ABSTRACT
The SM of elementary particle physics is a renormalisable gauge theory of the strong, EM and weak interactions, which has been confirmed experimentally. It incorporates both bosons, as mediators of such interactions, and fermions, as matter states upon which these act. Crucially, it also embeds the so-called Higgs mechanism, which enables the unification of the last two types of interactions into a single one, the EW force, generating as a by-product the masses of all such bosonic (except the photon) and fermionic (except the neutrinos) states. The SM makes genuine theoretical predictions in both such sectors, which have been eventually confirmed by experiment. On the one hand, it predicted the existence of the massive weak gauge bosons, the W ± $ W^\pm $ https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315367903/c2682a74-a79a-4ae8-b55f-fb03894f6bcd/content/inline-math1_1.tif"/> and Z states, and their mass and coupling relations. On the other hand, it predicted the existence of a third generation of leptons and quarks to account for the observed CP violation of EW interactions, which was confirmed by the discovery of the τ $ \tau $ https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9781315367903/c2682a74-a79a-4ae8-b55f-fb03894f6bcd/content/inline-math1_2.tif"/> (tau) lepton plus b (bottom) and t (top) quarks. Its most crucial component, the self-interacting Higgs boson, which is spinless (i.e., a scalar) unlike the gauge bosons which have spin one (i.e., they are vectors), emerging from the spontaneous breaking of an initial EW symmetry, also seems to have been found.
