Editing List of particles (section)

=== Hadrons ===
[[Hadron]]s are defined as [[strong interaction|strongly interacting]] '''composite particles'''<!--boldface per WP:R#PLA-->. Hadrons are either:
* [[Composite fermion]]s (especially 3 quarks), in which case they are called [[baryon]]s.
* [[Composite boson]]s (especially 2 quarks), in which case they are called [[meson]]s.

[[Quark model]]s, first proposed in 1964 independently by [[Murray Gell-Mann]] and [[George Zweig]] (who called quarks "aces"), describe the known hadrons as composed of valence [[quark]]s and/or antiquarks, tightly bound by the [[strong interaction|color force]], which is mediated by [[gluon]]s. (The interaction between quarks and gluons is described by the theory of [[quantum chromodynamics]].) A "sea" of virtual quark–antiquark pairs is also present in each hadron.

==== Baryons ====
[[File:Baryon decuplet.svg|thumb|A combination of three u, d or s-quarks with a total spin of {{sfrac|3|2}} form the so-called "baryon decuplet".]]
[[File:Quark_structure_proton.svg|thumb|Proton quark structure: 2 up quarks and 1 down quark.]]
{{main|List of baryons}}

Ordinary [[baryon]]s (composite [[fermion]]s) contain three valence quarks or three valence antiquarks each.
* [[Nucleon]]s are the fermionic constituents of normal atomic nuclei:
** [[Proton]]s, composed of two up and one down quark (uud)
** [[Neutron]]s, composed of two down and one up quark (ddu)
* [[Hyperon]]s, such as the Λ, Σ, Ξ, and Ω particles, which contain one or more [[strange quark]]s, are short-lived and heavier than nucleons. Although not normally present in atomic nuclei, they can appear in short-lived [[hypernucleus|hypernuclei]].
* A number of [[charm quark|charmed]] and [[bottom quark|bottom]] baryons have also been observed.
* [[Pentaquark]]s consist of four valence quarks and one valence antiquark.
* Other [[exotic baryon]]s may also exist.

==== Mesons ====
[[File:Noneto mesônico de spin 0.png|thumb|Mesons of spin 0 form a nonet.]]
{{main|List of mesons}}

Ordinary [[meson]]s are made up of a [[valence quark]] and a valence [[antiquark]]. Because mesons have integer [[Spin (physics)|spin]] (0 or 1) and are not themselves elementary particles, they are classified as "composite" [[bosons]], although being made of [[elementary particles|elementary]] [[fermions]]. Examples of mesons include the [[pion]], [[kaon]], and the [[J/ψ]]. In [[quantum hadrodynamics]], mesons mediate the [[residual strong force]] between nucleons.

At one time or another, positive [[signature]]s have been reported for all of the following [[exotic meson]]s but their existences have yet to be confirmed.
* A [[tetraquark]] consists of two valence quarks and two valence antiquarks;
* A [[glueball]] is a bound state of gluons with no valence quarks;
* [[Hybrid (particle physics)|Hybrid]] mesons consist of one or more valence quark–antiquark pairs and one or more real gluons.