:''This list is of all known and predicted scalar, pseudoscalar and

vector Vector most often refers to: *Euclidean vector, a quantity with a magnitude and a direction *Vector (epidemiology), an agent that carries and transmits an infectious pathogen into another living organism Vector may also refer to: Mathematic ...

meson In particle physics, a meson ( or ) is a type of hadronic subatomic particle composed of an equal number of quarks and antiquarks, usually one of each, bound together by the strong interaction. Because mesons are composed of quark subparticles, ...

s. See list of particles for a more detailed list of particles found in

particle physics Particle physics or high energy physics is the study of fundamental particles and forces that constitute matter and radiation. The fundamental particles in the universe are classified in the Standard Model as fermions (matter particles) an ...

.'' This article contains a list of mesons, unstable

subatomic particle In physical sciences, a subatomic particle is a particle that composes an atom. According to the Standard Model of particle physics, a subatomic particle can be either a composite particle, which is composed of other particles (for example, a p ...

s composed of one

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

and one

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

. They are part of the

hadron In particle physics, a hadron (; grc, ἁδρός, hadrós; "stout, thick") is a composite subatomic particle made of two or more quarks held together by the strong interaction. They are analogous to molecules that are held together by the ...

particle family—particles made of quarks. The other members of the hadron family are the

baryon In particle physics, a baryon is a type of composite subatomic particle which contains an odd number of valence quarks (at least 3). Baryons belong to the hadron family of particles; hadrons are composed of quarks. Baryons are also classifie ...

s—subatomic particles composed of three quarks. The main difference between

s and baryons is that mesons have integer

spin Spin or spinning most often refers to: * Spinning (textiles), the creation of yarn or thread by twisting fibers together, traditionally by hand spinning * Spin, the rotation of an object around a central axis * Spin (propaganda), an intentionally ...

(thus are

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

s) while baryons are

fermion In particle physics, a fermion is a particle that follows Fermi–Dirac statistics. Generally, it has a half-odd-integer spin: spin , spin , etc. In addition, these particles obey the Pauli exclusion principle. Fermions include all quarks and ...

s (half-integer spin). Because mesons are bosons, the

Pauli exclusion principle In quantum mechanics, the Pauli exclusion principle states that two or more identical particles with half-integer spins (i.e. fermions) cannot occupy the same quantum state within a quantum system simultaneously. This principle was formula ...

does not apply to them. Because of this, they can act as force mediating particles on short distances, and thus play a part in processes such as the nuclear interaction. Since mesons are composed of quarks, they participate in both the

weak Weak may refer to: Songs * "Weak" (AJR song), 2016 * "Weak" (Melanie C song), 2011 * "Weak" (SWV song), 1993 * "Weak" (Skunk Anansie song), 1995 * "Weak", a song by Seether from '' Seether: 2002-2013'' Television episodes * "Weak" (''Fear t ...

and

strong interaction The strong interaction or strong force is a fundamental interaction that confines quarks into proton, neutron, and other hadron particles. The strong interaction also binds neutrons and protons to create atomic nuclei, where it is called th ...

s. Mesons with net

electric charge Electric charge is the physical property of matter that causes charged matter to experience a force when placed in an electromagnetic field. Electric charge can be ''positive'' or ''negative'' (commonly carried by protons and electrons res ...

also participate in the

electromagnetic interaction In physics, electromagnetism is an interaction that occurs between particles with electric charge. It is the second-strongest of the four fundamental interactions, after the strong force, and it is the dominant force in the interactions o ...

. They are classified according to their quark content,

total angular momentum In quantum mechanics, the total angular momentum quantum number parametrises the total angular momentum of a given particle, by combining its orbital angular momentum and its intrinsic angular momentum (i.e., its spin). If s is the particle's sp ...

parity Parity may refer to: * Parity (computing) ** Parity bit in computing, sets the parity of data for the purpose of error detection ** Parity flag in computing, indicates if the number of set bits is odd or even in the binary representation of the ...

