Editing Pauli exclusion principle (section)

== Overview ==
The Pauli exclusion principle describes the behavior of all [[fermion]]s (particles with half-integer [[Spin (physics)|spin]]), while [[boson]]s (particles with integer spin) are subject to other principles. Fermions include [[elementary particle]]s such as [[quark]]s, [[electron]]s and [[neutrino]]s. Additionally, [[baryon]]s such as [[proton]]s and [[neutron]]s ([[subatomic particle]]s composed from three quarks) and some [[atom]]s (such as [[helium-3]]) are fermions, and are therefore described by the Pauli exclusion principle as well. Atoms can have different overall spin, which determines whether they are fermions or bosons: for example, [[helium-3]] has spin 1/2 and is therefore a fermion, whereas [[helium-4]] has spin 0 and is a boson.<ref name="Krane1987">{{cite book|author=Kenneth S. Krane|title=Introductory Nuclear Physics|date=5 November 1987|publisher=Wiley|isbn=978-0-471-80553-3}}</ref>{{rp|123–125}} The Pauli exclusion principle underpins many properties of everyday matter, from its large-scale stability to the [[periodic table|chemical behavior of atoms]].

Half-integer spin means that the intrinsic [[angular momentum]] value of fermions is <math>\hbar = h/2\pi</math> ([[reduced Planck constant]]) times a [[half-integer]] (1/2, 3/2, 5/2, etc.). In the theory of [[quantum mechanics]], fermions are described by [[identical particles|antisymmetric states]]. In contrast, particles with integer spin (bosons) have symmetric wave functions and may share the same quantum states. Bosons include the [[photon]], the [[Cooper pairs]] which are responsible for [[superconductivity]], and the [[W and Z bosons]]. Fermions take their name from the [[Fermi–Dirac statistics|Fermi–Dirac statistical distribution]], which they obey, and bosons take theirs from the [[Bose–Einstein statistics|Bose–Einstein distribution]].