Baryon

In particle physics, a baryon is a type of composite subatomic particle which contains an odd number of valence quarks (at least 3).[1] Baryons belong to the hadron family of particles, which are the quark-based particles. They are also classified as fermions, i.e., they have half-integer spin.

The name "baryon" comes from the Greek word for "heavy" (βαρύς, barýs), because, at the time of their naming, most known elementary particles had lower masses than the baryons. Each baryon has a corresponding antiparticle (antibaryon) where their corresponding antiquarks replace quarks. For example, a proton is made of two up quarks and one down quark; and its corresponding antiparticle, the antiproton, is made of two up antiquarks and one down antiquark.

As quark-based particles, baryons participate in the strong interaction, which is mediated by particles known as gluons. The most familiar baryons are protons and neutrons, both of which contain three quarks, and for this reason these particles are sometimes described as triquarks. These particles make up most of the mass of the visible matter in the universe, as well as forming the components of the nucleus of every atom. Electrons (the other major component of the atom) are members of a different family of particles, known as leptons, which do not interact via the strong force. Exotic baryons containing five quarks (known as pentaquarks) have also been discovered and studied.

Background

Baryons are strongly interacting fermions; that is, they are acted on by the strong nuclear force and are described by Fermi−Dirac statistics, which apply to all particles obeying the Pauli exclusion principle. This is in contrast to the bosons, which do not obey the exclusion principle.

Baryons, along with mesons, are hadrons, particles composed of quarks. Quarks have baryon numbers of B = 1/3 and antiquarks have baryon numbers of B = −1/3. The term "baryon" usually refers to triquarks—baryons made of three quarks (B = 1/3 + 1/3 + 1/3 = 1).

Other exotic baryons have been proposed, such as pentaquarks—baryons made of four quarks and one antiquark (B = 1/3 + 1/3 + 1/3 + 1/3 − 1/3 = 1),[2][3] but their existence is not generally accepted. The particle physics community as a whole did not view their existence as likely in 2006,[4] and in 2008, considered evidence to be overwhelmingly against the existence of the reported pentaquarks.[5] However, in July 2015, the LHCb experiment observed two resonances consistent with pentaquark states in the Λ0
b
→ J/ψK
p decay, with a combined statistical significance of 15σ.[6][7]

In theory, heptaquarks (5 quarks, 2 antiquarks), nonaquarks (6 quarks, 3 antiquarks), etc. could also exist.

Other Languages
Afrikaans: Barion
العربية: باريون
asturianu: Barión
беларуская: Барыён
български: Барион
bosanski: Barion
català: Barió
Чӑвашла: Барион
čeština: Baryon
Cymraeg: Baryon
Deutsch: Baryon
eesti: Barüonid
Ελληνικά: Βαρυόνιο
español: Barión
Esperanto: Bariono
euskara: Barioi
فارسی: باریون
français: Baryon
Gaeilge: Barón
한국어: 중입자
հայերեն: Բարիոն
hrvatski: Barion
Ido: Baryono
Bahasa Indonesia: Barion
íslenska: Þungeind
italiano: Barione
עברית: באריון
қазақша: Барион
kurdî: Baryon
Кыргызча: Барион заряды
Latina: Baryon
latviešu: Barioni
lietuvių: Barionas
Limburgs: Baryon
magyar: Barion
മലയാളം: ബേറിയോൺ
मराठी: बॅरिऑन
Bahasa Melayu: Barion
монгол: Барион
Nederlands: Baryon
日本語: バリオン
norsk: Baryon
norsk nynorsk: Baryon
oʻzbekcha/ўзбекча: Barionlar
پنجابی: بیریون
polski: Bariony
português: Bárion
română: Barion
русский: Барион
Scots: Baryon
Simple English: Baryon
slovenčina: Baryón
slovenščina: Barion
srpskohrvatski / српскохрватски: Barion
suomi: Baryoni
svenska: Baryon
தமிழ்: பேரியான்
татарча/tatarça: Barion
тоҷикӣ: Барион
Türkçe: Baryon
українська: Баріони
Tiếng Việt: Baryon
Winaray: Baryon
吴语: 重子
粵語: 重子
中文: 重子