Editing Quark (section)

=== Mass ===
[[Image:Quark masses as balls.svg|thumb|Current quark masses for all six flavors in comparison, as [[w:ball (mathematics)|balls]] of proportional volumes. [[Proton]] (gray) and [[electron]]&nbsp;(red) are shown in bottom left corner for scale.]]
{{See also|Invariant mass}}
Two terms are used in referring to a quark's mass: ''[[current quark]] mass'' refers to the mass of a quark by itself, while ''[[constituent quark]] mass'' refers to the current quark mass plus the mass of the [[gluon]] [[quantum field theory|particle field]] surrounding the quark.<ref>
{{cite book
 |author=A. Watson
 |title=The Quantum Quark
 |pages=285–286
 |publisher=[[Cambridge University Press]]
 |year=2004
 |isbn=978-0-521-82907-6
}}</ref> These masses typically have very different values. Most of a hadron's mass comes from the gluons that bind the constituent quarks together, rather than from the quarks themselves. While gluons are inherently massless, they possess energy – more specifically, [[quantum chromodynamics binding energy]] (QCBE) – and it is this that contributes so greatly to the overall mass of the hadron (see [[mass in special relativity]]). For example, a proton has a mass of approximately {{val|938|ul=MeV/c2}}, of which the rest mass of its three valence quarks only contributes about {{val|9|u=MeV/c2}}; much of the remainder can be attributed to the field energy of the gluons<ref name=PDGQuarks/><ref>
{{cite book
 |author1=W. Weise
 |author2=A. M. Green
 |title=Quarks and Nuclei
 |pages=65–66
 |publisher=[[World Scientific]]
 |year=1984
 |isbn=978-9971-966-61-4
}}</ref> (see [[chiral symmetry breaking]]). The Standard Model posits that elementary particles derive their masses from the [[Higgs mechanism]], which is associated to the [[Higgs boson]]. It is hoped that further research into the reasons for the top quark's large mass of ~{{val|173|u=GeV/c2}}, almost the mass of a gold atom,<ref name=PDGQuarks/><ref>
{{cite book
 |author=D. McMahon
 |title=Quantum Field Theory Demystified
 |url=https://archive.org/details/quantumfieldtheo00mcma_095
 |url-access=limited
 |page=[https://archive.org/details/quantumfieldtheo00mcma_095/page/n35 17]
 |publisher=[[McGraw–Hill]]
 |year=2008
 |isbn=978-0-07-154382-8
}}</ref> might reveal more about the origin of the mass of quarks and other elementary particles.<ref>
{{cite book
 |author=S. G. Roth
 |title=Precision Electroweak Physics at Electron–Positron Colliders
 |page=VI
 |publisher=[[Springer Science+Business Media|Springer]]
 |year=2007
 |isbn=978-3-540-35164-1
}}</ref>