Constraining anomalous couplings in the gauge-Higgs sector at high-energy colliders

Abstract

Several physical phenomena suggest that the Standard Model is not the ultimate theory possible for describing Nature, and looking for deviations from the theory prediction might be a hint for physics beyond the Standard Model. Nevertheless, the lack of tantalising evidence for new resonant physics, along with our ignorance of the energy scale at which such physics should arise, require us to improve current precision measurements to further test the Standard Model.

It is possible to treat the Standard Model as an Effective Field Theory, valid up to a high cut-off energy scale above the electroweak scale, equipped with a new set of Lorentz structures, the so-called anomalous couplings, that extend and parametrise with modified couplings the vertices allowed by the Standard Model. The interactions between the Higgs and the gauge bosons are thought to be a promising avenue to scrutinise the Standard Model for any new physics effects.

In this Thesis we explore the gauge-Higgs sector to segregate the anomalous couplings that arise in viewing the Standard Model as an Effective Field Theory. In doing so, we investigate the capability of current and future experiments at constraining said anomalous couplings through standard processes involving gauge-Higgs interactions that might shed light on what potentially lies beyond the Standard Model.

We study the so-called golden channel in the environment of the High-Luminosity Large Hadron Collider, as well as the Higgs-strahlung and Z-boson fusion processes at the high-energy stages of both the International Linear Collider and the Compact Linear Collider. These channels allow us to project stringent bounds on anomalous couplings in the gauge-Higgs sector that can be probed at high-energy colliders.