🕷️ Crawler Inspector

URL Lookup

Direct Parameter Lookup

Raw Queries and Responses

1. Shard Calculation

Query:

Response:

Calculated Shard: 124 (from laksa072)

2. Crawled Status Check

Query:

curl -X POST \
  'http://laksa124.int.ahrefs:8124/' \
  -H 'Content-Type: text/plain' \
  -H 'X-ClickHouse-Database: crawler3' \
  -H 'Authorization: Basic YXBpOg==' \
  -d 'SELECT getAhrefsURLFromUnparsed(src_unparsed) AS found_url, ifNull(toUnixTimestamp(download_stamp), 0) AS crawl_time, ifNull(toUnixTimestamp(props_url_first_seen), 0) AS first_indexed_time, download_http_code AS http_code, src_unparsed AS src_unparsed, src_root_hash AS src_root_hash, history_drop_reason AS history_drop_reason, meta_title AS meta_title, meta_descriptions AS meta_descriptions, attrs_boilerpipe_text AS attrs_boilerpipe_text, attrs_markdown AS attrs_markdown, attrs_readable_markdown AS attrs_readable_markdown, meta_canonical AS meta_canonical FROM crawler3.page_info_local FINAL PREWHERE (src_root_hash, src_unparsed) IN ((getAhrefsRootHashFromUnparsed(getAhrefsUnparsedNoserviceFromURL(\'https://www.newworldencyclopedia.org/entry/Baryon\')), getAhrefsUnparsedNoserviceFromURL(\'https://www.newworldencyclopedia.org/entry/Baryon\'))) FORMAT JSONEachRow'

Response:

