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{{Short description|List of particles in matter including fermions and bosons}}This is a list of known and hypothesized particles.

Standard Model elementary particles

{{hatnote|See Standard Model for the current consensus theory of these particles.}}Elementary particles are particles with no measurable internal structure; that is, it is unknown whether they are composed of other particles.BOOK , They are the fundamental objects of quantum field theory. Many families and sub-families of elementary particles exist. Elementary particles are classified according to their spin. Fermions have half-integer spin while bosons have integer spin. All the particles of the Standard Model have been experimentally observed, including the Higgs boson in 2012.JOURNAL, Khachatryan, V., etal, CMS Collaboration, 2012, Observation of a new boson at a mass of 125 GeV with the CMS experiment at the LHC, Physics Letters B, 716, 2012, 30–61, 1207.7235, 2012PhLB..716...30C, 10.1016/j.physletb.2012.08.021, JOURNAL, Abajyan, T., ATLAS Collaboration, etal, Observation of a new particle in the search for the Standard Model Higgs boson with the ATLAS detector at the LHC, Physics Letters B, 716, 2012, 1–29, 2012, 1207.7214, 2012PhLB..716....1A, 10.1016/j.physletb.2012.08.020, 119169617, Many other hypothetical elementary particles, such as the graviton, have been proposed, but not observed experimentally.

Fermions

Fermions are one of the two fundamental classes of particles, the other being bosons. Fermion particles are described by Fermi–Dirac statistics and have quantum numbers described by the Pauli exclusion principle. They include the quarks and leptons, as well as any composite particles consisting of an odd number of these, such as all baryons and many atoms and nuclei.Fermions have half-integer spin; for all known elementary fermions this is {{frac|1|2}}. All known fermions except neutrinos, are also Dirac fermions; that is, each known fermion has its own distinct antiparticle. It is not known whether the neutrino is a Dirac fermion or a Majorana fermion.ARXIV, 1012.4469, Kayser, Boris, Two Questions About Neutrinos, hep-ph, 2010, Fermions are the basic building blocks of all matter. They are classified according to whether they interact via the strong interaction or not. In the Standard Model, there are 12 types of elementary fermions: six quarks and six leptons.

Quarks

Quarks are the fundamental constituents of hadrons and interact via the strong force. Quarks are the only known carriers of fractional charge, but because they combine in groups of three quarks (baryons) or in pairs of one quark and one antiquark (mesons), only integer charge is observed in nature. Their respective antiparticles are the antiquarks, which are identical except that they carry the opposite electric charge (for example the up quark carries charge +{{frac|2|3}}, while the up antiquark carries charge −{{frac|2|3}}), color charge, and baryon number. There are six flavors of quarks; the three positively charged quarks are called "up-type quarks" while the three negatively charged quarks are called "down-type quarks".{|class="wikitable sortable" style="margin:1em auto; text-align:center"|+Quarks! Generation !! Name !! Symbol !! Antiparticle !! Spin !! Charge(e) !! data-sort-type="number"|Mass (MeV/c2) JOURNAL, Review of Particle Physics, Particle Data Group, Chinese Physics C, 40, 10, 100001, 2016, 10.1088/1674-1137/40/10/100001, 2016ChPhC..40j0001P, 1983/c6dc3926-daee-4d0e-9149-5ff3a8120574, 125766528,weblink free,

1	Up quark>up	u	{{Subatomic particle|up antiquark}}	{{frac	2}}	+{{frac	3}}	{{val	0.6|0.4}}

Down quark>down	d	{{Subatomic particle|down antiquark}}	{{frac	2}}	−{{frac	3}}	{{val	0.5|0.4}}

2	Charm quark>charm	c	{{Subatomic particle|charm antiquark}}	{{frac	2}}	+{{frac	3}}	{{val	30}}

Strange quark>strange	s	{{Subatomic particle|strange antiquark}}	{{frac	2}}	−{{frac	3}}	{{val	8|4}}

3	Top quark>top	t	{{Subatomic particle|top antiquark}}	{{frac	2}}	+{{frac	3}}	{{val	600}}

Bottom quark>bottom	b	{{Subatomic particle|bottom antiquark}}	{{frac	2}}	−{{frac	3}}	{{val	40|30}}

