12.12 The Standard Model
The standard model is the collection of theories that describe the smallest experimentally observed particles of matter and interaction between energy and matter. Three categories of particles form the standard model are shown in Fig. 12.8. Matter, which makes up only of the universe is composed of quarks and leptons. The fundamental bosons provide three forces: electromagnetism, the strong nuclear force and the weak nuclear force.
The Higgs's boson provides an explanation for how the other particles get mass.
This model is still considered incomplete. Currently, it is unable to explain many important features of the known universe such as: (i) gravity (ii) dark matter ( of the universe) (iii) dark energy ( of the universe).