{"found_url":"https:\/\/www.newworldencyclopedia.org\/entry\/Baryon","crawl_time":1776484427,"first_indexed_time":1376193846,"http_code":200,"src_unparsed":"org,newworldencyclopedia!www,\/entry\/Baryon s443","src_root_hash":"5774774004535495924","history_drop_reason":null,"meta_title":"Baryon - New World Encyclopedia","meta_descriptions":[],"attrs_boilerpipe_text":"A\nproton\nis an example of a baryon. It is composed of 2 up quarks (u) and 1 down quark (d).\nThe term\nbaryon\nusually refers to a\nsubatomic particle\ncomposed of three\nquarks\n.\n[1]\nA more technical (and broader) definition is that it is a subatomic particle with a baryon number of 1. Baryons are a subset of\nhadrons\n, (which are particles made of quarks), and they participate in the strong interaction. They are also a subset of\nfermions\n. Well-known examples of baryons are\nprotons\nand\nneutrons\n, which make up\natomic nuclei\n, but many unstable baryons have been found as well.\nSome \"exotic\" baryons, known as pentaquarks, are thought to be composed of four quarks and one antiquark, but their existence is not generally accepted. Each baryon has a corresponding antiparticle, called an\nanti-baryon,\nin which quarks are replaced by their corresponding antiquarks.\nEtymology\nThe term\nbaryon\nis derived from the\nGreek\nword\nβαρύς\n(barys)\n, meaning \"heavy,\" because at the time of their naming it was believed that baryons were characterized by having greater mass than other particles.\nBasic properties\nEach baryon has an odd half-integer spin (such as\n1\n⁄\n2\nor\n3\n⁄\n2\n), where \"spin\" refers to the angular momentum quantum number. Baryons are therefore classified as\nfermions\n. They experience the strong nuclear force and are described by Fermi-Dirac statistics, which apply to all particles obeying the Pauli exclusion principle. This stands in contrast to\nbosons\n, which do not obey the exclusion principle.\nBaryons, along with\nmesons\n, are\nhadrons\n, meaning they are particles composed of\nquarks\n. Each quark has a baryon number of B = \n1\n⁄\n3\n, and each antiquark has a baryon number of B = −\n1\n⁄\n3\n.\nThe term\nbaryon number\nis defined as:\nwhere\nis the number of quarks, and\nis the number of antiquarks.\nThe term \"baryon\" is usually used for\ntriquarks,\nthat is, baryons made of three quarks. Thus, each baryon has a baryon number of 1 (B = \n1\n⁄\n3\n + \n1\n⁄\n3\n + \n1\n⁄\n3\n = 1).\nSome have suggested the existence of other, \"exotic\" baryons, such as pentaquarks—baryons made of four quarks and one antiquark (B = \n1\n⁄\n3\n + \n1\n⁄\n3\n + \n1\n⁄\n3\n + \n1\n⁄\n3\n − \n1\n⁄\n3\n = 1)—but their existence is not generally accepted. Theoretically, heptaquarks (5 quarks, 2 antiquarks), nonaquarks (6 quarks, 3 antiquarks), and so forth could also exist.\nBesides being associated with a spin number and a baryon number, each baryon has a quantum number known as\nstrangeness\n. This quantity is equal to -1 times the number of strange quarks present in the baryon.\n[2]\nClassification\nCombinations of three u, d or s-quarks with a total spin of 3\/2 form the so-called\nbaryon decuplet.\nThe\noctet\nof light spin-1\/2 baryons.\nBaryons are classified into groups according to their isospin values and\nquark\ncontent. There are six groups of triquarks:\nNucleon (\nN\n)\nDelta (\nΔ\n)\nLambda (\nΛ\n)\nSigma (\nΣ\n)\nXi (\nΞ\n)\nOmega (\nΩ\n)\nThe rules for classification are defined by the Particle Data Group. The rules cover all the particles that can be made from three of each of the six quarks (up, down, strange, charm, bottom, top), although baryons made of top quarks are not expected to exist because of the top quark's short lifetime. (The rules do not cover pentaquarks.)\n[3]\nAccording to these rules, the\nu\n,\nd\n, and\ns\nquarks are considered\nlight,\nand the\nc\n,\nb\n, and\nt\nquarks are considered\nheavy\n.\nBased on the rules, the following classification system has been set up:\nBaryons with three\nu\nand\/or\nd\nquarks are grouped as\nN\n(isospin\n1\n⁄\n2\n) or\nΔ\n(isospin\n3\n⁄\n2\n).\nBaryons with two\nu\nand\/or\nd\nquarks are grouped as\nΛ\n(isospin 0) or\nΣ\n(isospin 1). If the third quark is heavy, its identity is given by a subscript.\nBaryons with one\nu\nor\nd\nquark are placed in the group\nΞ\n(isospin\n1\n⁄\n2\n). One or two subscripts are used if one or both of the remaining quarks are heavy.\nBaryons with no\nu\nor\nd\nquarks are placed in the group\nΩ\n(isospin 0), and subscripts indicate any heavy quark content.\nSome baryons decay strongly, in which case their masses are shown as part of their names. For example, Sigmas (\nΣ\n) and Omegas (\nΩ\n) do not decay strongly, but Deltas (\nΔ\n(1232)\n), and charmed Xis (\nΞ\n+\nc\n(2645)\n) do.\nGiven that quarks carry charge, knowledge of the charge of a particle indirectly gives the quark content. For example, the rules say that the\nΣ\nb\ncontains a bottom and some combination of two up and\/or down quarks. A\nΣ\n0\nb\nmust be one up quark (Q=\n2\n⁄\n3\n), one down quark (Q=−\n1\n⁄\n3\n), and one bottom quark (Q=−\n1\n⁄\n3\n) to have the correct charge (Q=0).\nThe number of baryons within one group (excluding resonances) is given by the number of isospin projections possible (2 × isospin + 1). For example, there are four\nΔ\n's, corresponding to the four isospin projections of the isospin value I = \n3\n⁄\n2\n:\nΔ\n++\n(I\nz\n = \n3\n⁄\n2\n),\nΔ\n+\n(I\nz\n = \n1\n⁄\n2\n),\nΔ\n0\n(I\nz\n = −\n1\n⁄\n2\n), and\nΔ\n−\n(I\nz\n = −\n3\n⁄\n2\n). Another example would be the three\nΣ\nb\n's, corresponding to the three isospin projections of the isospin value I = 1:\nΣ\n+\nb\n(I\nz\n = 1),\nΣ\n0\nb\n(I\nz\n = 0), and\nΣ\n−\nb\n(I\nz\n = −1).\nCharmed baryons\nBaryons that are composed of at least one charm quark are known as\ncharmed baryons\n.\nBaryonic matter\nBaryonic\nmatter\nis matter composed mostly of baryons (by mass). It includes\natoms\nof all types, and thus includes nearly all types of matter that we may encounter or experience in everyday life, including the matter that constitutes human bodies.\nNon-baryonic matter,\nas implied by the name, is any sort of matter that is not primarily composed of baryons. It may include such ordinary matter as neutrinos or free\nelectrons\n, but it may also include exotic species of non-baryonic\ndark matter\n, such as supersymmetric particles, axions, or black holes.\nThe distinction between baryonic and non-baryonic matter is important in cosmology, because Big Bang nucleosynthesis models set tight constraints on the amount of baryonic matter present in the early\nuniverse\n.\nThe very existence of baryons is also a significant issue in cosmology because current theory assumes that the Big Bang produced a state with equal amounts of baryons and anti-baryons. The process by which baryons came to outnumber their antiparticles is called\nbaryogenesis\n. (This is distinct from a process by which\nleptons\naccount for the predominance of matter over antimatter, known as\nleptogenesis\n.)\nBaryogenesis\nExperiments are consistent with the number of quarks in the universe being a constant and, more specifically, the number of\nbaryons\nbeing a constant; in technical language, the total baryon number appears to be\nconserved.\nWithin the prevailing\nStandard Model\nof particle physics, the number of baryons may change in multiples of three due to the action of sphalerons, although this is rare and has not been observed experimentally. Some grand unified theories of particle physics also predict that a single\nproton\ncan decay, changing the baryon number by one; however, this has not yet been observed experimentally. The excess of baryons over antibaryons in the present universe is thought to be due to non-conservation of baryon number in the very early universe, though this is not well understood.\nSee also\nAntimatter\nAtom\nDark matter\nFermion\nHadron\nLepton\nMatter\nMeson\nNeutron\nParticle physics\nProton\nQuark\nStandard Model\nSubatomic particle\nNotes\n↑\nThe Particle Adventure,\nHadrons: Baryons and Mesons.\nRetrieved September 10, 2008.\n↑\nHyper Physics,\nBaryons.\nRetrieved September 10, 2008.\n↑\nM. Roos and C.G. Wohl,\nNaming Scheme for Hadrons,\nJ. Phys\nG 33:1. Retrieved September 10, 2008.\nReferences\nISBN links support NWE through referral fees\nCottingham, W.N., and D.A. Greenwood.\nAn Introduction to the Standard Model of Particle Physics,\n2nd edition. Cambridge: Cambridge University Press, 2007.\nISBN 978-0521852494\nGriffiths, David J.\nIntroduction to Elementary Particles\n. New York: Wiley, 1987.\nISBN 0471603864\nHalzen, Francis, and Alan D. Martin.\nQuarks and Leptons: An Introductory Course in Modern Particle Physics\n. New York: Wiley, 1984.\nISBN 0471887412\nMartin, B. R.\nNuclear and Particle Physics: An Introduction\n. Chichester: John Wiley, 2006.\nISBN 978-0470025321\nPovh, Bogdan.\nParticles and Nuclei: An Introduction to the Physical Concepts\n. Berlin: Springer-Verlag, 1995.\nISBN 0387594396\nVeltman, Martinus.\nFacts and Mysteries in Elementary Particle Physics.\nRiver Edge, NJ: World Scientific, 2003.\nISBN 981238149X\nExternal links\nAll links retrieved September 20, 2023.\nBaryons\n.\nTable of Baryons\n.\nThe Review of Particle Physics\n. Particle Data Group.\nParticles in physics\nelementary particles\nElementary\nfermions\n:\n \nQuarks\n: u · d · s · c · b · t •\nLeptons\n:\ne\n·  μ · τ  ·\nν\ne\n· ν\nμ\n· ν\nτ\nElementary\nbosons\n:\n \nGauge bosons\n:\nγ\n· g ·\nW\n±\n· Z\n0\n•\nGhosts\nComposite particles\nHadrons\n:\n \nBaryons\n(list)\/\nHyperons\n\/\nNucleons\n:\np\n·\nn\n· Δ · Λ · Σ · Ξ · Ω ·\nΞ\nb\n•\nMesons\n(list)\/\nQuarkonia\n: π · K · ρ · J\/ψ · Υ\nOther:\n \nAtomic nucleus\n•\nAtoms\n•\nMolecules\n•\nPositronium\nHypothetical elementary particles\nSuperpartners:\nAxino · Dilatino · Chargino · Gluino · Gravitino · Higgsino · Neutralino · Sfermion · Slepton · Squark\nOther:\nAxion · Dilaton · Goldstone boson · Graviton · Higgs boson · Tachyon · X · Y · W' · Z'\nHypothetical composite particles\nExotic hadrons:\n \nExotic baryons\n: Pentaquark •\nExotic mesons\n: Glueball · Tetraquark\nOther:\n \nMesonic molecule\nQuasiparticles\nDavydov soliton · Exciton · Magnon · Phonon · Plasmon · Polariton · Polaron\nCredits\nNew World Encyclopedia\nwriters and editors rewrote and completed the\nWikipedia\narticle \nin accordance with\nNew World Encyclopedia\nstandards\n. This article abides by terms of the\nCreative Commons CC-by-sa 3.0 License\n(CC-by-sa), which may be used and disseminated with proper attribution. Credit is due under the terms of this license that can reference both the\nNew World Encyclopedia\ncontributors and the selfless volunteer contributors of the Wikimedia Foundation. To cite this article\nclick here\nfor a list of acceptable citing formats.The history of earlier contributions by wikipedians is accessible to researchers here:\nBaryon\n \nhistory\nBaryon_number\n \nhistory\nCharmed_baryon\n \nhistory\nThe history of this article since it was imported to\nNew World Encyclopedia\n:\nHistory of \"Baryon\"\nNote: Some restrictions may apply to use of individual images which are separately licensed.","attrs_markdown":"[![Research Begins Here](https:\/\/www.newworldencyclopedia.org\/images\/nwe_header.jpg)](https:\/\/www.newworldencyclopedia.org\/ \"Visit the main page\")\n\n[Articles](https:\/\/www.newworldencyclopedia.org\/entry\/Category:Copyedited)\n\n[About](https:\/\/www.newworldencyclopedia.org\/entry\/Info:Project_Vision)\n\n[Feedback](https:\/\/www.newworldencyclopedia.org\/feedback\/baryon)\n\n# Baryon\nFrom New World Encyclopedia\n\nJump to:[navigation](https:\/\/www.newworldencyclopedia.org\/entry\/Baryon#mw-navigation), [search](https:\/\/www.newworldencyclopedia.org\/entry\/Baryon#p-search)\n\n[Previous (Baruch Spinoza)](https:\/\/www.newworldencyclopedia.org\/entry\/Baruch_Spinoza \"Baruch Spinoza\")\n\n[Next (Basalt)](https:\/\/www.newworldencyclopedia.org\/entry\/Basalt \"Basalt\")\n\n[![](https:\/\/www.newworldencyclopedia.org\/d\/images\/thumb\/9\/92\/Quark_structure_proton.svg\/200px-Quark_structure_proton.svg.png)](https:\/\/www.newworldencyclopedia.org\/entry\/File:Quark_structure_proton.svg)\n\nA [proton](https:\/\/www.newworldencyclopedia.org\/entry\/Proton \"Proton\") is an example of a baryon. It is composed of 2 up quarks (u) and 1 down quark (d).\n\nThe term **baryon** usually refers to a [subatomic particle](https:\/\/www.newworldencyclopedia.org\/entry\/Subatomic_particle \"Subatomic particle\") composed of three [quarks](https:\/\/www.newworldencyclopedia.org\/entry\/Quark \"Quark\").[\\[1\\]](https:\/\/www.newworldencyclopedia.org\/entry\/Baryon#cite_note-1) A more technical (and broader) definition is that it is a subatomic particle with a baryon number of 1. Baryons are a subset of [hadrons](https:\/\/www.newworldencyclopedia.org\/entry\/Hadron \"Hadron\"), (which are particles made of quarks), and they participate in the strong interaction. They are also a subset of [fermions](https:\/\/www.newworldencyclopedia.org\/entry\/Fermion \"Fermion\"). Well-known examples of baryons are [protons](https:\/\/www.newworldencyclopedia.org\/entry\/Proton \"Proton\") and [neutrons](https:\/\/www.newworldencyclopedia.org\/entry\/Neutron \"Neutron\"), which make up [atomic nuclei](https:\/\/www.newworldencyclopedia.org\/entry\/Atomic_nucleus \"Atomic nucleus\"), but many unstable baryons have been found as well.\n\n## Contents\n- [1 Etymology](https:\/\/www.newworldencyclopedia.org\/entry\/Baryon#Etymology)\n- [2 Basic properties](https:\/\/www.newworldencyclopedia.org\/entry\/Baryon#Basic_properties)\n- [3 Classification](https:\/\/www.newworldencyclopedia.org\/entry\/Baryon#Classification)\n  - [3\\.1 Charmed baryons](https:\/\/www.newworldencyclopedia.org\/entry\/Baryon#Charmed_baryons)\n- [4 Baryonic matter](https:\/\/www.newworldencyclopedia.org\/entry\/Baryon#Baryonic_matter)\n- [5 Baryogenesis](https:\/\/www.newworldencyclopedia.org\/entry\/Baryon#Baryogenesis)\n- [6 See also](https:\/\/www.newworldencyclopedia.org\/entry\/Baryon#See_also)\n- [7 Notes](https:\/\/www.newworldencyclopedia.org\/entry\/Baryon#Notes)\n- [8 References](https:\/\/www.newworldencyclopedia.org\/entry\/Baryon#References)\n- [9 External links](https:\/\/www.newworldencyclopedia.org\/entry\/Baryon#External_links)\n- [10 Credits](https:\/\/www.newworldencyclopedia.org\/entry\/Baryon#Credits)\n\nSome \"exotic\" baryons, known as pentaquarks, are thought to be composed of four quarks and one antiquark, but their existence is not generally accepted. Each baryon has a corresponding antiparticle, called an **anti-baryon,** in which quarks are replaced by their corresponding antiquarks.