GeV mass
difference with respect to the lightest neutralino.
