Another brick in the Higgs: the composite Higgs scenario

Abstract

The Standard Model (SM) of particle physics has had numerous successes in predicting the results of experiments. Despite this, most particle theorists believe it is not the final theory for the fundamental interactions but an effective theory valid only at some low energy scale. This means that there should be physics beyond the SM (BSM). One of the reasons for this belief is the hierarchy problem, i.e., why the Higgs mass is so much lower than the Planck scale. There are a few solutions to this problem, such as supersymmetry, extra dimensions, and the Composite Higgs. The composite Higgs is one of the most explored solutions to the hierarchy problem nowadays. This model extends the SM symmetries and generates the Higgs field as a composite pseudo-Nambu-Goldstone Boson generated by a symmetry breaking. This breaking can generate several Higgs fields, such as singlets and doublets. This thesis takes a introductory approach to the Composite Higgs Model, with a primary focus on the model’s construction and the Minimal Composite Higgs as a prime example. The first chapter defines and discusses the Hierarchy Problem. The second chapter provides a thorough review of the Higgs mechanism, starting from the basics of gauge symmetry invariance and progressing to Electroweak Symmetry Breaking and the masses of gauge bosons. Chapter three delves into the formal discussions surrounding the Higgs mechanism from a group theory perspective. Finally, chapter four presents the composite Higgs construction in detail, with the minimal composite Higgs serving as a concrete example.