\n\n## Etymology\nThe term *baryon* is derived from the [Greek](https:\/\/www.newworldencyclopedia.org\/entry\/Greek_language \"Greek language\") word *βαρύς* *(barys)*, meaning \"heavy,\" because at the time of their naming it was believed that baryons were characterized by having greater mass than other particles.\n\n## Basic properties\nEach baryon has an odd half-integer spin (such as 1 ⁄ 2 or 3 ⁄ 2), where \"spin\" refers to the angular momentum quantum number. Baryons are therefore classified as *[fermions](https:\/\/www.newworldencyclopedia.org\/entry\/Fermion \"Fermion\")*. They experience the strong nuclear force and are described by Fermi-Dirac statistics, which apply to all particles obeying the Pauli exclusion principle. This stands in contrast to [bosons](https:\/\/www.newworldencyclopedia.org\/entry\/Boson \"Boson\"), which do not obey the exclusion principle.\n\nBaryons, along with [mesons](https:\/\/www.newworldencyclopedia.org\/entry\/Meson \"Meson\"), are [hadrons](https:\/\/www.newworldencyclopedia.org\/entry\/Hadron \"Hadron\"), meaning they are particles composed of [quarks](https:\/\/www.newworldencyclopedia.org\/entry\/Quark \"Quark\"). Each quark has a baryon number of B = 1 ⁄ 3, and each antiquark has a baryon number of B = −1 ⁄ 3.\n\nThe term *baryon number* is defined as:\n\nB\n\n\\=\n\nN\n\nq\n\n−\n\nN\n\nq\n\n¯\n\n3\n\n{\\\\displaystyle B={\\\\frac {N\\_{q}-N\\_{\\\\overline {q}}}{3}}}\n\n![{\\\\displaystyle B={\\\\frac {N\\_{q}-N\\_{\\\\overline {q}}}{3}}}](https:\/\/wikimedia.org\/api\/rest_v1\/media\/math\/render\/svg\/4353f4b7742621261045bfed6830d88ce839358b)\n\nwhere\n\nN\n\nq\n\n{\\\\displaystyle N\\_{q}\\\\ }\n\n![{\\\\displaystyle N\\_{q}\\\\ }](https:\/\/wikimedia.org\/api\/rest_v1\/media\/math\/render\/svg\/deedebab19fde96882032b92aeb46a667d963598)\n\nis the number of quarks, and\n\nN\n\nq\n\n¯\n\n{\\\\displaystyle N\\_{\\\\overline {q}}}\n\n![{\\\\displaystyle N\\_{\\\\overline {q}}}](https:\/\/wikimedia.org\/api\/rest_v1\/media\/math\/render\/svg\/6f4711277ecf2dba9a848fbb60a4f02b30b55641)\n\nis the number of antiquarks.\n\nThe term \"baryon\" is usually used for *triquarks,* that is, baryons made of three quarks. Thus, each baryon has a baryon number of 1 (B = 1 ⁄ 3 + 1 ⁄ 3 + 1 ⁄ 3 = 1).\n\nSome have suggested the existence of other, \"exotic\" baryons, such as pentaquarks—baryons made of four quarks and one antiquark (B = 1 ⁄ 3 + 1 ⁄ 3 + 1 ⁄ 3 + 1 ⁄ 3 − 1 ⁄ 3 = 1)—but their existence is not generally accepted. Theoretically, heptaquarks (5 quarks, 2 antiquarks), nonaquarks (6 quarks, 3 antiquarks), and so forth could also exist.\n\nBesides being associated with a spin number and a baryon number, each baryon has a quantum number known as *strangeness*. This quantity is equal to -1 times the number of strange quarks present in the baryon.[\\[2\\]](https:\/\/www.newworldencyclopedia.org\/entry\/Baryon#cite_note-2)\n\n## Classification\n[![](https:\/\/www.newworldencyclopedia.org\/d\/images\/thumb\/f\/f6\/Baryon_decuplet.svg\/200px-Baryon_decuplet.svg.png)](https:\/\/www.newworldencyclopedia.org\/entry\/File:Baryon_decuplet.svg)\n\nCombinations of three u, d or s-quarks with a total spin of 3\/2 form the so-called **baryon decuplet.**\n\n[![](https:\/\/www.newworldencyclopedia.org\/d\/images\/thumb\/f\/f6\/Baryon_octet.svg\/200px-Baryon_octet.svg.png)](https:\/\/www.newworldencyclopedia.org\/entry\/File:Baryon_octet.svg)\n\nThe **octet** of light spin-1\/2 baryons.\n\nBaryons are classified into groups according to their isospin values and [quark](https:\/\/www.newworldencyclopedia.org\/entry\/Quark \"Quark\") content. There are six groups of triquarks:\n\n- Nucleon (N)\n- Delta (Δ)\n- Lambda (Λ)\n- Sigma (Σ)\n- Xi (Ξ)\n- Omega (Ω)\n\nThe rules for classification are defined by the Particle Data Group. The rules cover all the particles that can be made from three of each of the six quarks (up, down, strange, charm, bottom, top), although baryons made of top quarks are not expected to exist because of the top quark's short lifetime. (The rules do not cover pentaquarks.)[\\[3\\]](https:\/\/www.newworldencyclopedia.org\/entry\/Baryon#cite_note-PDGBaryonsymbols-3) According to these rules, the [u](https:\/\/www.newworldencyclopedia.org\/p\/index.php?title=Up_quark&action=edit&redlink=1 \"Up quark (page does not exist)\"), [d](https:\/\/www.newworldencyclopedia.org\/p\/index.php?title=Down_quark&action=edit&redlink=1 \"Down quark (page does not exist)\"), and [s](https:\/\/www.newworldencyclopedia.org\/p\/index.php?title=Strange_quark&action=edit&redlink=1 \"Strange quark (page does not exist)\") quarks are considered *light,* and the [c](https:\/\/www.newworldencyclopedia.org\/p\/index.php?title=Charm_quark&action=edit&redlink=1 \"Charm quark (page does not exist)\"), [b](https:\/\/www.newworldencyclopedia.org\/p\/index.php?title=Bottom_quark&action=edit&redlink=1 \"Bottom quark (page does not exist)\"), and [t](https:\/\/www.newworldencyclopedia.org\/p\/index.php?title=Top_quark&action=edit&redlink=1 \"Top quark (page does not exist)\") quarks are considered *heavy*.\n\nBased on the rules, the following classification system has been set up:\n\n- Baryons with three [u](https:\/\/www.newworldencyclopedia.org\/p\/index.php?title=Up_quark&action=edit&redlink=1 \"Up quark (page does not exist)\") and\/or [d](https:\/\/www.newworldencyclopedia.org\/p\/index.php?title=Down_quark&action=edit&redlink=1 \"Down quark (page does not exist)\") quarks are grouped as [N](https:\/\/www.newworldencyclopedia.org\/p\/index.php?title=Nucleon&action=edit&redlink=1 \"Nucleon (page does not exist)\") (isospin\n  1\n  \n  ⁄\n  \n  2\n  ) or [Δ](https:\/\/www.newworldencyclopedia.org\/p\/index.php?title=Delta_baryon&action=edit&redlink=1 \"Delta baryon (page does not exist)\") (isospin\n  3\n  \n  ⁄\n  \n  2\n  ).\n- Baryons with two [u](https:\/\/www.newworldencyclopedia.org\/p\/index.php?title=Up_quark&action=edit&redlink=1 \"Up quark (page does not exist)\") and\/or [d](https:\/\/www.newworldencyclopedia.org\/p\/index.php?title=Down_quark&action=edit&redlink=1 \"Down quark (page does not exist)\") quarks are grouped as [Λ](https:\/\/www.newworldencyclopedia.org\/p\/index.php?title=Lambda_baryon&action=edit&redlink=1 \"Lambda baryon (page does not exist)\") (isospin 0) or [Σ](https:\/\/www.newworldencyclopedia.org\/p\/index.php?title=Sigma_baryon&action=edit&redlink=1 \"Sigma baryon (page does not exist)\") (isospin 1). If the third quark is heavy, its identity is given by a subscript.\n- Baryons with one [u](https:\/\/www.newworldencyclopedia.org\/p\/index.php?title=Up_quark&action=edit&redlink=1 \"Up quark (page does not exist)\") or [d](https:\/\/www.newworldencyclopedia.org\/p\/index.php?title=Down_quark&action=edit&redlink=1 \"Down quark (page does not exist)\") quark are placed in the group [Ξ](https:\/\/www.newworldencyclopedia.org\/p\/index.php?title=Xi_baryon&action=edit&redlink=1 \"Xi baryon (page does not exist)\") (isospin\n  1\n  \n  ⁄\n  \n  2\n  ). One or two subscripts are used if one or both of the remaining quarks are heavy.\n- Baryons with no [u](https:\/\/www.newworldencyclopedia.org\/p\/index.php?title=Up_quark&action=edit&redlink=1 \"Up quark (page does not exist)\") or [d](https:\/\/www.newworldencyclopedia.org\/p\/index.php?title=Down_quark&action=edit&redlink=1 \"Down quark (page does not exist)\") quarks are placed in the group [Ω](https:\/\/www.newworldencyclopedia.org\/p\/index.php?title=Omega_baryon&action=edit&redlink=1 \"Omega baryon (page does not exist)\") (isospin 0), and subscripts indicate any heavy quark content.\n- Some baryons decay strongly, in which case their masses are shown as part of their names. For example, Sigmas (Σ) and Omegas (Ω) do not decay strongly, but Deltas (Δ(1232)), and charmed Xis (Ξ\\+c(2645)) do.\n\nGiven that quarks carry charge, knowledge of the charge of a particle indirectly gives the quark content. For example, the rules say that the Σb contains a bottom and some combination of two up and\/or down quarks. A Σ0b must be one up quark (Q=2 ⁄ 3), one down quark (Q=−1 ⁄ 3), and one bottom quark (Q=−1 ⁄ 3) to have the correct charge (Q=0).\n\nThe number of baryons within one group (excluding resonances) is given by the number of isospin projections possible (2 × isospin + 1). For example, there are four Δ's, corresponding to the four isospin projections of the isospin value I = 3 ⁄ 2: Δ\\++ (Iz = 3 ⁄ 2), Δ\\+(Iz = 1 ⁄ 2), Δ0(Iz = −1 ⁄ 2), and Δ−(Iz = −3 ⁄ 2). Another example would be the three Σb's, corresponding to the three isospin projections of the isospin value I = 1: Σ\\+b (Iz = 1), Σ0b(Iz = 0), and Σ−b(Iz = −1).\n\n### Charmed baryons\nBaryons that are composed of at least one charm quark are known as *charmed baryons*.\n\n## Baryonic matter\n**Baryonic [matter](https:\/\/www.newworldencyclopedia.org\/entry\/Matter \"Matter\")** is matter composed mostly of baryons (by mass). It includes [atoms](https:\/\/www.newworldencyclopedia.org\/entry\/Atom \"Atom\") of all types, and thus includes nearly all types of matter that we may encounter or experience in everyday life, including the matter that constitutes human bodies. **Non-baryonic matter,** as implied by the name, is any sort of matter that is not primarily composed of baryons. It may include such ordinary matter as neutrinos or free [electrons](https:\/\/www.newworldencyclopedia.org\/entry\/Electron \"Electron\"), but it may also include exotic species of non-baryonic [dark matter](https:\/\/www.newworldencyclopedia.org\/entry\/Dark_matter \"Dark matter\"), such as supersymmetric particles, axions, or black holes.\n\nThe distinction between baryonic and non-baryonic matter is important in cosmology, because Big Bang nucleosynthesis models set tight constraints on the amount of baryonic matter present in the early [universe](https:\/\/www.newworldencyclopedia.org\/entry\/Universe \"Universe\").\n\nThe very existence of baryons is also a significant issue in cosmology because current theory assumes that the Big Bang produced a state with equal amounts of baryons and anti-baryons. The process by which baryons came to outnumber their antiparticles is called *baryogenesis*. (This is distinct from a process by which [leptons](https:\/\/www.newworldencyclopedia.org\/entry\/Lepton \"Lepton\") account for the predominance of matter over antimatter, known as *leptogenesis*.)\n\n## Baryogenesis\nExperiments are consistent with the number of quarks in the universe being a constant and, more specifically, the number of [baryons]() being a constant; in technical language, the total baryon number appears to be *conserved.* Within the prevailing [Standard Model](https:\/\/www.newworldencyclopedia.org\/entry\/Standard_Model \"Standard Model\") of particle physics, the number of baryons may change in multiples of three due to the action of sphalerons, although this is rare and has not been observed experimentally. Some grand unified theories of particle physics also predict that a single [proton](https:\/\/www.newworldencyclopedia.org\/entry\/Proton \"Proton\") can decay, changing the baryon number by one; however, this has not yet been observed experimentally. The excess of baryons over antibaryons in the present universe is thought to be due to non-conservation of baryon number in the very early universe, though this is not well understood.\n\n## See also\n- [Antimatter](https:\/\/www.newworldencyclopedia.org\/entry\/Antimatter \"Antimatter\")\n- [Atom](https:\/\/www.newworldencyclopedia.org\/entry\/Atom \"Atom\")\n- [Dark matter](https:\/\/www.newworldencyclopedia.org\/entry\/Dark_matter \"Dark matter\")\n- [Fermion](https:\/\/www.newworldencyclopedia.org\/entry\/Fermion \"Fermion\")\n- [Hadron](https:\/\/www.newworldencyclopedia.org\/entry\/Hadron \"Hadron\")\n- [Lepton](https:\/\/www.newworldencyclopedia.org\/entry\/Lepton \"Lepton\")\n- [Matter](https:\/\/www.newworldencyclopedia.org\/entry\/Matter \"Matter\")\n- [Meson](https:\/\/www.newworldencyclopedia.org\/entry\/Meson \"Meson\")\n- [Neutron](https:\/\/www.newworldencyclopedia.org\/entry\/Neutron \"Neutron\")\n- [Particle physics](https:\/\/www.newworldencyclopedia.org\/entry\/Particle_physics \"Particle physics\")\n- [Proton](https:\/\/www.newworldencyclopedia.org\/entry\/Proton \"Proton\")\n- [Quark](https:\/\/www.newworldencyclopedia.org\/entry\/Quark \"Quark\")\n- [Standard Model](https:\/\/www.newworldencyclopedia.org\/entry\/Standard_Model \"Standard Model\")\n- [Subatomic particle](https:\/\/www.newworldencyclopedia.org\/entry\/Subatomic_particle \"Subatomic particle\")\n## Notes\n1. [↑](https:\/\/www.newworldencyclopedia.org\/entry\/Baryon#cite_ref-1) The Particle Adventure, [Hadrons: Baryons and Mesons.](http:\/\/www.particleadventure.org\/frameless\/hadrons.html) Retrieved September 10, 2008.\n2. [↑](https:\/\/www.newworldencyclopedia.org\/entry\/Baryon#cite_ref-2) Hyper Physics, [Baryons.](http:\/\/hyperphysics.phy-astr.gsu.edu\/Hbase\/particles\/hadron.html) Retrieved September 10, 2008.\n3. [↑](https:\/\/www.newworldencyclopedia.org\/entry\/Baryon#cite_ref-PDGBaryonsymbols_3-0) M. Roos and C.G. Wohl, [Naming Scheme for Hadrons,](http:\/\/pdg.lbl.gov\/2007\/reviews\/namingrpp.pdf) *J. Phys* G 33:1. Retrieved September 10, 2008.\n## ReferencesISBN links support NWE through referral fees\n- Cottingham, W.N., and D.A. Greenwood. *An Introduction to the Standard Model of Particle Physics,* 2nd edition. Cambridge: Cambridge University Press, 2007. [ISBN 978-0521852494](https:\/\/www.amazon.com\/gp\/product\/0521852498\/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0521852498&linkCode=as2&tag=newworldencyc-20&linkId=83df4bed72539f2a52beb06a1d71be79)\n- Griffiths, David J. *Introduction to Elementary Particles*. New York: Wiley, 1987. [ISBN 0471603864](https:\/\/www.amazon.com\/gp\/product\/0471603864\/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0471603864&linkCode=as2&tag=newworldencyc-20&linkId=83df4bed72539f2a52beb06a1d71be79)\n- Halzen, Francis, and Alan D. Martin. *Quarks and Leptons: An Introductory Course in Modern Particle Physics*. New York: Wiley, 1984. [ISBN 0471887412](https:\/\/www.amazon.com\/gp\/product\/0471887412\/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0471887412&linkCode=as2&tag=newworldencyc-20&linkId=83df4bed72539f2a52beb06a1d71be79)\n- Martin, B. R. *Nuclear and Particle Physics: An Introduction*. Chichester: John Wiley, 2006. [ISBN 978-0470025321](https:\/\/www.amazon.com\/gp\/product\/0470025328\/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0470025328&linkCode=as2&tag=newworldencyc-20&linkId=83df4bed72539f2a52beb06a1d71be79)\n- Povh, Bogdan. *Particles and Nuclei: An Introduction to the Physical Concepts*. Berlin: Springer-Verlag, 1995. [ISBN 0387594396](https:\/\/www.amazon.com\/gp\/product\/0387594396\/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0387594396&linkCode=as2&tag=newworldencyc-20&linkId=83df4bed72539f2a52beb06a1d71be79)\n- Veltman, Martinus. *Facts and Mysteries in Elementary Particle Physics.