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Concept
Current quark
Résumé
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, with their non-virtual ("real" or permanent) quarks with their surrounding "covering" of evanescent gluons and virtual quarks imagined stripped away. In quantum chromodynamics, the mass of the current quarks is called the current quark mass, as opposed to the much larger mass of the composite particle which is carried in the gluon and virtual quark covering. The heavier quarks
are large enough for their substantial masses to predominate over the combined mass of their virtual-particle "dressing" or covering, but the lighter quarks
masses are overwhelmed by their evanescent covering's mass-energy; the light quarks' core masses are such a small fraction of the covering that the actual mass values are difficult to infer with any accuracy (hence, the data listed below for the light quarks are fraught with caveats).
The constituent quark, in contrast, is a combination of both the "naked" current quark and its "dressing" of evanescent gluons and virtual quarks. For the lighter quarks, the mass of each constituent quark is approximately 1 /3 of the average mass of the proton and neutron, with a little extra mass fudged in for the strange quark.
Since it is not physically possible even at solar-interior temperatures to "strip naked" any quark of its covering, it is a matter of legitimate doubt whether current quarks are actual or real, or merely a convenient but unrealistic and abstract notion. High energy particle accelerators provide a demonstration that the idea of a "naked quark" is in some sense real: If the current quark imbedded in one constituent quark is hit inside its covering with large momentum, the current quark accelerates through its evanescent covering and leaves it behind, at least temporarily producing a "naked" or undressed quark, showing that to some extent the idea is realistic (see glueball for speculations about what happens to the dressing of virtual particles that gets left behind).
Source officielle
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