The Standard Model of Particle Physics

- Overview

The Standard Model of particle physics is scientists' current best theory for describing the most fundamental building blocks of the universe. It explains how particles called quarks (which make up protons and neutrons) and leptons (which include electrons) make up all known matter. It also explains how force-carrying particles belonging to the broader group of bosons affect quarks and leptons. 

The Standard Model explains three of the four fundamental forces that govern the universe: the electromagnetic force, the strong force, and the weak force. Electromagnetism is carried by photons and involves the interaction of electric and magnetic fields. The strong force carried by gluons holds atomic nuclei together, making them stable. The weak force carried by the W and Z bosons causes nuclear reactions that have powered the Sun and other stars for billions of years. The fourth fundamental force is gravity, which cannot be adequately explained by the Standard Model. 

Despite its success in explaining the universe, the Standard Model does have limitations. For example, the Higgs boson provides mass to quarks, charged leptons (such as electrons), and the W and Z bosons. However, we don't yet know whether the Higgs boson also provides mass to neutrinos - ghostly particles that rarely interact with other matter in the universe. Furthermore, physicists know that about 95 percent of the universe is not made of ordinary matter as we know it. Instead, most of the universe is made up of dark matter and dark energy that don't fit the Standard Model. 

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