Constraints on Anomalous Quartic Gauge Couplings in the Electroweak Gauge Boson Scattering WZjj Final State with the ATLAS Detector

This work analyses the electroweak gauge boson scattering final state $W^{\pm} Z_{j j}$ to constrain the anomalous quartic electroweak gauge couplings $\alpha_{4}$ and $\alpha_{5}$. They are introduced within an effective field theory ansatz and parametrize low energy effects of possible theories beyond the Standard Model of particle physics in a model independent manner. This is done, because it is assumed that the Standard Model is a low energy approximation of a so far unknown theory. The analysis is performed with the recorded ATLAS data from proton-proton collisions in 2012 with a center-of-mass energy of $\sqrt{s}=8 \mathrm{TeV}$ and an integrated luminosity of $\int \mathcal{L} \mathrm{d} t=20.281 \mathrm{fb}^{-1}$. Expected one-dimensional upper limits at $95 \%$ confidence level for $\alpha_{4}$ and $\alpha_{5}$ are determined for an optimized event selection to $0.29$ for $\alpha_{4}$ and $0.30$ for $\alpha_{5}$. The observed constraints for the same selection are less restrictive due to an excess in data, they amount to $0.53$ for $\alpha_{4}$ and $0.52$ for $\alpha_{5}$.