* River Edge, NJ: World Scientific, 2003. [ISBN 981238149X](https:\/\/www.amazon.com\/gp\/product\/981238149X\/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=981238149X&linkCode=as2&tag=newworldencyc-20&linkId=83df4bed72539f2a52beb06a1d71be79)\n## External links\nAll links retrieved September 20, 2023.\n\n- [Baryons](http:\/\/hyperphysics.phy-astr.gsu.edu\/Hbase\/particles\/hadron.html).\n- [Table of Baryons](http:\/\/hyperphysics.phy-astr.gsu.edu\/hbase\/particles\/baryon.html#c1).\n- [The Review of Particle Physics](http:\/\/pdg.lbl.gov\/). Particle Data Group.\n***\n| Particles in physics |   |\n|---|---|\n| [elementary particles](https:\/\/www.newworldencyclopedia.org\/entry\/Elementary_particle \"Elementary particle\") | **Elementary [fermions](https:\/\/www.newworldencyclopedia.org\/entry\/Fermion \"Fermion\"):** **[Quarks](https:\/\/www.newworldencyclopedia.org\/entry\/Quark \"Quark\")**: u · d · s · c · b · t • **[Leptons](https:\/\/www.newworldencyclopedia.org\/entry\/Lepton \"Lepton\")**: [e](https:\/\/www.newworldencyclopedia.org\/entry\/Electron \"Electron\") · μ · τ · [νe · νμ · ντ](https:\/\/www.newworldencyclopedia.org\/p\/index.php?title=Neutrino&action=edit&redlink=1 \"Neutrino (page does not exist)\")  **Elementary [bosons](https:\/\/www.newworldencyclopedia.org\/entry\/Boson \"Boson\"):** **Gauge bosons**: [γ](https:\/\/www.newworldencyclopedia.org\/entry\/Photon \"Photon\") · g · [W± · Z0](https:\/\/www.newworldencyclopedia.org\/p\/index.php?title=W_and_Z_bosons&action=edit&redlink=1 \"W and Z bosons (page does not exist)\") • **Ghosts** |\n| Composite particles | **[Hadrons](https:\/\/www.newworldencyclopedia.org\/entry\/Hadron \"Hadron\"):** **[Baryons]()**(list)\/**Hyperons**\/**Nucleons**: [p](https:\/\/www.newworldencyclopedia.org\/entry\/Proton \"Proton\") · [n](https:\/\/www.newworldencyclopedia.org\/entry\/Neutron \"Neutron\") · Δ · Λ · Σ · Ξ · Ω · [Ξb](https:\/\/www.newworldencyclopedia.org\/p\/index.php?title=Cascade_B&action=edit&redlink=1 \"Cascade B (page does not exist)\") • **[Mesons](https:\/\/www.newworldencyclopedia.org\/entry\/Meson \"Meson\")**(list)\/**Quarkonia**: π · K · ρ · J\/ψ · Υ  **Other:** **[Atomic nucleus](https:\/\/www.newworldencyclopedia.org\/entry\/Atomic_nucleus \"Atomic nucleus\")** • **[Atoms](https:\/\/www.newworldencyclopedia.org\/entry\/Atom \"Atom\")** • **[Molecules](https:\/\/www.newworldencyclopedia.org\/entry\/Molecule \"Molecule\")** • **Positronium** |\n| Hypothetical elementary particles | **Superpartners:** Axino · Dilatino · Chargino · Gluino · Gravitino · Higgsino · Neutralino · Sfermion · Slepton · Squark  **Other:** Axion · Dilaton · Goldstone boson · Graviton · Higgs boson · Tachyon · X · Y · W' · Z' |\n| Hypothetical composite particles | **Exotic hadrons:** **Exotic baryons**: Pentaquark • **Exotic mesons**: Glueball · Tetraquark  **Other:** **Mesonic molecule** |\n| Quasiparticles | Davydov soliton · Exciton · Magnon · Phonon · Plasmon · Polariton · Polaron |\n\n## Credits\n*New World Encyclopedia* writers and editors rewrote and completed the *Wikipedia* article in accordance with *New World Encyclopedia* [standards](https:\/\/www.newworldencyclopedia.org\/entry\/Help:Writers_Manual \"Help:Writers Manual\"). This article abides by terms of the [Creative Commons CC-by-sa 3.0 License](https:\/\/www.newworldencyclopedia.org\/entry\/New_World_Encyclopedia:Creative_Commons_CC-by-sa_3.0 \"New World Encyclopedia:Creative Commons CC-by-sa 3.0\") (CC-by-sa), which may be used and disseminated with proper attribution. Credit is due under the terms of this license that can reference both the *New World Encyclopedia* contributors and the selfless volunteer contributors of the Wikimedia Foundation. To cite this article [click here](https:\/\/www.newworldencyclopedia.org\/entry\/Special:CiteThisPage?page=Baryon&wpFormIdentifier=titleform) for a list of acceptable citing formats.The history of earlier contributions by wikipedians is accessible to researchers here:\n\n- [Baryon](http:\/\/en.wikipedia.org\/w\/index.php?title=Baryon&oldid=236246949) [history](http:\/\/en.wikipedia.org\/w\/index.php?title=Baryon&action=history)\n- [Baryon\\_number](http:\/\/en.wikipedia.org\/w\/index.php?title=Baryon_number&oldid=230664144) [history](http:\/\/en.wikipedia.org\/w\/index.php?title=Baryon_number&action=history)\n- [Charmed\\_baryon](http:\/\/en.wikipedia.org\/w\/index.php?title=Charmed_baryon&oldid=228720132) [history](http:\/\/en.wikipedia.org\/w\/index.php?title=Charmed_baryon&action=history)\n\nThe history of this article since it was imported to *New World Encyclopedia*:\n\n- [History of \"Baryon\"](https:\/\/www.newworldencyclopedia.org\/p\/index.php?title=Baryon&action=history)\n\nNote: Some restrictions may apply to use of individual images which are separately licensed.\n\nRetrieved from <https:\/\/www.newworldencyclopedia.org\/p\/index.php?title=Baryon&oldid=1122623>\n\n[Categories](https:\/\/www.newworldencyclopedia.org\/entry\/Special:Categories \"Special:Categories\"):\n\n- [Physical sciences](https:\/\/www.newworldencyclopedia.org\/entry\/Category:Physical_sciences \"Category:Physical sciences\")\n- [Physics](https:\/\/www.newworldencyclopedia.org\/entry\/Category:Physics \"Category:Physics\")\n- [Particle physics](https:\/\/www.newworldencyclopedia.org\/entry\/Category:Particle_physics \"Category:Particle physics\")\n\nHidden category:\n\n- [Pages using ISBN magic links](https:\/\/www.newworldencyclopedia.org\/entry\/Category:Pages_using_ISBN_magic_links \"Category:Pages using ISBN magic links\")\n\n[Privacy policy](https:\/\/www.newworldencyclopedia.org\/entry\/New_World_Encyclopedia:Privacy_policy \"New World Encyclopedia:Privacy policy\")\n\n[About New World Encyclopedia](https:\/\/www.newworldencyclopedia.org\/entry\/New_World_Encyclopedia:About \"New World Encyclopedia:About\")\n\n[Disclaimers](https:\/\/www.newworldencyclopedia.org\/entry\/New_World_Encyclopedia:General_disclaimer \"New World Encyclopedia:General disclaimer\")\n\nContent is available under [Creative Commons Attribution\/Share-Alike License](https:\/\/www.newworldencyclopedia.org\/entry\/New%20World%20Encyclopedia:Creative_Commons_CC-by-sa_3.0); additional terms may apply. See [Terms of Use](https:\/\/www.newworldencyclopedia.org\/entry\/New_World_Encyclopedia:Terms_of_Use) for details.\n\n![Copyright Logo](https:\/\/static.newworldencyclopedia.org\/skins\/common\/images\/Cc.logo.circle.png)\n\n[![Powered by MediaWiki](https:\/\/www.newworldencyclopedia.org\/resources\/assets\/poweredby_mediawiki_88x31.png)](https:\/\/www.mediawiki.org\/)","attrs_readable_markdown":"[![](https:\/\/www.newworldencyclopedia.org\/d\/images\/thumb\/9\/92\/Quark_structure_proton.svg\/200px-Quark_structure_proton.svg.png)](https:\/\/www.newworldencyclopedia.org\/entry\/File:Quark_structure_proton.svg)\n\nA [proton](https:\/\/www.newworldencyclopedia.org\/entry\/Proton \"Proton\") is an example of a baryon. It is composed of 2 up quarks (u) and 1 down quark (d).\n\nThe term **baryon** usually refers to a [subatomic particle](https:\/\/www.newworldencyclopedia.org\/entry\/Subatomic_particle \"Subatomic particle\") composed of three [quarks](https:\/\/www.newworldencyclopedia.org\/entry\/Quark \"Quark\").[\\[1\\]](https:\/\/www.newworldencyclopedia.org\/entry\/Baryon#cite_note-1) A more technical (and broader) definition is that it is a subatomic particle with a baryon number of 1. Baryons are a subset of [hadrons](https:\/\/www.newworldencyclopedia.org\/entry\/Hadron \"Hadron\"), (which are particles made of quarks), and they participate in the strong interaction. They are also a subset of [fermions](https:\/\/www.newworldencyclopedia.org\/entry\/Fermion \"Fermion\"). Well-known examples of baryons are [protons](https:\/\/www.newworldencyclopedia.org\/entry\/Proton \"Proton\") and [neutrons](https:\/\/www.newworldencyclopedia.org\/entry\/Neutron \"Neutron\"), which make up [atomic nuclei](https:\/\/www.newworldencyclopedia.org\/entry\/Atomic_nucleus \"Atomic nucleus\"), but many unstable baryons have been found as well.\n\nSome \"exotic\" baryons, known as pentaquarks, are thought to be composed of four quarks and one antiquark, but their existence is not generally accepted. Each baryon has a corresponding antiparticle, called an **anti-baryon,** in which quarks are replaced by their corresponding antiquarks.\n\n## Etymology\nThe term *baryon* is derived from the [Greek](https:\/\/www.newworldencyclopedia.org\/entry\/Greek_language \"Greek language\") word *βαρύς* *(barys)*, meaning \"heavy,\" because at the time of their naming it was believed that baryons were characterized by having greater mass than other particles.\n\n## Basic properties\nEach baryon has an odd half-integer spin (such as 1 ⁄ 2 or 3 ⁄ 2), where \"spin\" refers to the angular momentum quantum number. Baryons are therefore classified as *[fermions](https:\/\/www.newworldencyclopedia.org\/entry\/Fermion \"Fermion\")*. They experience the strong nuclear force and are described by Fermi-Dirac statistics, which apply to all particles obeying the Pauli exclusion principle. This stands in contrast to [bosons](https:\/\/www.newworldencyclopedia.org\/entry\/Boson \"Boson\"), which do not obey the exclusion principle.\n\nBaryons, along with [mesons](https:\/\/www.newworldencyclopedia.org\/entry\/Meson \"Meson\"), are [hadrons](https:\/\/www.newworldencyclopedia.org\/entry\/Hadron \"Hadron\"), meaning they are particles composed of [quarks](https:\/\/www.newworldencyclopedia.org\/entry\/Quark \"Quark\"). Each quark has a baryon number of B = 1 ⁄ 3, and each antiquark has a baryon number of B = −1 ⁄ 3.\n\nThe term *baryon number* is defined as:\n\n![{\\\\displaystyle B={\\\\frac {N\\_{q}-N\\_{\\\\overline {q}}}{3}}}](https:\/\/wikimedia.org\/api\/rest_v1\/media\/math\/render\/svg\/4353f4b7742621261045bfed6830d88ce839358b)\n\nwhere\n\n![{\\\\displaystyle N\\_{q}\\\\ }](https:\/\/wikimedia.org\/api\/rest_v1\/media\/math\/render\/svg\/deedebab19fde96882032b92aeb46a667d963598) is the number of quarks, and\n\n![{\\\\displaystyle N\\_{\\\\overline {q}}}](https:\/\/wikimedia.org\/api\/rest_v1\/media\/math\/render\/svg\/6f4711277ecf2dba9a848fbb60a4f02b30b55641) is the number of antiquarks.\n\nThe term \"baryon\" is usually used for *triquarks,* that is, baryons made of three quarks. Thus, each baryon has a baryon number of 1 (B = 1 ⁄ 3 + 1 ⁄ 3 + 1 ⁄ 3 = 1).\n\nSome have suggested the existence of other, \"exotic\" baryons, such as pentaquarks—baryons made of four quarks and one antiquark (B = 1 ⁄ 3 + 1 ⁄ 3 + 1 ⁄ 3 + 1 ⁄ 3 − 1 ⁄ 3 = 1)—but their existence is not generally accepted. Theoretically, heptaquarks (5 quarks, 2 antiquarks), nonaquarks (6 quarks, 3 antiquarks), and so forth could also exist.\n\nBesides being associated with a spin number and a baryon number, each baryon has a quantum number known as *strangeness*. This quantity is equal to -1 times the number of strange quarks present in the baryon.[\\[2\\]](https:\/\/www.newworldencyclopedia.org\/entry\/Baryon#cite_note-2)\n\n## Classification\n[![](https:\/\/www.newworldencyclopedia.org\/d\/images\/thumb\/f\/f6\/Baryon_decuplet.svg\/200px-Baryon_decuplet.svg.png)](https:\/\/www.newworldencyclopedia.org\/entry\/File:Baryon_decuplet.svg)\n\nCombinations of three u, d or s-quarks with a total spin of 3\/2 form the so-called **baryon decuplet.**\n\n[![](https:\/\/www.newworldencyclopedia.org\/d\/images\/thumb\/f\/f6\/Baryon_octet.svg\/200px-Baryon_octet.svg.png)](https:\/\/www.newworldencyclopedia.org\/entry\/File:Baryon_octet.svg)\n\nThe **octet** of light spin-1\/2 baryons.\n\nBaryons are classified into groups according to their isospin values and [quark](https:\/\/www.newworldencyclopedia.org\/entry\/Quark \"Quark\") content. There are six groups of triquarks:\n\n- Nucleon (N)\n- Delta (Δ)\n- Lambda (Λ)\n- Sigma (Σ)\n- Xi (Ξ)\n- Omega (Ω)\n\nThe rules for classification are defined by the Particle Data Group. The rules cover all the particles that can be made from three of each of the six quarks (up, down, strange, charm, bottom, top), although baryons made of top quarks are not expected to exist because of the top quark's short lifetime. (The rules do not cover pentaquarks.)[\\[3\\]](https:\/\/www.newworldencyclopedia.org\/entry\/Baryon#cite_note-PDGBaryonsymbols-3) According to these rules, the [u](https:\/\/www.newworldencyclopedia.org\/p\/index.php?title=Up_quark&action=edit&redlink=1 \"Up quark (page does not exist)\"), [d](https:\/\/www.newworldencyclopedia.org\/p\/index.php?title=Down_quark&action=edit&redlink=1 \"Down quark (page does not exist)\"), and [s](https:\/\/www.newworldencyclopedia.org\/p\/index.php?title=Strange_quark&action=edit&redlink=1 \"Strange quark (page does not exist)\") quarks are considered *light,* and the [c](https:\/\/www.newworldencyclopedia.org\/p\/index.php?title=Charm_quark&action=edit&redlink=1 \"Charm quark (page does not exist)\"), [b](https:\/\/www.newworldencyclopedia.org\/p\/index.php?title=Bottom_quark&action=edit&redlink=1 \"Bottom quark (page does not exist)\"), and [t](https:\/\/www.newworldencyclopedia.org\/p\/index.php?title=Top_quark&action=edit&redlink=1 \"Top quark (page does not exist)\") quarks are considered *heavy*.