, and various other properties such as

C-parity In physics, the C parity or charge parity is a multiplicative quantum number of some particles that describes their behavior under the symmetry operation of charge conjugation. Charge conjugation changes the sign of all quantum charges (that is, ...

and G-parity. While no meson is stable, those of lower

mass Mass is an intrinsic property of a body. It was traditionally believed to be related to the quantity of matter in a physical body, until the discovery of the atom and particle physics. It was found that different atoms and different ele ...

are nonetheless more stable than the most massive mesons, and are easier to observe and study in

particle accelerator A particle accelerator is a machine that uses electromagnetic fields to propel charged particles to very high speeds and energies, and to contain them in well-defined beams. Large accelerators are used for fundamental research in particle ...

s or in

cosmic ray Cosmic rays are high-energy particles or clusters of particles (primarily represented by protons or atomic nuclei) that move through space at nearly the speed of light. They originate from the Sun, from outside of the Solar System in our own ...

experiments. They are also typically less massive than baryons, meaning that they are more easily produced in experiments, and will exhibit higher-energy phenomena sooner than baryons would. For example, the charm quark was first seen in the J/Psi meson () in 1974, and the bottom quark in the

upsilon meson The Upsilon meson () is a quarkonium state (i.e. flavourless meson) formed from a bottom quark and its antiparticle. It was discovered by the E288 experiment team, headed by Leon Lederman, at Fermilab in 1977, and was the first particle containi ...

() in 1977. The top quark (the last and heaviest quark to be discovered to date) was first observed at

Fermilab Fermi National Accelerator Laboratory (Fermilab), located just outside Batavia, Illinois, near Chicago, is a United States Department of Energy national laboratory specializing in high-energy particle physics. Since 2007, Fermilab has been oper ...

in 1995. Each meson has a corresponding

antiparticle In particle physics, every type of particle is associated with an antiparticle with the same mass but with opposite physical charges (such as electric charge). For example, the antiparticle of the electron is the positron (also known as an antie ...

(antimeson) where quarks are replaced by their corresponding antiquarks and vice versa. For example, a positive

pion In particle physics, a pion (or a pi meson, denoted with the Greek letter pi: ) is any of three subatomic particles: , , and . Each pion consists of a quark and an antiquark and is therefore a meson. Pions are the lightest mesons and, more gene ...

() is made of one up quark and one down antiquark; and its corresponding antiparticle, the negative pion (), is made of one up antiquark and one down quark. Although tetraquarks with two quarks and two antiquarks can be considered mesons they are not listed here. The symbols encountered in these lists are: I (''

isospin In nuclear physics and particle physics, isospin (''I'') is a quantum number related to the up- and down quark content of the particle. More specifically, isospin symmetry is a subset of the flavour symmetry seen more broadly in the interactions ...

''), J (''

''), P (''

''), C (''

''), G ('' G-parity''), u (''

up quark The up quark or u quark (symbol: u) is the lightest of all quarks, a type of elementary particle, and a significant constituent of matter. It, along with the down quark, forms the neutrons (one up quark, two down quarks) and protons (two up quark ...

''), d (''

down quark The down quark or d quark (symbol: d) is the second-lightest of all quarks, a type of elementary particle, and a major constituent of matter. Together with the up quark, it forms the neutrons (one up quark, two down quarks) and protons (two up ...

''), s (''

strange quark The strange quark or s quark (from its symbol, s) is the third lightest of all quarks, a type of elementary particle. Strange quarks are found in subatomic particles called hadrons. Examples of hadrons containing strange quarks include kaons ( ...

''), c (''

charm quark The charm quark, charmed quark or c quark (from its symbol, c) is the third-most massive of all quarks, a type of elementary particle. Charm quarks are found in hadrons, which are subatomic particles made of quarks. Examples of hadrons containin ...

''), b (''

bottom quark The bottom quark or b quark, also known as the beauty quark, is a third-generation heavy quark with a charge of − ''e''. All quarks are described in a similar way by electroweak and quantum chromodynamics, but the bottom quark has exce ...

''), Q (''

charge Charge or charged may refer to: Arts, entertainment, and media Films * '' Charge, Zero Emissions/Maximum Speed'', a 2011 documentary Music * ''Charge'' (David Ford album) * ''Charge'' (Machel Montano album) * ''Charge!!'', an album by The Aqu ...

''), B (''

baryon number In particle physics, the baryon number is a strictly conserved additive quantum number of a system. It is defined as ::B = \frac\left(n_\text - n_\bar\right), where ''n''q is the number of quarks, and ''n'' is the number of antiquarks. Baryo ...

