Meson

In

Higher-energy (more massive) mesons were created momentarily in the Big Bang, but are not thought to play a role in nature today. However, such heavy mesons are regularly created in particle accelerator experiments that explore the nature of the heavier quarks that compose the heavier mesons.

Mesons are part of the hadron particle family, which are defined simply as particles composed of two or more quarks. The other members of the hadron family are the baryons: subatomic particles composed of odd numbers of valence quarks (at least three), and some experiments show evidence of exotic mesons, which do not have the conventional valence quark content of two quarks (one quark and one antiquark), but four or more.

Because quarks have a spin 1/2, the difference in quark number between mesons and baryons results in conventional two-quark mesons being bosons, whereas baryons are fermions.

Each type of meson has a corresponding antiparticle (antimeson) in which quarks are replaced by their corresponding antiquarks and vice versa. For example, a positive pion (
π⁺
) is made of one up quark and one down antiquark; and its corresponding antiparticle, the negative pion (
π⁻
), is made of one up antiquark and one down quark.

Because mesons are composed of quarks, they participate in both the

The first candidate for Yukawa's meson, in modern terminology known as the muon, was discovered in 1936 by Carl David Anderson and others in the decay products of cosmic ray interactions. The "mu meson" had about the right mass to be Yukawa's carrier of the strong nuclear force, but over the course of the next decade, it became evident that it was not the right particle. It was eventually found that the "mu meson" did not participate in the strong nuclear interaction at all, but rather behaved like a heavy version of the electron, and was eventually classed as a lepton like the electron, rather than a meson. Physicists in making this choice decided that properties other than particle mass should control their classification.

There were years of delays in the subatomic particle research during

For a while in the past, the word meson was sometimes used to mean any force carrier, such as "the Z⁰ meson", which is involved in mediating the weak interaction.^[11] However, this use has fallen out of favor, and mesons are now defined as particles composed of pairs of quarks and antiquarks.

Overview

Spin, orbital angular momentum, and total angular momentum

Spin (quantum number S) is a vector quantity that represents the "intrinsic" angular momentum of a particle. It comes in increments of 1/2 ħ.^[A]

Quarks are fermions—specifically in this case, particles having spin 1/2 ( S = 1/2 ). Because spin projections vary in increments of 1 (that is 1 ħ), a single quark has a spin vector of length 1/2, and has two spin projections, either ( S_z = +1/2 or S_z = −+1/2 ). Two quarks can have their spins aligned, in which case the two spin vectors add to make a vector of length S = 1 , with three possible spin projections ( S_z = +1, S_z = 0, and S_z = −1), and their combination is called a vector meson or spin-1 triplet. If two quarks have oppositely aligned spins, the spin vectors add up to make a vector of length S = 0, and only one spin projection ( S_z = 0 ), called a scalar meson or spin-0 singlet. Because mesons are made of one quark and one antiquark, they are found in triplet and singlet spin states. The latter are called scalar mesons or pseudoscalar mesons, depending on their parity (see below).

There is another quantity of quantized angular momentum, called the orbital angular momentum (quantum number L), that is the angular momentum due to quarks orbiting each other, and also comes in increments of 1 ħ. The total angular momentum (quantum number J) of a particle is the combination of the two intrinsic angular momentums (spin) and the orbital angular momentum. It can take any value from J = |L − S| up to J = |L + S| , in increments of 1.

Particle physicists are most interested in mesons with no orbital angular momentum (L = 0), therefore the two groups of mesons most studied are the S = 1; L = 0 and S = 0; L = 0, which corresponds to J = 1 and J = 0, although they are not the only ones. It is also possible to obtain J = 1 particles from S = 0 and L = 1. How to distinguish between the S = 1, L = 0 and S = 0, L = 1 mesons is an active area of research in

P-parity is left-right parity, or spatial parity, and was the first of several "parities" discovered, and so is often called just

Based on this, one might think that, if the

For mesons, parity is related to the orbital angular momentum by the relation:^[13][14]

${\displaystyle P=\left(-1\right)^{L+1}}$

where the L is a result of the parity of the corresponding

C-parity is only defined for mesons that are their own antiparticle (i.e. neutral mesons). It represents whether or not the wavefunction of the meson remains the same under the interchange of their quark with their antiquark.[15] If

${\displaystyle |q{\bar {q}}\rangle =|{\bar {q}}q\rangle }$

then, the meson is "C even" (C = +1). On the other hand, if

${\displaystyle |q{\bar {q}}\rangle =-|{\bar {q}}q\rangle }$

then the meson is "C odd" (C = −1).