\n\nBased on the rules, the following classification system has been set up:\n\n- Baryons with three [u](https:\/\/www.newworldencyclopedia.org\/p\/index.php?title=Up_quark&action=edit&redlink=1 \"Up quark (page does not exist)\") and\/or [d](https:\/\/www.newworldencyclopedia.org\/p\/index.php?title=Down_quark&action=edit&redlink=1 \"Down quark (page does not exist)\") quarks are grouped as [N](https:\/\/www.newworldencyclopedia.org\/p\/index.php?title=Nucleon&action=edit&redlink=1 \"Nucleon (page does not exist)\") (isospin\n  1\n  \n  ⁄\n  \n  2\n  ) or [Δ](https:\/\/www.newworldencyclopedia.org\/p\/index.php?title=Delta_baryon&action=edit&redlink=1 \"Delta baryon (page does not exist)\") (isospin\n  3\n  \n  ⁄\n  \n  2\n  ).\n- Baryons with two [u](https:\/\/www.newworldencyclopedia.org\/p\/index.php?title=Up_quark&action=edit&redlink=1 \"Up quark (page does not exist)\") and\/or [d](https:\/\/www.newworldencyclopedia.org\/p\/index.php?title=Down_quark&action=edit&redlink=1 \"Down quark (page does not exist)\") quarks are grouped as [Λ](https:\/\/www.newworldencyclopedia.org\/p\/index.php?title=Lambda_baryon&action=edit&redlink=1 \"Lambda baryon (page does not exist)\") (isospin 0) or [Σ](https:\/\/www.newworldencyclopedia.org\/p\/index.php?title=Sigma_baryon&action=edit&redlink=1 \"Sigma baryon (page does not exist)\") (isospin 1). If the third quark is heavy, its identity is given by a subscript.\n- Baryons with one [u](https:\/\/www.newworldencyclopedia.org\/p\/index.php?title=Up_quark&action=edit&redlink=1 \"Up quark (page does not exist)\") or [d](https:\/\/www.newworldencyclopedia.org\/p\/index.php?title=Down_quark&action=edit&redlink=1 \"Down quark (page does not exist)\") quark are placed in the group [Ξ](https:\/\/www.newworldencyclopedia.org\/p\/index.php?title=Xi_baryon&action=edit&redlink=1 \"Xi baryon (page does not exist)\") (isospin\n  1\n  \n  ⁄\n  \n  2\n  ). One or two subscripts are used if one or both of the remaining quarks are heavy.\n- Baryons with no [u](https:\/\/www.newworldencyclopedia.org\/p\/index.php?title=Up_quark&action=edit&redlink=1 \"Up quark (page does not exist)\") or [d](https:\/\/www.newworldencyclopedia.org\/p\/index.php?title=Down_quark&action=edit&redlink=1 \"Down quark (page does not exist)\") quarks are placed in the group [Ω](https:\/\/www.newworldencyclopedia.org\/p\/index.php?title=Omega_baryon&action=edit&redlink=1 \"Omega baryon (page does not exist)\") (isospin 0), and subscripts indicate any heavy quark content.\n- Some baryons decay strongly, in which case their masses are shown as part of their names. For example, Sigmas (Σ) and Omegas (Ω) do not decay strongly, but Deltas (Δ(1232)), and charmed Xis (Ξ\\+c(2645)) do.\n\nGiven that quarks carry charge, knowledge of the charge of a particle indirectly gives the quark content. For example, the rules say that the Σb contains a bottom and some combination of two up and\/or down quarks. A Σ0b must be one up quark (Q=2 ⁄ 3), one down quark (Q=−1 ⁄ 3), and one bottom quark (Q=−1 ⁄ 3) to have the correct charge (Q=0).\n\nThe number of baryons within one group (excluding resonances) is given by the number of isospin projections possible (2 × isospin + 1). For example, there are four Δ's, corresponding to the four isospin projections of the isospin value I = 3 ⁄ 2: Δ\\++ (Iz = 3 ⁄ 2), Δ\\+(Iz = 1 ⁄ 2), Δ0(Iz = −1 ⁄ 2), and Δ−(Iz = −3 ⁄ 2). Another example would be the three Σb's, corresponding to the three isospin projections of the isospin value I = 1: Σ\\+b (Iz = 1), Σ0b(Iz = 0), and Σ−b(Iz = −1).\n\n### Charmed baryons\nBaryons that are composed of at least one charm quark are known as *charmed baryons*.\n\n## Baryonic matter\n**Baryonic [matter](https:\/\/www.newworldencyclopedia.org\/entry\/Matter \"Matter\")** is matter composed mostly of baryons (by mass). It includes [atoms](https:\/\/www.newworldencyclopedia.org\/entry\/Atom \"Atom\") of all types, and thus includes nearly all types of matter that we may encounter or experience in everyday life, including the matter that constitutes human bodies. **Non-baryonic matter,** as implied by the name, is any sort of matter that is not primarily composed of baryons. It may include such ordinary matter as neutrinos or free [electrons](https:\/\/www.newworldencyclopedia.org\/entry\/Electron \"Electron\"), but it may also include exotic species of non-baryonic [dark matter](https:\/\/www.newworldencyclopedia.org\/entry\/Dark_matter \"Dark matter\"), such as supersymmetric particles, axions, or black holes.\n\nThe distinction between baryonic and non-baryonic matter is important in cosmology, because Big Bang nucleosynthesis models set tight constraints on the amount of baryonic matter present in the early [universe](https:\/\/www.newworldencyclopedia.org\/entry\/Universe \"Universe\").\n\nThe very existence of baryons is also a significant issue in cosmology because current theory assumes that the Big Bang produced a state with equal amounts of baryons and anti-baryons. The process by which baryons came to outnumber their antiparticles is called *baryogenesis*. (This is distinct from a process by which [leptons](https:\/\/www.newworldencyclopedia.org\/entry\/Lepton \"Lepton\") account for the predominance of matter over antimatter, known as *leptogenesis*.)\n\n## Baryogenesis\nExperiments are consistent with the number of quarks in the universe being a constant and, more specifically, the number of [baryons]() being a constant; in technical language, the total baryon number appears to be *conserved.* Within the prevailing [Standard Model](https:\/\/www.newworldencyclopedia.org\/entry\/Standard_Model \"Standard Model\") of particle physics, the number of baryons may change in multiples of three due to the action of sphalerons, although this is rare and has not been observed experimentally. Some grand unified theories of particle physics also predict that a single [proton](https:\/\/www.newworldencyclopedia.org\/entry\/Proton \"Proton\") can decay, changing the baryon number by one; however, this has not yet been observed experimentally. The excess of baryons over antibaryons in the present universe is thought to be due to non-conservation of baryon number in the very early universe, though this is not well understood.\n\n## See also\n- [Antimatter](https:\/\/www.newworldencyclopedia.org\/entry\/Antimatter \"Antimatter\")\n- [Atom](https:\/\/www.newworldencyclopedia.org\/entry\/Atom \"Atom\")\n- [Dark matter](https:\/\/www.newworldencyclopedia.org\/entry\/Dark_matter \"Dark matter\")\n- [Fermion](https:\/\/www.newworldencyclopedia.org\/entry\/Fermion \"Fermion\")\n- [Hadron](https:\/\/www.newworldencyclopedia.org\/entry\/Hadron \"Hadron\")\n- [Lepton](https:\/\/www.newworldencyclopedia.org\/entry\/Lepton \"Lepton\")\n- [Matter](https:\/\/www.newworldencyclopedia.org\/entry\/Matter \"Matter\")\n- [Meson](https:\/\/www.newworldencyclopedia.org\/entry\/Meson \"Meson\")\n- [Neutron](https:\/\/www.newworldencyclopedia.org\/entry\/Neutron \"Neutron\")\n- [Particle physics](https:\/\/www.newworldencyclopedia.org\/entry\/Particle_physics \"Particle physics\")\n- [Proton](https:\/\/www.newworldencyclopedia.org\/entry\/Proton \"Proton\")\n- [Quark](https:\/\/www.newworldencyclopedia.org\/entry\/Quark \"Quark\")\n- [Standard Model](https:\/\/www.newworldencyclopedia.org\/entry\/Standard_Model \"Standard Model\")\n- [Subatomic particle](https:\/\/www.newworldencyclopedia.org\/entry\/Subatomic_particle \"Subatomic particle\")\n## Notes\n1. [↑](https:\/\/www.newworldencyclopedia.org\/entry\/Baryon#cite_ref-1) The Particle Adventure, [Hadrons: Baryons and Mesons.](http:\/\/www.particleadventure.org\/frameless\/hadrons.html) Retrieved September 10, 2008.\n2. [↑](https:\/\/www.newworldencyclopedia.org\/entry\/Baryon#cite_ref-2) Hyper Physics, [Baryons.](http:\/\/hyperphysics.phy-astr.gsu.edu\/Hbase\/particles\/hadron.html) Retrieved September 10, 2008.\n3. [↑](https:\/\/www.newworldencyclopedia.org\/entry\/Baryon#cite_ref-PDGBaryonsymbols_3-0) M. Roos and C.G. Wohl, [Naming Scheme for Hadrons,](http:\/\/pdg.lbl.gov\/2007\/reviews\/namingrpp.pdf) *J. Phys* G 33:1. Retrieved September 10, 2008.\n## ReferencesISBN links support NWE through referral fees\n- Cottingham, W.N., and D.A. Greenwood. *An Introduction to the Standard Model of Particle Physics,* 2nd edition. Cambridge: Cambridge University Press, 2007. [ISBN 978-0521852494](https:\/\/www.amazon.com\/gp\/product\/0521852498\/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0521852498&linkCode=as2&tag=newworldencyc-20&linkId=83df4bed72539f2a52beb06a1d71be79)\n- Griffiths, David J. *Introduction to Elementary Particles*. New York: Wiley, 1987. [ISBN 0471603864](https:\/\/www.amazon.com\/gp\/product\/0471603864\/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0471603864&linkCode=as2&tag=newworldencyc-20&linkId=83df4bed72539f2a52beb06a1d71be79)\n- Halzen, Francis, and Alan D. Martin. *Quarks and Leptons: An Introductory Course in Modern Particle Physics*. New York: Wiley, 1984. [ISBN 0471887412](https:\/\/www.amazon.com\/gp\/product\/0471887412\/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0471887412&linkCode=as2&tag=newworldencyc-20&linkId=83df4bed72539f2a52beb06a1d71be79)\n- Martin, B. R. *Nuclear and Particle Physics: An Introduction*. Chichester: John Wiley, 2006. [ISBN 978-0470025321](https:\/\/www.amazon.com\/gp\/product\/0470025328\/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0470025328&linkCode=as2&tag=newworldencyc-20&linkId=83df4bed72539f2a52beb06a1d71be79)\n- Povh, Bogdan. *Particles and Nuclei: An Introduction to the Physical Concepts*. Berlin: Springer-Verlag, 1995. [ISBN 0387594396](https:\/\/www.amazon.com\/gp\/product\/0387594396\/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0387594396&linkCode=as2&tag=newworldencyc-20&linkId=83df4bed72539f2a52beb06a1d71be79)\n- Veltman, Martinus. *Facts and Mysteries in Elementary Particle Physics.* River Edge, NJ: World Scientific, 2003. [ISBN 981238149X](https:\/\/www.amazon.com\/gp\/product\/981238149X\/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=981238149X&linkCode=as2&tag=newworldencyc-20&linkId=83df4bed72539f2a52beb06a1d71be79)\n## External links\nAll links retrieved September 20, 2023.\n\n- [Baryons](http:\/\/hyperphysics.phy-astr.gsu.edu\/Hbase\/particles\/hadron.html).\n- [Table of Baryons](http:\/\/hyperphysics.phy-astr.gsu.edu\/hbase\/particles\/baryon.html#c1).\n- [The Review of Particle Physics](http:\/\/pdg.lbl.gov\/). Particle Data Group.\n***\n| Particles in physics |   |\n|---|---|\n| [elementary particles](https:\/\/www.newworldencyclopedia.org\/entry\/Elementary_particle \"Elementary particle\") | **Elementary [fermions](https:\/\/www.newworldencyclopedia.org\/entry\/Fermion \"Fermion\"):** **[Quarks](https:\/\/www.newworldencyclopedia.org\/entry\/Quark \"Quark\")**: u · d · s · c · b · t • **[Leptons](https:\/\/www.newworldencyclopedia.org\/entry\/Lepton \"Lepton\")**: [e](https:\/\/www.newworldencyclopedia.org\/entry\/Electron \"Electron\") · μ · τ · [νe · νμ · ντ](https:\/\/www.newworldencyclopedia.org\/p\/index.php?title=Neutrino&action=edit&redlink=1 \"Neutrino (page does not exist)\")  **Elementary [bosons](https:\/\/www.newworldencyclopedia.org\/entry\/Boson \"Boson\"):** **Gauge bosons**: [γ](https:\/\/www.newworldencyclopedia.org\/entry\/Photon \"Photon\") · g · [W± · Z0](https:\/\/www.newworldencyclopedia.org\/p\/index.php?title=W_and_Z_bosons&action=edit&redlink=1 \"W and Z bosons (page does not exist)\") • **Ghosts** |\n| Composite particles | **[Hadrons](https:\/\/www.newworldencyclopedia.org\/entry\/Hadron \"Hadron\"):** **[Baryons]()**(list)\/**Hyperons**\/**Nucleons**: [p](https:\/\/www.newworldencyclopedia.org\/entry\/Proton \"Proton\") · [n](https:\/\/www.newworldencyclopedia.org\/entry\/Neutron \"Neutron\") · Δ · Λ · Σ · Ξ · Ω · [Ξb](https:\/\/www.newworldencyclopedia.org\/p\/index.php?title=Cascade_B&action=edit&redlink=1 \"Cascade B (page does not exist)\") • **[Mesons](https:\/\/www.newworldencyclopedia.org\/entry\/Meson \"Meson\")**(list)\/**Quarkonia**: π · K · ρ · J\/ψ · Υ  **Other:** **[Atomic nucleus](https:\/\/www.newworldencyclopedia.org\/entry\/Atomic_nucleus \"Atomic nucleus\")** • **[Atoms](https:\/\/www.newworldencyclopedia.org\/entry\/Atom \"Atom\")** • **[Molecules](https:\/\/www.newworldencyclopedia.org\/entry\/Molecule \"Molecule\")** • **Positronium** |\n| Hypothetical elementary particles | **Superpartners:** Axino · Dilatino · Chargino · Gluino · Gravitino · Higgsino · Neutralino · Sfermion · Slepton · Squark  **Other:** Axion · Dilaton · Goldstone boson · Graviton · Higgs boson · Tachyon · X · Y · W' · Z' |\n| Hypothetical composite particles | **Exotic hadrons:** **Exotic baryons**: Pentaquark • **Exotic mesons**: Glueball · Tetraquark  **Other:** **Mesonic molecule** |\n| Quasiparticles | Davydov soliton · Exciton · Magnon · Phonon · Plasmon · Polariton · Polaron |\n\n## Credits\n*New World Encyclopedia* writers and editors rewrote and completed the *Wikipedia* article in accordance with *New World Encyclopedia* [standards](https:\/\/www.newworldencyclopedia.org\/entry\/Help:Writers_Manual \"Help:Writers Manual\"). This article abides by terms of the [Creative Commons CC-by-sa 3.0 License](https:\/\/www.newworldencyclopedia.org\/entry\/New_World_Encyclopedia:Creative_Commons_CC-by-sa_3.0 \"New World Encyclopedia:Creative Commons CC-by-sa 3.0\") (CC-by-sa), which may be used and disseminated with proper attribution. Credit is due under the terms of this license that can reference both the *New World Encyclopedia* contributors and the selfless volunteer contributors of the Wikimedia Foundation. To cite this article [click here](https:\/\/www.newworldencyclopedia.org\/entry\/Special:CiteThisPage?page=Baryon&wpFormIdentifier=titleform) for a list of acceptable citing formats.The history of earlier contributions by wikipedians is accessible to researchers here:\n\n- [Baryon](http:\/\/en.wikipedia.org\/w\/index.php?title=Baryon&oldid=236246949) [history](http:\/\/en.wikipedia.org\/w\/index.php?title=Baryon&action=history)\n- [Baryon\\_number](http:\/\/en.wikipedia.org\/w\/index.php?title=Baryon_number&oldid=230664144) [history](http:\/\/en.wikipedia.org\/w\/index.php?title=Baryon_number&action=history)\n- [Charmed\\_baryon](http:\/\/en.wikipedia.org\/w\/index.php?title=Charmed_baryon&oldid=228720132) [history](http:\/\/en.wikipedia.org\/w\/index.php?title=Charmed_baryon&action=history)\n\nThe history of this article since it was imported to *New World Encyclopedia*:\n\n- [History of \"Baryon\"](https:\/\/www.newworldencyclopedia.org\/p\/index.php?title=Baryon&action=history)\n\nNote: Some restrictions may apply to use of individual images which are separately licensed.","meta_canonical":null}