''), S (''

strangeness In particle physics, strangeness ("''S''") is a property of particles, expressed as a quantum number, for describing decay of particles in strong and electromagnetic interactions which occur in a short period of time. The strangeness of a parti ...

''), C (''

charm Charm may refer to: Social science * Charisma, a person or thing's pronounced ability to attract others * Superficial charm, flattery, telling people what they want to hear Science and technology * Charm quark, a type of elementary particle * Ch ...

''), and B′ (''

bottomness In physics, bottomness (symbol ''B''′ using a prime as plain ''B'' is used already for baryon number) or beauty is a flavour quantum number reflecting the difference between the number of bottom antiquarks (''n'') and the number of botto ...

''), as well as a wide array of subatomic particles (hover mouse for name).

Summary table

Because this table was initially derived from published results and many of those results were preliminary, as many as 64 of the mesons in the following table may not exist or have the wrong mass or quantum numbers. Mesons named with the letter "f" are ''scalar mesons'' (as opposed to a pseudo-scalar meson), and mesons named with the letter "a" are axial-vector mesons (as opposed to an ordinary vector meson) a.k.a. an isoscalar vector meson, while the letters "b" and "h" refer to axial-vector mesons with positive parity, negative C-parity, and quantum numbers I^G of 1⁺ and 0⁻ respectively. The, "f", "a", "b" and "h" mesons are not listed in the tables below and their internal structure and quark content is a matter of ongoing investigation. The particle described in the table above as f₀(500) has historically been known by two other names: f₀(600) and σ (sigma). A complete set of meson naming conventions is set forth in a 2017 review article for the Particle Data Group which also contains a table mapping pre-2016 common names to the new Particle Data Group standard naming conventions for XYZ mesons.

Meson properties

The following lists details for all known and predicted pseudoscalar ( J^P = 0⁻) and vector ( J^P = 1⁻) mesons. The properties and quark content of the particles are tabulated below; for the corresponding antiparticles, simply change quarks into antiquarks (and vice versa) and flip the sign of Q, B, S, C, and B′. Particles with ^† next to their names have been predicted by the

standard model The Standard Model of particle physics is the theory describing three of the four known fundamental forces ( electromagnetic, weak and strong interactions - excluding gravity) in the universe and classifying all known elementary particles. It ...

but not yet observed. Values in have not been firmly established by experiments, but are predicted by the

quark model In particle physics, the quark model is a classification scheme for hadrons in terms of their valence quarks—the quarks and antiquarks which give rise to the quantum numbers of the hadrons. The quark model underlies "flavor SU(3)", or the Ei ...

and are consistent with the measurements.

Pseudoscalar mesons

\, , , 0⁻ , 0⁻⁺ , 0 , 0 , 0 , , , - , style="text-align:left", Eta mesonK.A. Olive ''et al''. (2014)
Particle listings –
/ref> , , Self , }\, , , 0⁺ , 0⁻⁺ , 0 , 0 , 0 , , or

, - , style="text-align:left", Eta prime mesonK.A. Olive ''et al''. (2014)
Particle listings –
/ref> , (958) , Self , \, , , 0⁺ , 0⁻⁺ , 0 , 0 , 0 , ,

, - , style="text-align:left", Charmed eta mesonK.A. Olive ''et al''. (2014)
Particle listings –
/ref> , (1S) , Self , , , 0⁺ , 0⁻⁺ , 0 , 0 , 0 ,
See decay modes
, - , style="text-align:left", Bottom eta mesonK.A. Olive ''et al''. (2014)
Particle listings –
/ref> , (1S) , Self , , , , ⁺ , 0 , 0 , 0 , Unknown
See decay modes
, - , style="text-align:left", KaonK.A. Olive ''et al''. (2014)
Particle listings –
/ref> , , , , , , 0⁻ , 1 , 0 , 0 , ,

, - , style="text-align:left", KaonK.A. Olive ''et al''. (2014)
Particle listings –
/ref> , , , , , , 0⁻ , 1 , 0 , 0 , , , - , style="text-align:left", K-ShortK.A. Olive ''et al''. (2014)
Particle listings –
/ref> , , Self , }\, , , , 0⁻ , (*) , 0 , 0 , ,
, - , style="text-align:left", K-LongK.A. Olive ''et al''. (2014)
Particle listings –
/ref> , , Self , }\, , , , 0⁻ , (*) , 0 , 0 , ,

