particle physics Particle physics or high-energy physics is the study of Elementary particle, fundamental particles and fundamental interaction, forces that constitute matter and radiation. The field also studies combinations of elementary particles up to the s ...

, the term particle zoo is used

colloquially Colloquialism (also called ''colloquial language'', ''colloquial speech'', ''everyday language'', or ''general parlance'') is the linguistic style used for casual and informal communication. It is the most common form of speech in conversation am ...

to describe the relatively extensive list of known subatomic particles by analogy to the variety of species in a zoo. In the history of particle physics, the topic of particles was considered to be particularly confusing in the late 1960s. Before the discovery of quarks, hundreds of strongly interacting particles (

hadron In particle physics, a hadron is a composite subatomic particle made of two or more quarks held together by the strong nuclear force. Pronounced , the name is derived . They are analogous to molecules, which are held together by the electri ...

s) were known and believed to be distinct

elementary particle In particle physics, an elementary particle or fundamental particle is a subatomic particle that is not composed of other particles. The Standard Model presently recognizes seventeen distinct particles—twelve fermions and five bosons. As a c ...

s. It was later discovered that they were not elementary particles, but rather composites of

quark A quark () is a type of elementary particle and a fundamental constituent of matter. Quarks combine to form composite particles called hadrons, the most stable of which are protons and neutrons, the components of atomic nucleus, atomic nuclei ...

s. The set of particles believed today to be elementary is known as the

Standard Model The Standard Model of particle physics is the Scientific theory, theory describing three of the four known fundamental forces (electromagnetism, electromagnetic, weak interaction, weak and strong interactions – excluding gravity) in the unive ...

and includes

boson In particle physics, a boson ( ) is a subatomic particle whose spin quantum number has an integer value (0, 1, 2, ...). Bosons form one of the two fundamental classes of subatomic particle, the other being fermions, which have half odd-intege ...

s and leptons. The term " subnuclear zoo" was coined or popularized by Robert Oppenheimer in 1956 at the VI Rochester International Conference on High Energy Physics.George Johnson (1999). ''Strange Beauty: Murray Gell-Mann and the Revolution in Twentieth-Century Physics'', p. 755, footnote 108: Oppenheimer coined the term "subnuclear zoo" in a public lecture at the Rochester VI conference; Sec VIII, p 1 of the proceedings.

See also

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