3. Robots.txt Check

Query:

Response:

4. Spam/Ban Check

Query:

Response:

5. Seen Status Check

ℹ️ Skipped - page is already crawled

📄

INDEXABLE

✅

CRAWLED

6 hours ago

🤖

ROBOTS ALLOWED

Page Info Filters

Filter	Status	Condition	Details
HTTP status	PASS	`download_http_code = 200`	HTTP 200
Age cutoff	PASS	`download_stamp > now() - 6 MONTH`	0 months ago
History drop	PASS	`isNull(history_drop_reason)`	No drop reason
Spam/ban	PASS	`fh_dont_index != 1 AND ml_spam_score = 0`	ml_spam_score=0
Canonical	PASS	`meta_canonical IS NULL OR = '' OR = src_unparsed`	Not set

Page Details

Property	Value
URL	https://www.newworldencyclopedia.org/entry/Baryon
Last Crawled	2026-04-18 03:53:47 (6 hours ago)
First Indexed	2013-08-11 04:04:06 (12 years ago)
HTTP Status Code	200
Meta Title	Baryon - New World Encyclopedia
Meta Description	null
Meta Canonical	null
Boilerpipe Text	A proton is an example of a baryon. It is composed of 2 up quarks (u) and 1 down quark (d). The term baryon usually refers to a subatomic particle composed of three quarks . [1] A more technical (and broader) definition is that it is a subatomic particle with a baryon number of 1. Baryons are a subset of hadrons , (which are particles made of quarks), and they participate in the strong interaction. They are also a subset of fermions . Well-known examples of baryons are protons and neutrons , which make up atomic nuclei , but many unstable baryons have been found as well. Some "exotic" baryons, known as pentaquarks, are thought to be composed of four quarks and one antiquark, but their existence is not generally accepted. Each baryon has a corresponding antiparticle, called an anti-baryon, in which quarks are replaced by their corresponding antiquarks. Etymology The term baryon is derived from the Greek word βαρύς (barys) , meaning "heavy," because at the time of their naming it was believed that baryons were characterized by having greater mass than other particles. Basic properties Each baryon has an odd half-integer spin (such as 1 ⁄ 2 or 3 ⁄ 2 ), where "spin" refers to the angular momentum quantum number. Baryons are therefore classified as fermions . They experience the strong nuclear force and are described by Fermi-Dirac statistics, which apply to all particles obeying the Pauli exclusion principle. This stands in contrast to bosons , which do not obey the exclusion principle. Baryons, along with mesons , are hadrons , meaning they are particles composed of quarks . Each quark has a baryon number of B = 1 ⁄ 3 , and each antiquark has a baryon number of B = − 1 ⁄ 3 . The term baryon number is defined as: where is the number of quarks, and is the number of antiquarks. The term "baryon" is usually used for triquarks, that is, baryons made of three quarks. Thus, each baryon has a baryon number of 1 (B = 1 ⁄ 3 + 1 ⁄ 3 + 1 ⁄ 3 = 1). Some have suggested the existence of other, "exotic" baryons, such as pentaquarks—baryons made of four quarks and one antiquark (B = 1 ⁄ 3 + 1 ⁄ 3 + 1 ⁄ 3 + 1 ⁄ 3 − 1 ⁄ 3 = 1)—but their existence is not generally accepted. Theoretically, heptaquarks (5 quarks, 2 antiquarks), nonaquarks (6 quarks, 3 antiquarks), and so forth could also exist. Besides being associated with a spin number and a baryon number, each baryon has a quantum number known as strangeness . This quantity is equal to -1 times the number of strange quarks present in the baryon. [2] Classification Combinations of three u, d or s-quarks with a total spin of 3/2 form the so-called baryon decuplet. The octet of light spin-1/2 baryons. Baryons are classified into groups according to their isospin values and quark content. There are six groups of triquarks: Nucleon ( N ) Delta ( Δ ) Lambda ( Λ ) Sigma ( Σ ) Xi ( Ξ ) Omega ( Ω ) The rules for classification are defined by the Particle Data Group. The rules cover all the particles that can be made from three of each of the six quarks (up, down, strange, charm, bottom, top), although baryons made of top quarks are not expected to exist because of the top quark's short lifetime. (The rules do not cover pentaquarks.) [3] According to these rules, the u , d , and s quarks are considered light, and the c , b , and t quarks are considered heavy . Based on the rules, the following classification system has been set up: Baryons with three u and/or d quarks are grouped as N (isospin 1 ⁄ 2 ) or Δ (isospin 3 ⁄ 2 ). Baryons with two u and/or d quarks are grouped as Λ (isospin 0) or Σ (isospin 1). If the third quark is heavy, its identity is given by a subscript. Baryons with one u or d quark are placed in the group Ξ (isospin 1 ⁄ 2 ). One or two subscripts are used if one or both of the remaining quarks are heavy. Baryons with no u or d quarks are placed in the group Ω (isospin 0), and subscripts indicate any heavy quark content. Some baryons decay strongly, in which case their masses are shown as part of their names. For example, Sigmas ( Σ ) and Omegas ( Ω ) do not decay strongly, but Deltas ( Δ (1232) ), and charmed Xis ( Ξ + c (2645) ) do. Given that quarks carry charge, knowledge of the charge of a particle indirectly gives the quark content. For example, the rules say that the Σ b contains a bottom and some combination of two up and/or down quarks. A Σ 0 b must be one up quark (Q= 2 ⁄ 3 ), one down quark (Q=− 1 ⁄ 3 ), and one bottom quark (Q=− 1 ⁄ 3 ) to have the correct charge (Q=0). The number of baryons within one group (excluding resonances) is given by the number of isospin projections possible (2 × isospin + 1). For example, there are four Δ 's, corresponding to the four isospin projections of the isospin value I = 3 ⁄ 2 : Δ ++ (I z = 3 ⁄ 2 ), Δ + (I z = 1 ⁄ 2 ), Δ 0 (I z = − 1 ⁄ 2 ), and Δ − (I z = − 3 ⁄ 2 ). Another example would be the three Σ b 's, corresponding to the three isospin projections of the isospin value I = 1: Σ + b (I z = 1), Σ 0 b (I z = 0), and Σ − b (I z = −1). Charmed baryons Baryons that are composed of at least one charm quark are known as charmed baryons . Baryonic matter Baryonic matter is matter composed mostly of baryons (by mass). It includes atoms of all types, and thus includes nearly all types of matter that we may encounter or experience in everyday life, including the matter that constitutes human bodies. Non-baryonic matter, as implied by the name, is any sort of matter that is not primarily composed of baryons. It may include such ordinary matter as neutrinos or free electrons , but it may also include exotic species of non-baryonic dark matter , such as supersymmetric particles, axions, or black holes. The distinction between baryonic and non-baryonic matter is important in cosmology, because Big Bang nucleosynthesis models set tight constraints on the amount of baryonic matter present in the early universe . The very existence of baryons is also a significant issue in cosmology because current theory assumes that the Big Bang produced a state with equal amounts of baryons and anti-baryons. The process by which baryons came to outnumber their antiparticles is called baryogenesis . (This is distinct from a process by which leptons account for the predominance of matter over antimatter, known as leptogenesis .) Baryogenesis Experiments are consistent with the number of quarks in the universe being a constant and, more specifically, the number of baryons being a constant; in technical language, the total baryon number appears to be conserved. Within the prevailing Standard Model of particle physics, the number of baryons may change in multiples of three due to the action of sphalerons, although this is rare and has not been observed experimentally. Some grand unified theories of particle physics also predict that a single proton can decay, changing the baryon number by one; however, this has not yet been observed experimentally. The excess of baryons over antibaryons in the present universe is thought to be due to non-conservation of baryon number in the very early universe, though this is not well understood. See also Antimatter Atom Dark matter Fermion Hadron Lepton Matter Meson Neutron Particle physics Proton Quark Standard Model Subatomic particle Notes ↑ The Particle Adventure, Hadrons: Baryons and Mesons. Retrieved September 10, 2008. ↑ Hyper Physics, Baryons. Retrieved September 10, 2008. ↑ M. Roos and C.G. Wohl, Naming Scheme for Hadrons, J. Phys G 33:1. Retrieved September 10, 2008. References ISBN links support NWE through referral fees Cottingham, W.N., and D.A. Greenwood. An Introduction to the Standard Model of Particle Physics, 2nd edition. Cambridge: Cambridge University Press, 2007. ISBN 978-0521852494 Griffiths, David J. Introduction to Elementary Particles . New York: Wiley, 1987. ISBN 0471603864 Halzen, Francis, and Alan D. Martin. Quarks and Leptons: An Introductory Course in Modern Particle Physics . New York: Wiley, 1984. ISBN 0471887412 Martin, B. R. Nuclear and Particle Physics: An Introduction . Chichester: John Wiley, 2006. ISBN 978-0470025321 Povh, Bogdan. Particles and Nuclei: An Introduction to the Physical Concepts . Berlin: Springer-Verlag, 1995. ISBN 0387594396 Veltman, Martinus. Facts and Mysteries in Elementary Particle Physics. River Edge, NJ: World Scientific, 2003. ISBN 981238149X External links All links retrieved September 20, 2023. Baryons . Table of Baryons . The Review of Particle Physics . Particle Data Group. Particles in physics elementary particles Elementary fermions : Quarks : u · d · s · c · b · t • Leptons : e · μ · τ · ν e · ν μ · ν τ Elementary bosons : Gauge bosons : γ · g · W ± · Z 0 • Ghosts Composite particles Hadrons : Baryons (list)/ Hyperons / Nucleons : p · n · Δ · Λ · Σ · Ξ · Ω · Ξ b • Mesons (list)/ Quarkonia : π · K · ρ · J/ψ · Υ Other: Atomic nucleus • Atoms • Molecules • Positronium Hypothetical elementary particles Superpartners: Axino · Dilatino · Chargino · Gluino · Gravitino · Higgsino · Neutralino · Sfermion · Slepton · Squark Other: Axion · Dilaton · Goldstone boson · Graviton · Higgs boson · Tachyon · X · Y · W' · Z' Hypothetical composite particles Exotic hadrons: Exotic baryons : Pentaquark • Exotic mesons : Glueball · Tetraquark Other: Mesonic molecule Quasiparticles Davydov soliton · Exciton · Magnon · Phonon · Plasmon · Polariton · Polaron Credits New World Encyclopedia writers and editors rewrote and completed the Wikipedia article in accordance with New World Encyclopedia standards . This article abides by terms of the Creative Commons CC-by-sa 3.0 License (CC-by-sa), which may be used and disseminated with proper attribution. Credit is due under the terms of this license that can reference both the New World Encyclopedia contributors and the selfless volunteer contributors of the Wikimedia Foundation. To cite this article click here for a list of acceptable citing formats.The history of earlier contributions by wikipedians is accessible to researchers here: Baryon history Baryon_number history Charmed_baryon history The history of this article since it was imported to New World Encyclopedia : History of "Baryon" Note: Some restrictions may apply to use of individual images which are separately licensed.
Markdown	[![Research Begins Here](https://www.newworldencyclopedia.org/images/nwe_header.jpg)](https://www.newworldencyclopedia.org/ "Visit the main page") [Articles](https://www.newworldencyclopedia.org/entry/Category:Copyedited) [About](https://www.newworldencyclopedia.org/entry/Info:Project_Vision) [Feedback](https://www.newworldencyclopedia.org/feedback/baryon) # Baryon From New World Encyclopedia Jump to:[navigation](https://www.newworldencyclopedia.org/entry/Baryon#mw-navigation), [search](https://www.newworldencyclopedia.org/entry/Baryon#p-search) [Previous (Baruch Spinoza)](https://www.newworldencyclopedia.org/entry/Baruch_Spinoza "Baruch Spinoza") [Next (Basalt)](https://www.newworldencyclopedia.org/entry/Basalt "Basalt") [![](https://www.newworldencyclopedia.org/d/images/thumb/9/92/Quark_structure_proton.svg/200px-Quark_structure_proton.svg.png)](https://www.newworldencyclopedia.org/entry/File:Quark_structure_proton.svg) A [proton](https://www.newworldencyclopedia.org/entry/Proton "Proton") is an example of a baryon. It is composed of 2 up quarks (u) and 1 down quark (d). The term baryon usually refers to a [subatomic particle](https://www.newworldencyclopedia.org/entry/Subatomic_particle "Subatomic particle") composed of three [quarks](https://www.newworldencyclopedia.org/entry/Quark "Quark").[\[1\]](https://www.newworldencyclopedia.org/entry/Baryon#cite_note-1) A more technical (and broader) definition is that it is a subatomic particle with a baryon number of 1. Baryons are a subset of [hadrons](https://www.newworldencyclopedia.org/entry/Hadron "Hadron"), (which are particles made of quarks), and they participate in the strong interaction. They are also a subset of [fermions](https://www.newworldencyclopedia.org/entry/Fermion "Fermion"). Well-known examples of baryons are [protons](https://www.newworldencyclopedia.org/entry/Proton "Proton") and [neutrons](https://www.newworldencyclopedia.org/entry/Neutron "Neutron"), which make up [atomic nuclei](https://www.newworldencyclopedia.org/entry/Atomic_nucleus "Atomic nucleus"), but many unstable baryons have been found as well. ## Contents - [1 Etymology](https://www.newworldencyclopedia.org/entry/Baryon#Etymology) - [2 Basic properties](https://www.newworldencyclopedia.org/entry/Baryon#Basic_properties) - [3 Classification](https://www.newworldencyclopedia.org/entry/Baryon#Classification) - [3\.1 Charmed baryons](https://www.newworldencyclopedia.org/entry/Baryon#Charmed_baryons) - [4 Baryonic matter](https://www.newworldencyclopedia.org/entry/Baryon#Baryonic_matter) - [5 Baryogenesis](https://www.newworldencyclopedia.org/entry/Baryon#Baryogenesis) - [6 See also](https://www.newworldencyclopedia.org/entry/Baryon#See_also) - [7 Notes](https://www.newworldencyclopedia.org/entry/Baryon#Notes) - [8 References](https://www.newworldencyclopedia.org/entry/Baryon#References) - [9 External links](https://www.newworldencyclopedia.org/entry/Baryon#External_links) - [10 Credits](https://www.newworldencyclopedia.org/entry/Baryon#Credits) Some "exotic" baryons, known as pentaquarks, are thought to be composed of four quarks and one antiquark, but their existence is not generally accepted. Each baryon has a corresponding antiparticle, called an anti-baryon, in which quarks are replaced by their corresponding antiquarks. ## Etymology The term baryon is derived from the [Greek](https://www.newworldencyclopedia.org/entry/Greek_language "Greek language") word βαρύς (barys), meaning "heavy," because at the time of their naming it was believed that baryons were characterized by having greater mass than other particles. ## Basic properties Each baryon has an odd half-integer spin (such as 1 ⁄ 2 or 3 ⁄ 2), where "spin" refers to the angular momentum quantum number. Baryons are therefore classified as [fermions](https://www.newworldencyclopedia.org/entry/Fermion "Fermion"). They experience the strong nuclear force and are described by Fermi-Dirac statistics, which apply to all particles obeying the Pauli exclusion principle. This stands in contrast to [bosons](https://www.newworldencyclopedia.org/entry/Boson "Boson"), which do not obey the exclusion principle. Baryons, along with [mesons](https://www.newworldencyclopedia.org/entry/Meson "Meson"), are [hadrons](https://www.newworldencyclopedia.org/entry/Hadron "Hadron"), meaning they are particles composed of [quarks](https://www.newworldencyclopedia.org/entry/Quark "Quark"). Each quark has a baryon number of B = 1 ⁄ 3, and each antiquark has a baryon number of B = −1 ⁄ 3. The term baryon number is defined as: B \= N q − N q ¯ 3 {\\displaystyle B={\\frac {N\_{q}-N\_{\\overline {q}}}{3}}} ![{\\displaystyle B={\\frac {N\_{q}-N\_{\\overline {q}}}{3}}}](https://wikimedia.org/api/rest_v1/media/math/render/svg/4353f4b7742621261045bfed6830d88ce839358b) where N q {\\displaystyle N\_{q}\\ } ![{\\displaystyle N\_{q}\\ }](https://wikimedia.org/api/rest_v1/media/math/render/svg/deedebab19fde96882032b92aeb46a667d963598) is the number of quarks, and N q ¯ {\\displaystyle N\_{\\overline {q}}} ![{\\displaystyle N\_{\\overline {q}}}](https://wikimedia.org/api/rest_v1/media/math/render/svg/6f4711277ecf2dba9a848fbb60a4f02b30b55641) is the number of antiquarks. The term "baryon" is usually used for triquarks, that is, baryons made of three quarks. Thus, each baryon has a baryon number of 1 (B = 1 ⁄ 3 + 1 ⁄ 3 + 1 ⁄ 3 = 1). Some have suggested the existence of other, "exotic" baryons, such as pentaquarks—baryons made of four quarks and one antiquark (B = 1 ⁄ 3 + 1 ⁄ 3 + 1 ⁄ 3 + 1 ⁄ 3 − 1 ⁄ 3 = 1)—but their existence is not generally accepted. Theoretically, heptaquarks (5 quarks, 2 antiquarks), nonaquarks (6 quarks, 3 antiquarks), and so forth could also exist. Besides being associated with a spin number and a baryon number, each baryon has a quantum number known as strangeness. This quantity is equal to -1 times the number of strange quarks present in the baryon.[\[2\]](https://www.newworldencyclopedia.org/entry/Baryon#cite_note-2) ## Classification [![](https://www.newworldencyclopedia.org/d/images/thumb/f/f6/Baryon_decuplet.svg/200px-Baryon_decuplet.svg.png)](https://www.newworldencyclopedia.org/entry/File:Baryon_decuplet.svg) Combinations of three u, d or s-quarks with a total spin of 3/2 form the so-called baryon decuplet. [![](https://www.newworldencyclopedia.org/d/images/thumb/f/f6/Baryon_octet.svg/200px-Baryon_octet.svg.png)](https://www.newworldencyclopedia.org/entry/File:Baryon_octet.svg) The octet of light spin-1/2 baryons. Baryons are classified into groups according to their isospin values and [quark](https://www.newworldencyclopedia.org/entry/Quark "Quark") content. There are six groups of triquarks: - Nucleon (N) - Delta (Δ) - Lambda (Λ) - Sigma (Σ) - Xi (Ξ) - Omega (Ω) The rules for classification are defined by the Particle Data Group. The rules cover all the particles that can be made from three of each of the six quarks (up, down, strange, charm, bottom, top), although baryons made of top quarks are not expected to exist because of the top quark's short lifetime. (The rules do not cover pentaquarks.)