Leptons

Leptons do not interact via the strong interaction. Their respective antiparticles are the antileptons, which are identical, except that they carry the opposite electric charge and lepton number. The antiparticle of an electron is an antielectron, which is almost always called a "positron" for historical reasons. There are six leptons in total; the three charged leptons are called "electron-like leptons", while the neutral leptons are called "neutrinos". Neutrinos are known to oscillate, so that neutrinos of definite flavor do not have definite mass: Instead, they exist in a superposition of mass eigenstates. The hypothetical heavy right-handed neutrino, called a "sterile neutrino", has been omitted.{|class="wikitable sortable" style="margin:1em auto; text-align:center"|+Leptons! Generation !! Name !! Symbol !! Antiparticle !! Spin !! Charge(e) !! Mass(MeV/c²)

1	electron >	electron}}	{{Subatomic particle|positron}}	{{sfrac	2 }}	−1	0.511{{refn|group=note|A precise value of the electron mass is {{physconst|mec2_MeV|unit=no|after= {{val|u=MeV/c2}}.}}}}

< 0.0000022 }}

electron neutrino >	{{Subatomic particle		{{Subatomic particle|electron antineutrino}}}}	{{sfrac	2 }}	0	{{nobr|

2	muon >	{{Subatomic particle		{{Subatomic particle|antimuon}}}}	{{sfrac	2 }}	−1	105.7{{refn|group=note|A precise value of the muon mass is {{physconst|mmuc2_MeV|unit=no|after= {{val|u=MeV/c2}}.}}}}

< 0.170 }}

muon neutrino >	{{Subatomic particle		{{Subatomic particle|muon antineutrino}}}}	{{sfrac	2 }}	0	{{nobr|

3	Tau (particle)>tau	{{math	tau}}}}	{{math	antitau}}}}	{{sfrac	2 }}	−1	{{val	0.12}}

< 15.5 }}

tau neutrino >	{{Subatomic particle		{{Subatomic particle|tau antineutrino}}}}	{{sfrac	2 }}	0	{{nobr|

{{reflist|group=note}}

Bosons

Bosons are one of the two fundamental particles having integral spinclasses of particles, the other being fermions. Bosons are characterized by Bose–Einstein statistics and all have integer spins. Bosons may be either elementary, like photons and gluons, or composite, like mesons.According to the Standard Model, the elementary bosons are:{| class="wikitable sortable" style="margin:1em auto; align: center; text-align: center;"! Name !! Symbol !! Antiparticle !! Spin !! Charge (e) !! Mass (GeV/c2) !! Interaction mediated !!Observed

photon >	γ}}	self	1	0	0	electromagnetism	{{yes}}

W and Z bosons>W boson	{{Subatomic particle		W Boson+}}	1	±1	{{val	0.015}}	weak interaction	{{yes}}

W and Z bosons>Z boson	{{Subatomic particle					91.1875		weak interaction >| {{yes}}

gluon >	Gluon}}	self	1	0	0		strong interaction >| {{yes}}

Higgs boson >	Higgs boson}}	self	0	0	{{val	0.24}}	mass	{{yes}}

The Higgs boson is postulated by the electroweak theory primarily to explain the origin of particle masses. In a process known as the "Higgs mechanism", the Higgs boson and the other gauge bosons in the Standard Model acquire mass via spontaneous symmetry breaking of the SU(2) gauge symmetry. The Minimal Supersymmetric Standard Model (MSSM) predicts several Higgs bosons. On 4 July 2012, the discovery of a new particle with a mass between {{val|125|and|127|u=GeV/c2}} was announced; physicists suspected that it was the Higgs boson. Since then, the particle has been shown to behave, interact, and decay in many of the ways predicted for Higgs particles by the Standard Model, as well as having even parity and zero spin, two fundamental attributes of a Higgs boson. This also means it is the first elementary scalar particle discovered in nature.Elementary bosons responsible for the four fundamental forces of nature are called force particles (gauge bosons). Strong interaction is mediated by the gluon, weak interaction is mediated by the W and Z bosons.

