A constituent quark is a

current quark Current quarks (also called naked quarks or bare quarks) are a description of valence quarks as the cores of the quark particles that are the invariable parts of a hadron: their non-virtual ("real" or permanent) quarks with their surrounding "cov ...

with a notional "covering" induced by the

renormalization group In theoretical physics, the renormalization group (RG) is a formal apparatus that allows systematic investigation of the changes of a physical system as viewed at different scales. In particle physics, it reflects the changes in the underlying p ...

. In the low-energy limit of

QCD In theoretical physics Theoretical physics is a branch of physics that employs mathematical models and abstractions of physical objects and systems to rationalize, explain, and predict List of natural phenomena, natural phenomena. This is in ...

, a description by means of

perturbation theory In mathematics and applied mathematics, perturbation theory comprises methods for finding an approximate solution to a problem, by starting from the exact solution of a related, simpler problem. A critical feature of the technique is a middle ...

is not possible: Here, no

asymptotic freedom In quantum field theory, asymptotic freedom is a property of some gauge theory, gauge theories that causes interactions between particles to become asymptotically weaker as the energy scale increases and the corresponding length scale decreases. (A ...

exists, but collective interactions between

valence quark In particle physics, the quark model is a classification scheme for hadrons in terms of their valence quarks—the quarks and antiquarks that give rise to the quantum numbers of the hadrons. The quark model underlies Flavour (particle physics), ...

s and sea quarks gain strongly in significance. Part of the effects of virtual quarks and virtual gluons in the "sea" can be assigned to a

quark A quark () is a type of elementary particle and a fundamental constituent of matter. Quarks combine to form composite particles called hadrons, the most stable of which are protons and neutrons, the components of atomic nucleus, atomic nuclei ...

so well that the term "constituent quark" can serve as an effective description of the low-energy system. Constituent quarks appear like "dressed" current quarks, i.e. current quarks surrounded by a cloud of virtual quarks and gluons. This cloud, in the end, underlies the large constituent-quark masses. ;Definition: Constituent quarks are valence quarks for which the correlations for the description of hadrons by means of gluons and sea-quarks are put into effective quark masses of these valence quarks. The effective quark mass is called constituent quark mass. Hadrons consist of "glued" constituent quarks.

Binding energy

The

quantum chromodynamic binding energy In physics, a quantum (: quanta) is the minimum amount of any physical entity (physical property) involved in an interaction. The fundamental notion that a property can be "quantized" is referred to as "the hypothesis of quantization". This me ...

of a valence quark in a hadron is the amount of energy required to make the hadron spontaneously emit a meson containing the valence quark. This is the same as the constituent-quark mass. Note that the following values are model-dependent.

References

{{particle-stub Quarks