Editing Quantum number (section)

==Elementary particles==
{{For|a more complete description of the quantum states of elementary particles|Standard model|Flavour (particle physics)}}

[[Elementary particle]]s contain many quantum numbers which are usually said to be intrinsic to them. However, it should be understood that the elementary particles are [[quantum state]]s of the [[standard model]] of [[particle physics]], and hence the quantum numbers of these particles bear the same relation to the [[Hamiltonian (quantum mechanics)|Hamiltonian]] of this model as the quantum numbers of the [[Bohr atom]] does to its [[Hamiltonian (quantum mechanics)|Hamiltonian]]. In other words, each quantum number denotes a symmetry of the problem. It is more useful in [[quantum field theory]] to distinguish between spacetime and internal symmetries.

Typical quantum numbers related to [[spacetime symmetries]] are spin (related to rotational symmetry), the [[parity (physics)|parity]], [[C-parity]] and [[T-parity]] (related to the [[Poincaré symmetry]] of [[spacetime]]). Typical '''internal symmetries'''{{clarify|date=August 2016}} are [[lepton number]] and [[baryon number]] or the [[electric charge]]. (For a full list of quantum numbers of this kind see the article on [[flavour (particle physics)|flavour]].)