Quark

:For other uses of this term, see: Quark (disambiguation)

Confinement and quark properties

Every subatomic particle is completely described by a small set of quantum numbers such as its spin J, parity P, and mass m. Usually these properties are directly determined by experiments. However, confinement makes it impossible to measure these properties of quarks. Instead, they must be inferred from measurable properties of the composite particles which are made up of quarks. Such inferences are easiest to make for certain additive quantum numbers called flavours.

Related Topics:
Subatomic particle - Quantum number - Spin - Parity - Flavour

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The composite particles made of quarks and antiquarks are the hadrons. These include the mesons which get their quantum numbers from a quark and an antiquark, and the baryons, which get theirs from three quarks. The quarks (and antiquarks) which impart quantum numbers to hadrons are called valence quarks. Apart from these, any hadron may contain an indefinite number of virtual quarks, antiquarks and gluons which together contribute nothing to their quantum numbers. Such virtual quarks are called sea quarks.

Related Topics:
Hadron - Meson - Baryon - Virtual

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