  A study of vector boson scattering in pp collisions at a center-of-mass
energy of 8 TeV is presented. The data sample corresponds to an integrated
luminosity of 19.4 inverse femtobarns collected with the CMS detector.
Candidate events are selected with exactly two leptons of the same charge, two
jets with large rapidity separation and dijet mass, and moderate missing
transverse energy. The signal region is expected to be dominated by electroweak
same-sign W-boson pair production. The observation agrees with the standard
model prediction. The observed significance is 2.0 standard deviations, where a
significance of 3.1 standard deviations is expected based on the standard
model. Cross section measurements for W+/- W+/- and WZ processes in the
fiducial region are reported. Bounds on the structure of quartic vector-boson
interactions are given in the framework of dimension-eight effective field
theory operators, as well as limits on the production of doubly-charged Higgs
bosons.
