Kuarks

Kuarks are a hypothetical class of fundamental fermions proposed in speculative physics theories and some science-fiction settings as an alternative to the quark of the Standard Model. In established physics, the term kuark is not used as a separate entity; the mainstream concept is the quark. When kuarks appear in discussions, they are typically part of a model that mirrors quark-like behavior or offers a variant to explore new dynamics.

Like quarks, kuarks are imagined as spin-1/2 particles that participate in the strong interaction and carry a form of color charge. They are assumed to come in six flavors, arranged in three generations, with electric charges that parallel those of quarks: up-type kuarks with +2/3e and down-type kuarks with −1/3e. They are also expected to obey quantum chromodynamics–like rules, including confinement, whereby individual kuarks cannot be isolated and are observed only within composite particles.

Kuarks would form hadrons through binding by the strong force. Three-kuark bound states would correspond to kuark baryons, while a kuark–antikuuark pair would form mesons in this framework. Masses would arise from a combination of intrinsic mass and binding energy, with weak and electromagnetic interactions described similarly to the quark model.

Etymology and usage vary: the term kuark is often employed in alternate-history, speculative, or fictional contexts as a stand-in for quark, or to explore how a different naming or charge assignment might alter particle phenomenology. In standard physics, no distinct empirical evidence supports kuarks as separate from quarks.