PhD defense Robin Hayes

The Standard Model (SM) is the governing theory of particle physics. Although its predictions are in excellent agreement with experimental observations, it does not provide a full picture of the physical universe. The Higgs boson is the SM's most recently-discovered particle and a crucial ingredient of the theory. Measuring any deviation between its observed and expected properties could pave the way toward a more complete theory. 

This thesis describes a study of the Higgs boson using proton-proton collisions at the Large Hadron Collider. The collision data was collected between 2015 and 2018 by the ATLAS detector. This research identifies the Higgs boson using its decay to two W bosons, H->WW*. It examines Higgs boson production via gluon fusion and vector boson fusion, making it sensitive to the Higgs boson's interactions with both heavy quarks and vector bosons. It results in the first observation of vector boson fusion production followed by H->WW* decay and measurements of Higgs boson cross-sections inclusively and across various kinematic regions. The measurements are made with unprecedented precision in this decay channel, and are compatible with the SM prediction.