Fermion Perticle

A Fermion Perticle is an elementary particle that follows Fermi–Dirac statistics and typically has a half-odd-integer particle spin.

• Context:
  • It can (typically) follow Fermi–Dirac statistics, meaning it adheres to certain statistical behaviors in quantum mechanics.
  • It can (often) possess a half-integer spin, such as spin 1/2, which distinguishes it from bosons.
  • It can range from being an elementary particle like an electron to being a composite particle like a proton.
  • It can obey the Pauli Exclusion Principle, meaning no two fermions can occupy the same quantum state simultaneously.
  • It can form the building blocks of matter, as all quarks, leptons, and many atoms and nuclei are fermions.
  • It can possess conserved quantum numbers, such as baryon or lepton numbers, which are crucial in particle physics interactions.
  • It can (typically) be associated with matter, while bosons are generally associated with force carriers.
  • It can display superfluidity or superconductivity under extreme conditions, even though it primarily exhibits fermionic behavior.
  • It can be named after the Italian physicist Enrico Fermi, as coined by English theoretical physicist Paul Dirac.
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• Example(s):
  • Proton that exemplifies a composite fermion made of quarks.
  • Neutron that highlights another composite fermion, crucial in atomic nuclei.
  • Neutrino that showcases the characteristics of a lepton fermion with a very small mass.
  • Electron that demonstrates an elementary particle fermion with a spin of 1/2.
  • ...
• Counter-Example(s):
  • Bosons, which follow Bose–Einstein statistics and can occupy the same quantum state.
  • Photons, which are bosons with integer spin.
• See: Fermi–Dirac Statistics, Spin 1/2, Pauli Exclusion Principle, Quark, Lepton, Composite Particle, Even and Odd, Baryon, Atom.

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References

2024

• (Wikipedia, 2024) ⇒ https://en.wikipedia.org/wiki/Fermion Retrieved:2024-3-12.
  • In particle physics, a fermion is a particle that follows Fermi–Dirac statistics. Generally, it has a half-odd-integer spin: spin, spin, etc. These particles obey the Pauli exclusion principle. Fermions include all quarks and leptons and all composite particles made of an odd number of these, such as all baryons and many atoms and nuclei. Fermions differ from bosons, which obey Bose–Einstein statistics.

    Some fermions are elementary particles (such as electrons), and some are composite particles (such as protons). For example, according to the spin-statistics theorem in relativistic quantum field theory, particles with integer spin are bosons. In contrast, particles with half-integer spin are fermions.

    In addition to the spin characteristic, fermions have another specific property: they possess conserved baryon or lepton quantum numbers. Therefore, what is usually referred to as the spin-statistics relation is, in fact, a spin statistics-quantum number relation. As a consequence of the Pauli exclusion principle, only one fermion can occupy a particular quantum state at a given time. Suppose multiple fermions have the same spatial probability distribution. Then, at least one property of each fermion, such as its spin, must be different. Fermions are usually associated with matter, whereas bosons are generally force carrier particles. However, in the current state of particle physics, the distinction between the two concepts is unclear. Weakly interacting fermions can also display bosonic behavior under extreme conditions. For example, at low temperatures, fermions show superfluidity for uncharged particles and superconductivity for charged particles. Composite fermions, such as protons and neutrons, are the key building blocks of everyday matter. English theoretical physicist Paul Dirac coined the name fermion from the surname of Italian physicist Enrico Fermi.

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