Vector boson scattering in a final state with two jets and two same-sign leptons

A measurement of vector boson scattering in pp collisions at $\sqrt{s}=8~\mathrm{Te\kern -0.1em V}$ is presented. The data sample corresponds to an integrated luminosity of 19.4 fb$^{-1}$ collected by the CMS detector. Candidate events are selected with exactly two leptons with the same charge, two jets with large rapidity separation, and moderate missing transverse energy. The signal region is dominated by electroweak same-sign $\mathrm{W}$ pair production. The observation agrees with the standard model hypothesis. The observed significance for vector boson scattering is 2.0$\sigma$, where a significance of 3.1$\sigma$ is expected. Cross section measurements of the $\mathrm{W}^{\pm}\mathrm{W}^{\pm}$ and $\mathrm{W}\mathrm{Z}$ processes in a vector boson scattering-like 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.