Particle physics and the standard model

The standard model in physics
In the past few decades, physicists have used ever more powerful particle accelerators to collide particles at higher and higher energies. They have discovered many new particles and have created a standard model that explains the new physics. The model is a consensus theory of particles, matter and antimatter, particle interactions (or forces), and quantum physics. Particles are classified according to their electric charge, how they interact with each other, and family (or “generation”). Read the text aloud Show Gravitational waves
In the standard model, there are two kinds of elementary particles: fermions and bosons. All particles in the universe ultimately are made up of fermions. Read the text aloud
Quarks are particles that are smaller than protons or neutrons. There are six different quarks that come in three pairs: up and down, charm and strange, and top and bottom. Quarks are never seen directly or found in isolation but can only be found inside hadrons, such as protons or neutrons. Baryons, including neutrons and protons, are composed of three quarks. Mesons are composed of a quark and an antiquark. Quarks are affected by the strong nuclear force. Read the text aloud
Leptons are the other category of fermion. Electrons and neutrinos are two examples of leptons. Leptons are not affected by the strong nuclear force but obey the Pauli exclusion principle. Read the text aloud
Quarks and leptons are grouped into three different families or “generations.” Everyday matter is made up from the lowest mass group of particles, comprising the electron, the electron neutrino, and the up and down quarks. The two higher mass groups are called “exotic” because they are usually only seen in very high energy conditions, such as inside a particle accelerator. Read the text aloud
In the standard model every particle also has an antimatter opposite, an antiparticle with the same mass and other properties but opposite charge. The positron is the antimatter twin of the electron and has positive charge. Neutral particles are their own antiparticle, because they are electrically neutral. When a particle and its antiparticle twin collide in pair annihilation, a large amount of energy is released. Read the text aloud
Bosons are elementary particles that mediate (or cause) forces to happen. In the standard model, there is at least one boson for each of the four forces of nature. Read the text aloud Show Higgs boson

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