, - , style="text-align:left", D mesonK.A. Olive ''et al''. (2014)
Particle listings –
/ref> , , , , , , 0⁻ , 0 , +1 , 0 ,
See decay modes
, - , style="text-align:left", D mesonK.A. Olive ''et al''. (2014)
Particle listings –
/ref> , , , , , , 0⁻ , 0 , +1 , 0 ,
See decay modes
, - , style="text-align:left" , strange D mesonK.A. Olive ''et al''. (2014)
Particle listings –
/ref> , , , , , 0 , 0 , +1 , +1 , 0 ,
See decay modes
, - , style="text-align:left" , B mesonK.A. Olive ''et al''. (2014)
Particle listings –
/ref> , , , , , , , 0 , 0 , +1 ,
See decay modes
, - , style="text-align:left" , B mesonK.A. Olive ''et al''. (2014)
Particle listings –
/ref> , , , , , , , 0 , 0 , +1 ,
See decay modes
, - , style="text-align:left" , Strange B mesonK.A. Olive ''et al''. (2014)
Particle listings –
/ref> , , , , , , , −1 , 0 , +1 ,
See decay modes
, - , style="text-align:left" , Charmed B mesonK.A. Olive ''et al''. (2014)
Particle listings –
/ref> , , , , , , , 0 , +1 , +1 ,
See decay modes
^{/sup> Makeup inexact due to non-zero quark masses.

^{/sup> PDG reports the resonance width (Γ). Here the conversion τ = is given instead.

^{/sup> Strong
Strong may refer to:

Education
* The Strong, an educational institution in Rochester, New York, United States
* Strong Hall (Lawrence, Kansas), an administrative hall of the University of Kansas
* Strong School, New Haven, Connecticut, United S ...
eigenstate

In quantum physics, a quantum state is a mathematical entity that provides a probability distribution for the outcomes of each possible measurement on a system. Knowledge of the quantum state together with the rules for the system's evolution in ...
. No definite lifetime (see kaon notes below)

^{/sup> The mass of the and are given as that of the . However, it is known that a difference between the masses of the and on the order of exists.

^{/sup> Weak

Weak may refer to:

Songs
* "Weak" (AJR song), 2016
* "Weak" (Melanie C song), 2011
* "Weak" (SWV song), 1993
* "Weak" (Skunk Anansie song), 1995
* "Weak", a song by Seether from '' Seether: 2002-2013''

Television episodes
* "Weak" (''Fear t ...
eigenstate

In quantum physics, a quantum state is a mathematical entity that provides a probability distribution for the outcomes of each possible measurement on a system. Knowledge of the quantum state together with the rules for the system's evolution in ...
. Makeup is missing small CP–violating term (see notes on neutral kaons below).

Vector mesons

,
, 1⁺
, 1⁻⁻
, 0
, 0
, 0
,
,
, -
, style="text-align:left" , Omega mesonK.A. Olive ''et al''. (2014)
Particle listings – (782)
/ref>
, (782)
, Self
, }
,
, 0⁻
, 1⁻⁻
, 0
, 0
, 0
,
,

, -
, style="text-align:left" , Phi mesonK.A. Olive ''et al''. (2014)
Particle listings –
/ref>
, (1020)
, Self
,
,
, 0⁻
, 1⁻⁻
, 0
, 0
, 0
,
,

, -
, style="text-align:left" , J/PsiK.A. Olive ''et al''. (2014)
Particle listings – J/Ψ
/ref>
,
, Self
,
,
, 0⁻
, 1⁻⁻
, 0
, 0
, 0
,

See (1S) decay modes
, -
, style="text-align:left" , Upsilon mesonK.A. Olive ''et al''. (2014)
Particle listings – (1S)
/ref>
, (1S)
, Self
,
,
, 0⁻
, 1⁻⁻
, 0
, 0
, 0
,

See (1S) decay modes
, -
, style="text-align:left" , KaonK.A. Olive ''et al''. (2014)
Particle listings – (892)
/ref>
,
,
,
,
,
, 1⁻
, 1
, 0
, 0
,

See (892) decay modes
, -
, style="text-align:left" , Kaon
,
,
,
,
,
, 1⁻
, 1
, 0
, 0
,

