Observation and measurements of vector-boson scattering with ATLAS

The scattering of electroweak bosons tests the gauge structure of the Standard Model and is sensitive to anomalous quartic gauge couplings. In this talk, we present recent results on vector-boson scattering from the ATLAS experiment using proton-proton collisions at $\sqrt{s}=13$ TeV. This includes the observation of $WZ$ and same-sign $WW$ production via vector-boson scattering along with a measurement of $VV$ production in semileptonic final states. If available, measurements of $ZZ$ production via vector-boson scattering will also be presented. The results can be used to constrain new physics that manifests as anomalous electroweak-boson self interactions. Predicted cross sections for electroweak scattering of two same-sign $W$ bosons in association with two jets are compared for a number of Monte Carlo configurations. The sensitivity to the choices of renormalisation and factorisation scales, the Parton Distribution Functions and showering models are studied into detail.