The Higgs Boson and the Standard Model of Particle Physics

Abstract

The Standard Model of particle physics (SM) [1] is the pillar on which the current understanding of the subatomic world is based. It describes the elementary particles and their fundamental interactions in the context of a Lorentz-invariant and renormalizable quantum field theory. The theoretical framework of the SM is corroborated by an extensive set of experimental measurements, of which the last is the discovery of a particle compatible with the Higgs boson by the ATLAS and CMS Collaborations at the CERN LHC in June 2012 [2, 3, 4]. A brief theoretical introduction to the SM is given in Sect. 1.1, emphasizing the electroweak symmetry breaking mechanism (EWSB) in Sect. 1.1.2. This process ensures that elementary particles acquire mass while respecting the gauge symmetries of the SM by introducing an additional scalar field to the SM Lagrangian: the Higgs boson, a long-sought particle originally postulated in the second half of the XX century, but experimentally detected only 50 years later. More details about the properties and the phenomenology of this particle at hadron colliders are given in Sect. 1.2. The chapter closes in Sect. 1.3, with the description of the Higgs boson decay into four leptons, being it the channel studied in this work.