[\[3\]](https://www.newworldencyclopedia.org/entry/Baryon#cite_note-PDGBaryonsymbols-3) According to these rules, the [u](https://www.newworldencyclopedia.org/p/index.php?title=Up_quark&action=edit&redlink=1 "Up quark (page does not exist)"), [d](https://www.newworldencyclopedia.org/p/index.php?title=Down_quark&action=edit&redlink=1 "Down quark (page does not exist)"), and [s](https://www.newworldencyclopedia.org/p/index.php?title=Strange_quark&action=edit&redlink=1 "Strange quark (page does not exist)") quarks are considered light, and the [c](https://www.newworldencyclopedia.org/p/index.php?title=Charm_quark&action=edit&redlink=1 "Charm quark (page does not exist)"), [b](https://www.newworldencyclopedia.org/p/index.php?title=Bottom_quark&action=edit&redlink=1 "Bottom quark (page does not exist)"), and [t](https://www.newworldencyclopedia.org/p/index.php?title=Top_quark&action=edit&redlink=1 "Top quark (page does not exist)") quarks are considered heavy. Based on the rules, the following classification system has been set up: - Baryons with three [u](https://www.newworldencyclopedia.org/p/index.php?title=Up_quark&action=edit&redlink=1 "Up quark (page does not exist)") and/or [d](https://www.newworldencyclopedia.org/p/index.php?title=Down_quark&action=edit&redlink=1 "Down quark (page does not exist)") quarks are grouped as [N](https://www.newworldencyclopedia.org/p/index.php?title=Nucleon&action=edit&redlink=1 "Nucleon (page does not exist)") (isospin 1 ⁄ 2 ) or [Δ](https://www.newworldencyclopedia.org/p/index.php?title=Delta_baryon&action=edit&redlink=1 "Delta baryon (page does not exist)") (isospin 3 ⁄ 2 ). - Baryons with two [u](https://www.newworldencyclopedia.org/p/index.php?title=Up_quark&action=edit&redlink=1 "Up quark (page does not exist)") and/or [d](https://www.newworldencyclopedia.org/p/index.php?title=Down_quark&action=edit&redlink=1 "Down quark (page does not exist)") quarks are grouped as [Λ](https://www.newworldencyclopedia.org/p/index.php?title=Lambda_baryon&action=edit&redlink=1 "Lambda baryon (page does not exist)") (isospin 0) or [Σ](https://www.newworldencyclopedia.org/p/index.php?title=Sigma_baryon&action=edit&redlink=1 "Sigma baryon (page does not exist)") (isospin 1). If the third quark is heavy, its identity is given by a subscript. - Baryons with one [u](https://www.newworldencyclopedia.org/p/index.php?title=Up_quark&action=edit&redlink=1 "Up quark (page does not exist)") or [d](https://www.newworldencyclopedia.org/p/index.php?title=Down_quark&action=edit&redlink=1 "Down quark (page does not exist)") quark are placed in the group [Ξ](https://www.newworldencyclopedia.org/p/index.php?title=Xi_baryon&action=edit&redlink=1 "Xi baryon (page does not exist)") (isospin 1 ⁄ 2 ). One or two subscripts are used if one or both of the remaining quarks are heavy. - Baryons with no [u](https://www.newworldencyclopedia.org/p/index.php?title=Up_quark&action=edit&redlink=1 "Up quark (page does not exist)") or [d](https://www.newworldencyclopedia.org/p/index.php?title=Down_quark&action=edit&redlink=1 "Down quark (page does not exist)") quarks are placed in the group [Ω](https://www.newworldencyclopedia.org/p/index.php?title=Omega_baryon&action=edit&redlink=1 "Omega baryon (page does not exist)") (isospin 0), and subscripts indicate any heavy quark content. - Some baryons decay strongly, in which case their masses are shown as part of their names. For example, Sigmas (Σ) and Omegas (Ω) do not decay strongly, but Deltas (Δ(1232)), and charmed Xis (Ξ\+c(2645)) do. Given that quarks carry charge, knowledge of the charge of a particle indirectly gives the quark content. For example, the rules say that the Σb contains a bottom and some combination of two up and/or down quarks. A Σ0b must be one up quark (Q=2 ⁄ 3), one down quark (Q=−1 ⁄ 3), and one bottom quark (Q=−1 ⁄ 3) to have the correct charge (Q=0). The number of baryons within one group (excluding resonances) is given by the number of isospin projections possible (2 × isospin + 1). For example, there are four Δ's, corresponding to the four isospin projections of the isospin value I = 3 ⁄ 2: Δ\++ (Iz = 3 ⁄ 2), Δ\+(Iz = 1 ⁄ 2), Δ0(Iz = −1 ⁄ 2), and Δ−(Iz = −3 ⁄ 2). Another example would be the three Σb's, corresponding to the three isospin projections of the isospin value I = 1: Σ\+b (Iz = 1), Σ0b(Iz = 0), and Σ−b(Iz = −1). ### Charmed baryons Baryons that are composed of at least one charm quark are known as charmed baryons. ## Baryonic matter Baryonic [matter](https://www.newworldencyclopedia.org/entry/Matter "Matter") is matter composed mostly of baryons (by mass). It includes [atoms](https://www.newworldencyclopedia.org/entry/Atom "Atom") of all types, and thus includes nearly all types of matter that we may encounter or experience in everyday life, including the matter that constitutes human bodies. Non-baryonic matter, as implied by the name, is any sort of matter that is not primarily composed of baryons. It may include such ordinary matter as neutrinos or free [electrons](https://www.newworldencyclopedia.org/entry/Electron "Electron"), but it may also include exotic species of non-baryonic [dark matter](https://www.newworldencyclopedia.org/entry/Dark_matter "Dark matter"), such as supersymmetric particles, axions, or black holes. The distinction between baryonic and non-baryonic matter is important in cosmology, because Big Bang nucleosynthesis models set tight constraints on the amount of baryonic matter present in the early [universe](https://www.newworldencyclopedia.org/entry/Universe "Universe"). The very existence of baryons is also a significant issue in cosmology because current theory assumes that the Big Bang produced a state with equal amounts of baryons and anti-baryons. The process by which baryons came to outnumber their antiparticles is called baryogenesis. (This is distinct from a process by which [leptons](https://www.newworldencyclopedia.org/entry/Lepton "Lepton") account for the predominance of matter over antimatter, known as leptogenesis.) ## Baryogenesis Experiments are consistent with the number of quarks in the universe being a constant and, more specifically, the number of [baryons]() being a constant; in technical language, the total baryon number appears to be conserved. Within the prevailing [Standard Model](https://www.newworldencyclopedia.org/entry/Standard_Model "Standard Model") of particle physics, the number of baryons may change in multiples of three due to the action of sphalerons, although this is rare and has not been observed experimentally. Some grand unified theories of particle physics also predict that a single [proton](https://www.newworldencyclopedia.org/entry/Proton "Proton") can decay, changing the baryon number by one; however, this has not yet been observed experimentally. The excess of baryons over antibaryons in the present universe is thought to be due to non-conservation of baryon number in the very early universe, though this is not well understood. ## See also - [Antimatter](https://www.newworldencyclopedia.org/entry/Antimatter "Antimatter") - [Atom](https://www.newworldencyclopedia.org/entry/Atom "Atom") - [Dark matter](https://www.newworldencyclopedia.org/entry/Dark_matter "Dark matter") - [Fermion](https://www.newworldencyclopedia.org/entry/Fermion "Fermion") - [Hadron](https://www.newworldencyclopedia.org/entry/Hadron "Hadron") - [Lepton](https://www.newworldencyclopedia.org/entry/Lepton "Lepton") - [Matter](https://www.newworldencyclopedia.org/entry/Matter "Matter") - [Meson](https://www.newworldencyclopedia.org/entry/Meson "Meson") - [Neutron](https://www.newworldencyclopedia.org/entry/Neutron "Neutron") - [Particle physics](https://www.newworldencyclopedia.org/entry/Particle_physics "Particle physics") - [Proton](https://www.newworldencyclopedia.org/entry/Proton "Proton") - [Quark](https://www.newworldencyclopedia.org/entry/Quark "Quark") - [Standard Model](https://www.newworldencyclopedia.org/entry/Standard_Model "Standard Model") - [Subatomic particle](https://www.newworldencyclopedia.org/entry/Subatomic_particle "Subatomic particle") ## Notes 1. [↑](https://www.newworldencyclopedia.org/entry/Baryon#cite_ref-1) The Particle Adventure, [Hadrons: Baryons and Mesons.](http://www.particleadventure.org/frameless/hadrons.html) Retrieved September 10, 2008. 2. [↑](https://www.newworldencyclopedia.org/entry/Baryon#cite_ref-2) Hyper Physics, [Baryons.](http://hyperphysics.phy-astr.gsu.edu/Hbase/particles/hadron.html) Retrieved September 10, 2008. 3. [↑](https://www.newworldencyclopedia.org/entry/Baryon#cite_ref-PDGBaryonsymbols_3-0) M. Roos and C.G. Wohl, [Naming Scheme for Hadrons,](http://pdg.lbl.gov/2007/reviews/namingrpp.pdf) J. Phys G 33:1. Retrieved September 10, 2008. ## ReferencesISBN links support NWE through referral fees - Cottingham, W.N., and D.A. Greenwood. An Introduction to the Standard Model of Particle Physics, 2nd edition. Cambridge: Cambridge University Press, 2007. [ISBN 978-0521852494](https://www.amazon.com/gp/product/0521852498/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0521852498&linkCode=as2&tag=newworldencyc-20&linkId=83df4bed72539f2a52beb06a1d71be79) - Griffiths, David J. Introduction to Elementary Particles. New York: Wiley, 1987. [ISBN 0471603864](https://www.amazon.com/gp/product/0471603864/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0471603864&linkCode=as2&tag=newworldencyc-20&linkId=83df4bed72539f2a52beb06a1d71be79) - Halzen, Francis, and Alan D. Martin. Quarks and Leptons: An Introductory Course in Modern Particle Physics. New York: Wiley, 1984. [ISBN 0471887412](https://www.amazon.com/gp/product/0471887412/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0471887412&linkCode=as2&tag=newworldencyc-20&linkId=83df4bed72539f2a52beb06a1d71be79) - Martin, B. R. Nuclear and Particle Physics: An Introduction. Chichester: John Wiley, 2006. [ISBN 978-0470025321](https://www.amazon.com/gp/product/0470025328/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0470025328&linkCode=as2&tag=newworldencyc-20&linkId=83df4bed72539f2a52beb06a1d71be79) - Povh, Bogdan. Particles and Nuclei: An Introduction to the Physical Concepts. Berlin: Springer-Verlag, 1995. [ISBN 0387594396](https://www.amazon.com/gp/product/0387594396/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0387594396&linkCode=as2&tag=newworldencyc-20&linkId=83df4bed72539f2a52beb06a1d71be79) - Veltman, Martinus. Facts and Mysteries in Elementary Particle Physics. River Edge, NJ: World Scientific, 2003. [ISBN 981238149X](https://www.amazon.com/gp/product/981238149X/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=981238149X&linkCode=as2&tag=newworldencyc-20&linkId=83df4bed72539f2a52beb06a1d71be79) ## External links All links retrieved September 20, 2023. - [Baryons](http://hyperphysics.phy-astr.gsu.edu/Hbase/particles/hadron.html). - [Table of Baryons](http://hyperphysics.phy-astr.gsu.edu/hbase/particles/baryon.html#c1). - [The Review of Particle Physics](http://pdg.lbl.gov/). Particle Data Group. * \| Particles in physics \| \| \|---\|---\| \| [elementary particles](https://www.newworldencyclopedia.org/entry/Elementary_particle "Elementary particle") \| Elementary [fermions](https://www.newworldencyclopedia.org/entry/Fermion "Fermion"): [Quarks](https://www.newworldencyclopedia.org/entry/Quark "Quark"): u · d · s · c · b · t • [Leptons](https://www.newworldencyclopedia.org/entry/Lepton "Lepton"): [e](https://www.newworldencyclopedia.org/entry/Electron "Electron") · μ · τ · [νe · νμ · ντ](https://www.newworldencyclopedia.org/p/index.php?title=Neutrino&action=edit&redlink=1 "Neutrino (page does not exist)") Elementary [bosons](https://www.newworldencyclopedia.org/entry/Boson "Boson"): Gauge bosons: [γ](https://www.newworldencyclopedia.org/entry/Photon "Photon") · g · [W± · Z0](https://www.newworldencyclopedia.org/p/index.php?title=W_and_Z_bosons&action=edit&redlink=1 "W and Z bosons (page does not exist)") • Ghosts \| \| Composite particles \| [Hadrons](https://www.newworldencyclopedia.org/entry/Hadron "Hadron"): [Baryons]()(list)/Hyperons/Nucleons: [p](https://www.newworldencyclopedia.org/entry/Proton "Proton") · [n](https://www.newworldencyclopedia.org/entry/Neutron "Neutron") · Δ · Λ · Σ · Ξ · Ω · [Ξb](https://www.newworldencyclopedia.org/p/index.php?title=Cascade_B&action=edit&redlink=1 "Cascade B (page does not exist)") • [Mesons](https://www.newworldencyclopedia.org/entry/Meson "Meson")(list)/Quarkonia: π · K · ρ · J/ψ · Υ Other: [Atomic nucleus](https://www.newworldencyclopedia.org/entry/Atomic_nucleus "Atomic nucleus") • [Atoms](https://www.newworldencyclopedia.org/entry/Atom "Atom") • [Molecules](https://www.newworldencyclopedia.org/entry/Molecule "Molecule") • Positronium \| \| Hypothetical elementary particles \| Superpartners: Axino · Dilatino · Chargino · Gluino · Gravitino · Higgsino · Neutralino · Sfermion · Slepton · Squark Other: Axion · Dilaton · Goldstone boson · Graviton · Higgs boson · Tachyon · X · Y · W' · Z' \| \| Hypothetical composite particles \| Exotic hadrons: Exotic baryons: Pentaquark • Exotic mesons: Glueball · Tetraquark Other: Mesonic molecule** \| \| Quasiparticles \| Davydov soliton · Exciton · Magnon · Phonon · Plasmon · Polariton · Polaron \| ## Credits New World Encyclopedia writers and editors rewrote and completed the Wikipedia article in accordance with New World Encyclopedia [standards](https://www.newworldencyclopedia.org/entry/Help:Writers_Manual "Help:Writers Manual"). This article abides by terms of the [Creative Commons CC-by-sa 3.0 License](https://www.newworldencyclopedia.org/entry/New_World_Encyclopedia:Creative_Commons_CC-by-sa_3.0 "New World Encyclopedia:Creative Commons CC-by-sa 3.0") (CC-by-sa), which may be used and disseminated with proper attribution. Credit is due under the terms of this license that can reference both the New World Encyclopedia contributors and the selfless volunteer contributors of the Wikimedia Foundation. To cite this article [click here](https://www.newworldencyclopedia.org/entry/Special:CiteThisPage?page=Baryon&wpFormIdentifier=titleform) for a list of acceptable citing formats.The history of earlier contributions by wikipedians is accessible to researchers here: - [Baryon](http://en.wikipedia.org/w/index.php?title=Baryon&oldid=236246949) [history](http://en.wikipedia.org/w/index.php?title=Baryon&action=history) - [Baryon\_number](http://en.wikipedia.org/w/index.php?title=Baryon_number&oldid=230664144) [history](http://en.wikipedia.org/w/index.php?title=Baryon_number&action=history) - [Charmed\_baryon](http://en.wikipedia.org/w/index.php?title=Charmed_baryon&oldid=228720132) [history](http://en.wikipedia.org/w/index.php?title=Charmed_baryon&action=history) The history of this article since it was imported to New World Encyclopedia: - [History of "Baryon"](https://www.newworldencyclopedia.org/p/index.php?title=Baryon&action=history) Note: Some restrictions may apply to use of individual images which are separately licensed. Retrieved from <https://www.newworldencyclopedia.org/p/index.php?title=Baryon&oldid=1122623> [Categories](https://www.newworldencyclopedia.org/entry/Special:Categories "Special:Categories"): - [Physical sciences](https://www.newworldencyclopedia.org/entry/Category:Physical_sciences "Category:Physical sciences") - [Physics](https://www.newworldencyclopedia.org/entry/Category:Physics "Category:Physics") - [Particle physics](https://www.newworldencyclopedia.org/entry/Category:Particle_physics "Category:Particle physics") Hidden category: - [Pages using ISBN magic links](https://www.newworldencyclopedia.org/entry/Category:Pages_using_ISBN_magic_links "Category:Pages using ISBN magic links") [Privacy policy](https://www.newworldencyclopedia.org/entry/New_World_Encyclopedia:Privacy_policy "New World Encyclopedia:Privacy policy") [About New World Encyclopedia](https://www.newworldencyclopedia.org/entry/New_World_Encyclopedia:About "New World Encyclopedia:About") [Disclaimers](https://www.newworldencyclopedia.org/entry/New_World_Encyclopedia:General_disclaimer "New World Encyclopedia:General disclaimer") Content is available under [Creative Commons Attribution/Share-Alike License](https://www.newworldencyclopedia.org/entry/New%20World%20Encyclopedia:Creative_Commons_CC-by-sa_3.0); additional terms may apply. See [Terms of Use](https://www.newworldencyclopedia.org/entry/New_World_Encyclopedia:Terms_of_Use) for details. ![Copyright Logo](https://static.newworldencyclopedia.org/skins/common/images/Cc.logo.circle.png) [![Powered by MediaWiki](https://www.newworldencyclopedia.org/resources/assets/poweredby_mediawiki_88x31.png)](https://www.mediawiki.org/)
