Editing Covalent bond (section)

== Analogous effect in nuclear systems ==
An analogous effect to covalent binding is believed to occur in some nuclear systems, with the difference that the shared fermions are [[quarks]] rather than electrons.<ref>
{{cite journal
 |last1=Brodsky |first1=S. J.
 |title=Novel Features of Nuclear Chromodynamics |url=https://inspirehep.net/files/081b94935ae48c72c2d8d382b0d3da3c
 |journal=The European Physical Journal A
 |volume=53 |issue=3
 |year=2017
 |page=48
 |doi=10.1140/epja/i2017-12234-5
 |bibcode=2017EPJA...53...48B
 |osti=1341388
 |s2cid=126305939
 }}</ref> [[Particle physics|High energy]] [[proton]]-proton [[scattering]] [[Cross section (physics)|cross-section]] indicates that quark interchange of either u or d quarks is the dominant process of the [[nuclear force]] at short distance. In particular, it dominates over the [[Yukawa interaction]] where a [[meson]] is exchanged.<ref>
{{cite journal
 |last1=Brodsky |first1=S. J.
 |last2=Mueller |first2=A. H.
 |title=Using Nuclei to Probe Hadronization in QCD |url=https://inspirehep.net/files/265dea42f5f8eff75f4a59300d6f9157
 |journal=Physics Letters B
 |volume=206
 |year=1988
 |issue=4
 |page=685
 |doi=10.1016/0370-2693(88)90719-8
 |bibcode=1988PhLB..206..685B
 |osti=1448604
 }}</ref> Therefore, covalent binding by quark interchange is expected to be the dominating mechanism of nuclear binding at small distance when the bound [[hadrons]] have covalence quarks in common.<ref>
{{cite journal
 |last1=Bashkanova |first1=M.
 |last2=Brodsky |first2=S. J.
 |last3=Clement |first3=H.
 |title=Novel Six-Quark Hidden-Color Dibaryon States in QCD
 |journal=Physics Letters B
 |volume=727
 |year=2013
 |issue=4–5
 |page=438
 |doi=10.1016/j.physletb.2013.10.059
 |arxiv = 1308.6404
 |bibcode=2013PhLB..727..438B
 |s2cid=30153514
 }}</ref>