See (892) decay modes
, -
, style="text-align:left" , D mesonK.A. Olive ''et al''. (2014)
Particle listings – (2010)
/ref>
, (2010)
, (2010)
,
,
,
,
, 0
, +1
, 0
,
,

, -
, style="text-align:left" , D mesonK.A. Olive ''et al''. (2014)
Particle listings – (2007)
/ref>
, (2007)
, (2007)
,
,
,
,
, 0
, +1
, 0
,
,

, -
, style="text-align:left" , Strange D mesonK.A. Olive ''et al''. (2014)
Particle listings –
/ref>
,
,
,
,
,
,
, +1
, +1
, 0
,
,

, -
, style="text-align:left" , B mesonK.A. Olive ''et al''. (2014)
Particle listings –
/ref>
,
,
,
,
,
,
, 0
, 0
, +1
, Unknown
,
, -
, style="text-align:left" , B meson
,
,
,
,
,
,
, 0
, 0
, +1
, Unknown
,
, -
, style="text-align:left" , Strange B mesonK.A. Olive ''et al''. (2014)
Particle listings –
/ref>
,
,
,
,
,
,
, −1
, 0
, +1
, Unknown
,
, -
, style="text-align:left" , Charmed B meson^†
,
,
,
, Unknown
,
,
, 0
, +1
, +1
, Unknown
, Unknown

^{/sup> PDG reports the resonance width (Γ). Here the conversion τ = is given instead.

^{/sup> The exact value depends on the method used. See the given reference for detail.

Notes on neutral kaons

There are two complications with neutral kaon

KAON (Karlsruhe ontology) is an ontology infrastructure developed by the University of Karlsruhe and the Research Center for Information Technologies in Karlsruhe.
Its first incarnation was developed in 2002 and supported an enhanced version of ...
s:

*Due to neutral kaon mixing, the and are not eigenstate

In quantum physics, a quantum state is a mathematical entity that provides a probability distribution for the outcomes of each possible measurement on a system. Knowledge of the quantum state together with the rules for the system's evolution in ...
s of strangeness

In particle physics, strangeness ("''S''") is a property of particles, expressed as a quantum number, for describing decay of particles in strong and electromagnetic interactions which occur in a short period of time. The strangeness of a parti ...
. However, they ''are'' eigenstates of the weak force

Weak may refer to:

Songs
* Weak (AJR song), "Weak" (AJR song), 2016
* Weak (Melanie C song), "Weak" (Melanie C song), 2011
* Weak (SWV song), "Weak" (SWV song), 1993
* Weak (Skunk Anansie song), "Weak" (Skunk Anansie song), 1995
* "Weak", a song ...
, which determines how they decay, so these are the particles with definite lifetime.
*The linear combinations given in the table for the and are not exactly correct, since there is a small correction due to CP violation

In particle physics, CP violation is a violation of CP-symmetry (or charge conjugation parity symmetry): the combination of C-symmetry (charge symmetry) and P-symmetry ( parity symmetry). CP-symmetry states that the laws of physics should be t ...
. See CP violation in kaons.

Note that these issues also exist in principle for other neutral flavored mesons; however, the weak eigenstates are considered separate particles only for kaons because of their dramatically different lifetimes.J.W. Cronin (1980)

See also

* List of baryons

Baryons are composite particles made of three quarks, as opposed to mesons, which are composite particles made of one quark and one antiquark. Baryons and mesons are both hadrons, which are particles composed solely of quarks or both quarks and ...

* List of particles
* Timeline of particle discoveries

This is a timeline of subatomic particle discoveries, including all particles thus far discovered which appear to be elementary (that is, indivisible) given the best available evidence. It also includes the discovery of composite particles and an ...

References

Bibliography

*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*

External links

*Particle Data Group The Particle Data Group (or PDG) is an international collaboration of particle physicists that compiles and reanalyzes published results related to the properties of particles and fundamental interactions. It also publishes reviews of theoretical ...
�
The Review of Particle Physics (2008)

Mesons made thinkable
an interactive visualisation allowing physical properties to be compared

{{particles

*
Mesons

In particle physics, a meson ( or ) is a type of hadronic subatomic particle composed of an equal number of quarks and antiquarks, usually one of each, bound together by the strong interaction. Because mesons are composed of quark subparticles, ...

it:Lista dei mesoni}}}}}}}