Readable Markdown	[![](https://www.newworldencyclopedia.org/d/images/thumb/9/92/Quark_structure_proton.svg/200px-Quark_structure_proton.svg.png)](https://www.newworldencyclopedia.org/entry/File:Quark_structure_proton.svg) A [proton](https://www.newworldencyclopedia.org/entry/Proton "Proton") is an example of a baryon. It is composed of 2 up quarks (u) and 1 down quark (d). The term baryon usually refers to a [subatomic particle](https://www.newworldencyclopedia.org/entry/Subatomic_particle "Subatomic particle") composed of three [quarks](https://www.newworldencyclopedia.org/entry/Quark "Quark").[\[1\]](https://www.newworldencyclopedia.org/entry/Baryon#cite_note-1) A more technical (and broader) definition is that it is a subatomic particle with a baryon number of 1. Baryons are a subset of [hadrons](https://www.newworldencyclopedia.org/entry/Hadron "Hadron"), (which are particles made of quarks), and they participate in the strong interaction. They are also a subset of [fermions](https://www.newworldencyclopedia.org/entry/Fermion "Fermion"). Well-known examples of baryons are [protons](https://www.newworldencyclopedia.org/entry/Proton "Proton") and [neutrons](https://www.newworldencyclopedia.org/entry/Neutron "Neutron"), which make up [atomic nuclei](https://www.newworldencyclopedia.org/entry/Atomic_nucleus "Atomic nucleus"), but many unstable baryons have been found as well. Some "exotic" baryons, known as pentaquarks, are thought to be composed of four quarks and one antiquark, but their existence is not generally accepted. Each baryon has a corresponding antiparticle, called an anti-baryon, in which quarks are replaced by their corresponding antiquarks. ## Etymology The term baryon is derived from the [Greek](https://www.newworldencyclopedia.org/entry/Greek_language "Greek language") word βαρύς (barys), meaning "heavy," because at the time of their naming it was believed that baryons were characterized by having greater mass than other particles. ## Basic properties Each baryon has an odd half-integer spin (such as 1 ⁄ 2 or 3 ⁄ 2), where "spin" refers to the angular momentum quantum number. Baryons are therefore classified as [fermions](https://www.newworldencyclopedia.org/entry/Fermion "Fermion"). They experience the strong nuclear force and are described by Fermi-Dirac statistics, which apply to all particles obeying the Pauli exclusion principle. This stands in contrast to [bosons](https://www.newworldencyclopedia.org/entry/Boson "Boson"), which do not obey the exclusion principle. Baryons, along with [mesons](https://www.newworldencyclopedia.org/entry/Meson "Meson"), are [hadrons](https://www.newworldencyclopedia.org/entry/Hadron "Hadron"), meaning they are particles composed of [quarks](https://www.newworldencyclopedia.org/entry/Quark "Quark"). Each quark has a baryon number of B = 1 ⁄ 3, and each antiquark has a baryon number of B = −1 ⁄ 3. The term baryon number is defined as: ![{\\displaystyle B={\\frac {N\_{q}-N\_{\\overline {q}}}{3}}}](https://wikimedia.org/api/rest_v1/media/math/render/svg/4353f4b7742621261045bfed6830d88ce839358b) where ![{\\displaystyle N\_{q}\\ }](https://wikimedia.org/api/rest_v1/media/math/render/svg/deedebab19fde96882032b92aeb46a667d963598) is the number of quarks, and ![{\\displaystyle N\_{\\overline {q}}}](https://wikimedia.org/api/rest_v1/media/math/render/svg/6f4711277ecf2dba9a848fbb60a4f02b30b55641) is the number of antiquarks. The term "baryon" is usually used for triquarks, that is, baryons made of three quarks. Thus, each baryon has a baryon number of 1 (B = 1 ⁄ 3 + 1 ⁄ 3 + 1 ⁄ 3 = 1). Some have suggested the existence of other, "exotic" baryons, such as pentaquarks—baryons made of four quarks and one antiquark (B = 1 ⁄ 3 + 1 ⁄ 3 + 1 ⁄ 3 + 1 ⁄ 3 − 1 ⁄ 3 = 1)—but their existence is not generally accepted. Theoretically, heptaquarks (5 quarks, 2 antiquarks), nonaquarks (6 quarks, 3 antiquarks), and so forth could also exist. Besides being associated with a spin number and a baryon number, each baryon has a quantum number known as strangeness. This quantity is equal to -1 times the number of strange quarks present in the baryon.[\[2\]](https://www.newworldencyclopedia.org/entry/Baryon#cite_note-2) ## Classification [![](https://www.newworldencyclopedia.org/d/images/thumb/f/f6/Baryon_decuplet.svg/200px-Baryon_decuplet.svg.png)](https://www.newworldencyclopedia.org/entry/File:Baryon_decuplet.svg) Combinations of three u, d or s-quarks with a total spin of 3/2 form the so-called baryon decuplet. [![](https://www.newworldencyclopedia.org/d/images/thumb/f/f6/Baryon_octet.svg/200px-Baryon_octet.svg.png)](https://www.newworldencyclopedia.org/entry/File:Baryon_octet.svg) The octet of light spin-1/2 baryons. Baryons are classified into groups according to their isospin values and [quark](https://www.newworldencyclopedia.org/entry/Quark "Quark") content. There are six groups of triquarks: - Nucleon (N) - Delta (Δ) - Lambda (Λ) - Sigma (Σ) - Xi (Ξ) - Omega (Ω) The rules for classification are defined by the Particle Data Group. The rules cover all the particles that can be made from three of each of the six quarks (up, down, strange, charm, bottom, top), although baryons made of top quarks are not expected to exist because of the top quark's short lifetime. (The rules do not cover pentaquarks.)[\[3\]](https://www.newworldencyclopedia.org/entry/Baryon#cite_note-PDGBaryonsymbols-3) According to these rules, the [u](https://www.newworldencyclopedia.org/p/index.php?title=Up_quark&action=edit&redlink=1 "Up quark (page does not exist)"), [d](https://www.newworldencyclopedia.org/p/index.php?title=Down_quark&action=edit&redlink=1 "Down quark (page does not exist)"), and [s](https://www.newworldencyclopedia.org/p/index.php?title=Strange_quark&action=edit&redlink=1 "Strange quark (page does not exist)") quarks are considered light, and the [c](https://www.newworldencyclopedia.org/p/index.php?title=Charm_quark&action=edit&redlink=1 "Charm quark (page does not exist)"), [b](https://www.newworldencyclopedia.org/p/index.php?title=Bottom_quark&action=edit&redlink=1 "Bottom quark (page does not exist)"), and [t](https://www.newworldencyclopedia.org/p/index.php?title=Top_quark&action=edit&redlink=1 "Top quark (page does not exist)") quarks are considered heavy. Based on the rules, the following classification system has been set up: - Baryons with three [u](https://www.newworldencyclopedia.org/p/index.php?title=Up_quark&action=edit&redlink=1 "Up quark (page does not exist)") and/or [d](https://www.newworldencyclopedia.org/p/index.php?title=Down_quark&action=edit&redlink=1 "Down quark (page does not exist)") quarks are grouped as [N](https://www.newworldencyclopedia.org/p/index.php?title=Nucleon&action=edit&redlink=1 "Nucleon (page does not exist)") (isospin 1 ⁄ 2 ) or [Δ](https://www.newworldencyclopedia.org/p/index.php?title=Delta_baryon&action=edit&redlink=1 "Delta baryon (page does not exist)") (isospin 3 ⁄ 2 ). - Baryons with two [u](https://www.newworldencyclopedia.org/p/index.php?title=Up_quark&action=edit&redlink=1 "Up quark (page does not exist)") and/or [d](https://www.newworldencyclopedia.org/p/index.php?title=Down_quark&action=edit&redlink=1 "Down quark (page does not exist)") quarks are grouped as [Λ](https://www.newworldencyclopedia.org/p/index.php?title=Lambda_baryon&action=edit&redlink=1 "Lambda baryon (page does not exist)") (isospin 0) or [Σ](https://www.newworldencyclopedia.org/p/index.php?title=Sigma_baryon&action=edit&redlink=1 "Sigma baryon (page does not exist)") (isospin 1). If the third quark is heavy, its identity is given by a subscript. - Baryons with one [u](https://www.newworldencyclopedia.org/p/index.php?title=Up_quark&action=edit&redlink=1 "Up quark (page does not exist)") or [d](https://www.newworldencyclopedia.org/p/index.php?title=Down_quark&action=edit&redlink=1 "Down quark (page does not exist)") quark are placed in the group [Ξ](https://www.newworldencyclopedia.org/p/index.php?title=Xi_baryon&action=edit&redlink=1 "Xi baryon (page does not exist)") (isospin 1 ⁄ 2 ). One or two subscripts are used if one or both of the remaining quarks are heavy. - Baryons with no [u](https://www.newworldencyclopedia.org/p/index.php?title=Up_quark&action=edit&redlink=1 "Up quark (page does not exist)") or [d](https://www.newworldencyclopedia.org/p/index.php?title=Down_quark&action=edit&redlink=1 "Down quark (page does not exist)") quarks are placed in the group [Ω](https://www.newworldencyclopedia.org/p/index.php?title=Omega_baryon&action=edit&redlink=1 "Omega baryon (page does not exist)") (isospin 0), and subscripts indicate any heavy quark content. - Some baryons decay strongly, in which case their masses are shown as part of their names. For example, Sigmas (Σ) and Omegas (Ω) do not decay strongly, but Deltas (Δ(1232)), and charmed Xis (Ξ\+c(2645)) do. Given that quarks carry charge, knowledge of the charge of a particle indirectly gives the quark content. For example, the rules say that the Σb contains a bottom and some combination of two up and/or down quarks. A Σ0b must be one up quark (Q=2 ⁄ 3), one down quark (Q=−1 ⁄ 3), and one bottom quark (Q=−1 ⁄ 3) to have the correct charge (Q=0). The number of baryons within one group (excluding resonances) is given by the number of isospin projections possible (2 × isospin + 1). For example, there are four Δ's, corresponding to the four isospin projections of the isospin value I = 3 ⁄ 2: Δ\++ (Iz = 3 ⁄ 2), Δ\+(Iz = 1 ⁄ 2), Δ0(Iz = −1 ⁄ 2), and Δ−(Iz = −3 ⁄ 2). Another example would be the three Σb's, corresponding to the three isospin projections of the isospin value I = 1: Σ\+b (Iz = 1), Σ0b(Iz = 0), and Σ−b(Iz = −1). ### Charmed baryons Baryons that are composed of at least one charm quark are known as charmed baryons. ## Baryonic matter Baryonic [matter](https://www.newworldencyclopedia.org/entry/Matter "Matter") is matter composed mostly of baryons (by mass). It includes [atoms](https://www.newworldencyclopedia.org/entry/Atom "Atom") of all types, and thus includes nearly all types of matter that we may encounter or experience in everyday life, including the matter that constitutes human bodies. Non-baryonic matter, as implied by the name, is any sort of matter that is not primarily composed of baryons. It may include such ordinary matter as neutrinos or free [electrons](https://www.newworldencyclopedia.org/entry/Electron "Electron"), but it may also include exotic species of non-baryonic [dark matter](https://www.newworldencyclopedia.org/entry/Dark_matter "Dark matter"), such as supersymmetric particles, axions, or black holes. The distinction between baryonic and non-baryonic matter is important in cosmology, because Big Bang nucleosynthesis models set tight constraints on the amount of baryonic matter present in the early [universe](https://www.newworldencyclopedia.org/entry/Universe "Universe"). The very existence of baryons is also a significant issue in cosmology because current theory assumes that the Big Bang produced a state with equal amounts of baryons and anti-baryons. The process by which baryons came to outnumber their antiparticles is called baryogenesis. (This is distinct from a process by which [leptons](https://www.newworldencyclopedia.org/entry/Lepton "Lepton") account for the predominance of matter over antimatter, known as leptogenesis.) ## Baryogenesis Experiments are consistent with the number of quarks in the universe being a constant and, more specifically, the number of [baryons]() being a constant; in technical language, the total baryon number appears to be conserved. Within the prevailing [Standard Model](https://www.newworldencyclopedia.org/entry/Standard_Model "Standard Model") of particle physics, the number of baryons may change in multiples of three due to the action of sphalerons, although this is rare and has not been observed experimentally. Some grand unified theories of particle physics also predict that a single [proton](https://www.newworldencyclopedia.org/entry/Proton "Proton") can decay, changing the baryon number by one; however, this has not yet been observed experimentally. The excess of baryons over antibaryons in the present universe is thought to be due to non-conservation of baryon number in the very early universe, though this is not well understood. ## See also - [Antimatter](https://www.newworldencyclopedia.org/entry/Antimatter "Antimatter") - [Atom](https://www.newworldencyclopedia.org/entry/Atom "Atom") - [Dark matter](https://www.newworldencyclopedia.org/entry/Dark_matter "Dark matter") - [Fermion](https://www.newworldencyclopedia.org/entry/Fermion "Fermion") - [Hadron](https://www.newworldencyclopedia.org/entry/Hadron "Hadron") - [Lepton](https://www.newworldencyclopedia.org/entry/Lepton "Lepton") - [Matter](https://www.newworldencyclopedia.org/entry/Matter "Matter") - [Meson](https://www.newworldencyclopedia.org/entry/Meson "Meson") - [Neutron](https://www.newworldencyclopedia.org/entry/Neutron "Neutron") - [Particle physics](https://www.newworldencyclopedia.org/entry/Particle_physics "Particle physics") - [Proton](https://www.newworldencyclopedia.org/entry/Proton "Proton") - [Quark](https://www.newworldencyclopedia.org/entry/Quark "Quark") - [Standard Model](https://www.newworldencyclopedia.org/entry/Standard_Model "Standard Model") - [Subatomic particle](https://www.newworldencyclopedia.org/entry/Subatomic_particle "Subatomic particle") ## Notes 1. [↑](https://www.newworldencyclopedia.org/entry/Baryon#cite_ref-1) The Particle Adventure, [Hadrons: Baryons and Mesons.](http://www.particleadventure.org/frameless/hadrons.html) Retrieved September 10, 2008. 2. [↑](https://www.newworldencyclopedia.org/entry/Baryon#cite_ref-2) Hyper Physics, [Baryons.](http://hyperphysics.phy-astr.gsu.edu/Hbase/particles/hadron.html) Retrieved September 10, 2008. 3. [↑](https://www.newworldencyclopedia.org/entry/Baryon#cite_ref-PDGBaryonsymbols_3-0) M. Roos and C.G. Wohl, [Naming Scheme for Hadrons,](http://pdg.lbl.gov/2007/reviews/namingrpp.pdf) J. Phys G 33:1. Retrieved September 10, 2008. ## ReferencesISBN links support NWE through referral fees - Cottingham, W.N., and D.A. Greenwood. An Introduction to the Standard Model of Particle Physics, 2nd edition. Cambridge: Cambridge University Press, 2007. [ISBN 978-0521852494](https://www.amazon.com/gp/product/0521852498/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0521852498&linkCode=as2&tag=newworldencyc-20&linkId=83df4bed72539f2a52beb06a1d71be79) - Griffiths, David J. Introduction to Elementary Particles. New York: Wiley, 1987. [ISBN 0471603864](https://www.amazon.com/gp/product/0471603864/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0471603864&linkCode=as2&tag=newworldencyc-20&linkId=83df4bed72539f2a52beb06a1d71be79) - Halzen, Francis, and Alan D. Martin. Quarks and Leptons: An Introductory Course in Modern Particle Physics. New York: Wiley, 1984. [ISBN 0471887412](https://www.amazon.com/gp/product/0471887412/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0471887412&linkCode=as2&tag=newworldencyc-20&linkId=83df4bed72539f2a52beb06a1d71be79) - Martin, B. R. Nuclear and Particle Physics: An Introduction. Chichester: John Wiley, 2006. [ISBN 978-0470025321](https://www.amazon.com/gp/product/0470025328/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0470025328&linkCode=as2&tag=newworldencyc-20&linkId=83df4bed72539f2a52beb06a1d71be79) - Povh, Bogdan. Particles and Nuclei: An Introduction to the Physical Concepts. Berlin: Springer-Verlag, 1995. [ISBN 0387594396](https://www.amazon.com/gp/product/0387594396/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=0387594396&linkCode=as2&tag=newworldencyc-20&linkId=83df4bed72539f2a52beb06a1d71be79) - Veltman, Martinus. Facts and Mysteries in Elementary Particle Physics. River Edge, NJ: World Scientific, 2003. [ISBN 981238149X](https://www.amazon.com/gp/product/981238149X/ref=as_li_tl?ie=UTF8&camp=1789&creative=9325&creativeASIN=981238149X&linkCode=as2&tag=newworldencyc-20&linkId=83df4bed72539f2a52beb06a1d71be79) ## External links All links retrieved September 20, 2023. - [Baryons](http://hyperphysics.phy-astr.gsu.edu/Hbase/particles/hadron.html). - [Table of Baryons](http://hyperphysics.phy-astr.gsu.edu/hbase/particles/baryon.html#c1). - [The Review of Particle Physics](http://pdg.lbl.gov/). Particle Data Group. * \| Particles in physics \| \| \|---\|---\| \| [elementary particles](https://www.newworldencyclopedia.org/entry/Elementary_particle "Elementary particle") \| Elementary [fermions](https://www.newworldencyclopedia.org/entry/Fermion "Fermion"): [Quarks](https://www.newworldencyclopedia.org/entry/Quark "Quark"): u · d · s · c · b · t • [Leptons](https://www.newworldencyclopedia.org/entry/Lepton "Lepton"): [e](https://www.newworldencyclopedia.org/entry/Electron "Electron") · μ · τ · [νe · νμ · ντ](https://www.newworldencyclopedia.org/p/index.php?title=Neutrino&action=edit&redlink=1 "Neutrino (page does not exist)") Elementary [bosons](https://www.newworldencyclopedia.org/entry/Boson "Boson"): Gauge bosons: [γ](https://www.newworldencyclopedia.org/entry/Photon "Photon") · g · [W± · Z0](https://www.newworldencyclopedia.org/p/index.php?title=W_and_Z_bosons&action=edit&redlink=1 "W and Z bosons (page does not exist)") • Ghosts \| \| Composite particles \| [Hadrons](https://www.newworldencyclopedia.org/entry/Hadron "Hadron"): [Baryons]()(list)/Hyperons/Nucleons: [p](https://www.newworldencyclopedia.org/entry/Proton "Proton") · [n](https://www.newworldencyclopedia.org/entry/Neutron "Neutron") · Δ · Λ · Σ · Ξ · Ω · [Ξb](https://www.newworldencyclopedia.org/p/index.php?title=Cascade_B&action=edit&redlink=1 "Cascade B (page does not exist)") • [Mesons](https://www.newworldencyclopedia.org/entry/Meson "Meson")(list)/Quarkonia: π · K · ρ · J/ψ · Υ Other: [Atomic nucleus](https://www.newworldencyclopedia.org/entry/Atomic_nucleus "Atomic nucleus") • [Atoms](https://www.newworldencyclopedia.org/entry/Atom "Atom") • [Molecules](https://www.newworldencyclopedia.org/entry/Molecule "Molecule") • Positronium \| \| Hypothetical elementary particles \| Superpartners: Axino · Dilatino · Chargino · Gluino · Gravitino · Higgsino · Neutralino · Sfermion · Slepton · Squark Other: Axion · Dilaton · Goldstone boson · Graviton · Higgs boson · Tachyon · X · Y · W' · Z' \| \| Hypothetical composite particles \| Exotic hadrons: Exotic baryons: Pentaquark • Exotic mesons: Glueball · Tetraquark Other: Mesonic molecule** \| \| Quasiparticles \| Davydov soliton · Exciton · Magnon · Phonon · Plasmon · Polariton · Polaron \| ## Credits New World Encyclopedia writers and editors rewrote and completed the Wikipedia article in accordance with New World Encyclopedia [standards](https://www.newworldencyclopedia.org/entry/Help:Writers_Manual "Help:Writers Manual"). This article abides by terms of the [Creative Commons CC-by-sa 3.0 License](https://www.newworldencyclopedia.org/entry/New_World_Encyclopedia:Creative_Commons_CC-by-sa_3.0 "New World Encyclopedia:Creative Commons CC-by-sa 3.0") (CC-by-sa), which may be used and disseminated with proper attribution. Credit is due under the terms of this license that can reference both the New World Encyclopedia contributors and the selfless volunteer contributors of the Wikimedia Foundation. To cite this article [click here](https://www.newworldencyclopedia.org/entry/Special:CiteThisPage?page=Baryon&wpFormIdentifier=titleform) for a list of acceptable citing formats.The history of earlier contributions by wikipedians is accessible to researchers here: - [Baryon](http://en.wikipedia.org/w/index.php?title=Baryon&oldid=236246949) [history](http://en.wikipedia.org/w/index.php?title=Baryon&action=history) - [Baryon\_number](http://en.wikipedia.org/w/index.php?title=Baryon_number&oldid=230664144) [history](http://en.wikipedia.org/w/index.php?title=Baryon_number&action=history) - [Charmed\_baryon](http://en.wikipedia.org/w/index.php?title=Charmed_baryon&oldid=228720132) [history](http://en.wikipedia.org/w/index.php?title=Charmed_baryon&action=history) The history of this article since it was imported to New World Encyclopedia: - [History of "Baryon"](https://www.newworldencyclopedia.org/p/index.php?title=Baryon&action=history) Note: Some restrictions may apply to use of individual images which are separately licensed.
Shard	124 (laksa)
Root Hash	5774774004535495924
Unparsed URL	org,newworldencyclopedia!www,/entry/Baryon s443