Hypothetical particles

Graviton {| class"wikitable sortable" style"margin:1em auto; align: center; text-align: center;"

! Name !! Symbol !! Antiparticle !! Spin !! Charge (e) !! Mass (GeV/c2) !! Interaction mediated !!Observed

graviton >						gravitation >| {{no}}

The graviton is a hypothetical particle that has been included in some extensions to the standard model to mediate the gravitational force. It is in a peculiar category between known and hypothetical particles: As an unobserved particle that is not predicted by, nor required for the Standard Model, it belongs in the table of hypothetical particles, below. But gravitational force itself is a certainty, and expressing that known force in the framework of a quantum field theory requires a boson to mediate it.If it exists, the graviton is expected to be massless because the gravitational force has a very long range, and appears to propagate at the speed of light. The graviton must be a spin-2 boson because the source of gravitation is the stress–energy tensor, a second-order tensor (compared with electromagnetism's spin-1 photon, the source of which is the four-current, a first-order tensor). Additionally, it can be shown that any massless spin-2 field would give rise to a force indistinguishable from gravitation, because a massless spin-2 field would couple to the stress–energy tensor in the same way that gravitational interactions do. This result suggests that, if a massless spin-2 particle is discovered, it must be the graviton.For a comparison of the geometric derivation and the (non-geometric) spin-2 field derivation of general relativity, refer to box 18.1 (and also 17.2.5) of BOOK ,

Particles predicted by supersymmetric theories

Supersymmetric theories predict the existence of more particles, none of which have been confirmed experimentally.{|class="wikitable" style="margin:1em auto;"|+Superpartners (Sparticles)! Superpartner !! Spin !!width="500"| Notes !! superpartner of:

chargino >	{{sfrac	2}} }}	The charginos are quantum superposition	of the superpartners of charged Standard Model bosons: charged Higgs boson and {{nobr>W boson}}.The Minimal Supersymmetric Standard Model	predicts two pairs of charginos. >| charged bosons

gluino >	{{sfrac	2}} }}	Eight gluons and eight gluinos.	gluon

gravitino >	{{sfrac	2}} }}	Predicted by supergravity (Supergravity	). The graviton is hypothetical, too – see previous table. >| graviton

Higgsino >	{{sfrac	 2}} }}	For supersymmetry there is a need for several Higgs bosons, neutral and charged, according with their superpartners.	Higgs boson

neutralino >	{{sfrac	2}} }}	The neutralinos are quantum superposition	of the superpartners of neutral Standard Model bosons: neutral Higgs boson, Z boson and photon.The lightest neutralino is a leading candidate for dark matter.The Minimal Supersymmetric Standard Model>MSSM predicts four neutralinos.	neutral bosons

photino >	{{sfrac	2}} }}	Mixing with zino and neutral Higgsinos for neutralinos.	photon

sleptons >	0}}	The superpartners of the leptons (electron, muon, tau) and the neutrinos.	leptons

sneutrino >	0}}	Introduced by many extensions of the Standard Supermodel, and may be needed to explain the LSND results.A special role has the sterile sneutrino, the supersymmetric counterpart of the hypothetical right-handed neutrino, called the "sterile neutrino".	neutrino

squarks >	0}}	The stop squark (superpartner of the top quark) is thought to have a low mass and is often the subject of experimental searches.	quarks

gaugino>wino, zino	{{center	 1 			W and Z bosons>W{{sup	0}} bosons

Just as the photon, Z boson and W{{sup|±}} bosons are superpositions of the B{{sup|0}}, W{{sup|0}}, W{{sup|1}}, and W{{sup|2}} fields, the photino, zino, and wino{{sup|±}} are superpositions of the bino{{sup|0}}, wino{{sup|0}}, wino{{sup|1}}, and wino{{sup|2}}. No matter if one uses the original gauginos or this superpositions as a basis, the only predicted physical particles are neutralinos and charginos as a superposition of them together with the Higgsinos.

Other hypothetical bosons and fermions

Other theories predict the existence of additional elementary bosons and fermions, with some theories also postulating additional superpartners for these particles: