The Standard Model is a theory that describes the fundamental particles and forces that make up the universe. It is the most widely accepted theory of particle physics and has been developed over several decades by many scientists worldwide . The Standard Model classifies all known elementary particles and describes three of the four known fundamental forces in the universe: the electromagnetic, weak, and strong interactions . It does not include gravity, which is described by the theory of general relativity.
The Standard Model is based on the idea that all matter is made up of particles called fermions. Fermions are divided into two categories: quarks and leptons. Quarks are the building blocks of protons and neutrons, which make up the nucleus of an atom. Leptons include electrons, which orbit the nucleus of an atom .
The Standard Model also describes the bosons, which are particles that mediate the fundamental forces. The photon is the boson that mediates the electromagnetic force, while the W and Z bosons mediate the weak force. The gluon mediates the strong force, which holds quarks together inside protons and neutrons .
The Standard Model is a quantum field theory, which means that it describes particles as excitations of fields that permeate space and time. These fields are described by mathematical equations, and the excitations of these fields are the particles that we observe .
The Standard Model has been very successful in predicting the results of experiments. For example, it predicted the existence of the W and Z bosons, which were discovered in 1983 at CERN . In 2012, the discovery of the Higgs boson at CERN provided further evidence for the Standard Model . However, the Standard Model is not a complete theory of fundamental interactions. It leaves some physical phenomena unexplained, such as baryon asymmetry, dark matter, and neutrino oscillations . It also does not incorporate the full theory of gravitation as described by general relativity.
Despite its limitations, the Standard Model is a remarkable achievement of human understanding of the universe. It has provided a framework for understanding the fundamental particles and forces that make up the universe, and it has led to many technological advances, such as the development of the World Wide Web at CERN .