Effectively going beyond the Standard Model: Combined interpretations of Higgs boson and electroweak measurements from the ATLAS experiment

The thesis presents novel interpretations of the data collected by the ATLAS experiment in the context of the Standard Model Effective Field Theory (SMEFT). The interpretation of the combined kinematic measurements of Higgs boson production from the $H\rightarrow \gamma\gamma$, $H→4l$, and $VH,H\rightarrow bb$ channels presents the first opportunity to constrain the Higgs sector of the SMEFT, constraining ten parameters. The SMEFT interpretation of the Higgs boson measurements is expanded with additional leading Higgs boson decay channels, including $H\rightarrow\tau \tau$ and $H\rightarrow WW^{*}\rightarrow l\nu l\nu$ and as well as rare Higgs boson decay channels such as $H\rightarrow \mu\mu$ and $H\rightarrow Z\gamma$ resulting in a constraint on nineteen parameters. The unified SMEFT model for Higgs boson production in the $H\rightarrow WW^{*}\rightarrow l\nu l\nu$ channel and electroweak production of a pair of W bosons discusses a joint interpretation of the Higgs and the electroweak sector allowing to constrain eight parameters. The SMEFT interpretation of combined Higgs boson measurements with the electroweak sector measurements from ATLAS and LEP/SLD demonstrate the global utility of SMEFT and constraints twenty-eight parameters. Finally, the SMEFT constraints are also matched to the Two Higgs Doublet model, demonstrating the SMEFT as an intermediate step between the Standard Model and more complex models of new physics.