C-parity rarely is studied on its own, but more commonly in combination with P-parity into

G-parity is a generalization of the C-parity. Instead of simply comparing the wavefunction after exchanging quarks and antiquarks, it compares the wavefunction after exchanging the meson for the corresponding antimeson, regardless of quark content.^[19]

If

${\displaystyle |q_{1}{\bar {q}}_{2}\rangle =|{\bar {q}}_{1}q_{2}\rangle }$

then, the meson is "G even" (G = +1). On the other hand, if

${\displaystyle |q_{1}{\bar {q}}_{2}\rangle =-|{\bar {q}}_{1}q_{2}\rangle }$

then the meson is "G odd" (G = −1).

Isospin and charge

Original isospin model

The concept of isospin was first proposed by Werner Heisenberg in 1932 to explain the similarities between protons and neutrons under the strong interaction.^[20] Although they had different electric charges, their masses were so similar that physicists believed that they were actually the same particle. The different electric charges were explained as being the result of some unknown excitation similar to spin. This unknown excitation was later dubbed isospin by Eugene Wigner in 1937.^[21]

When the first mesons were discovered, they too were seen through the eyes of isospin and so the three pions were believed to be the same particle, but in different isospin states.

The mathematics of isospin was modeled after the mathematics of spin. Isospin projections varied in increments of 1 just like those of spin, and to each projection was associated a "charged state". Because the "pion particle" had three "charged states", it was said to be of isospin I = 1 . Its "charged states"
π⁺
,
π⁰
, and
π⁻
, corresponded to the isospin projections I₃ = +1 , I₃ = 0 , and I₃ = −1 respectively. Another example is the "rho particle", also with three charged states. Its "charged states"
ρ⁺
,
ρ⁰
, and
ρ⁻
, corresponded to the isospin projections I₃ = +1 , I₃ = 0 , and I₃ = −1 respectively.

Replacement by the quark model

This belief lasted until Murray Gell-Mann proposed the quark model in 1964 (containing originally only the u, d, and s quarks).^[22] The success of the isospin model is now understood to be an artifact of the similar masses of the u and d quarks. Because the u and d quarks have similar masses, particles made of the same number of them also have similar masses.

The exact u and d quark composition determines the charge, because u quarks carry charge ++2/3 whereas d quarks carry charge −+1/3. For example, the three pions all have different charges

• 
  π⁺
  = (
  u
  
  d
  )
• 
  π⁰
  = a quantum superposition of (
  u
  
  u
  ) and (
  d
  
  d
  ) states
• 
  π⁻
  = (
  d
  
  u
  )

but they all have similar masses (c. 140 MeV/c²) as they are each composed of a same total number of up and down quarks and antiquarks. Under the isospin model, they were considered a single particle in different charged states.

After the quark model was adopted, physicists noted that the isospin projections were related to the up and down quark content of particles by the relation

${\displaystyle I_{3}={\frac {1}{2}}\left[\left(n_{\text{u}}-n_{\bar {\text{u}}}\right)-\left(n_{\text{d}}-n_{\bar {\text{d}}}\right)\right],}$

where the n-symbols are the count of up and down quarks and antiquarks.

In the "isospin picture", the three pions and three rhos were thought to be the different states of two particles. However, in the quark model, the rhos are excited states of pions. Isospin, although conveying an inaccurate picture of things, is still used to classify hadrons, leading to unnatural and often confusing nomenclature.

Because mesons are hadrons, the isospin classification is also used for them all, with the quantum number calculated by adding I₃ = +1/2 for each positively charged up-or-down quark-or-antiquark (up quarks and down antiquarks), and I₃ = −1/2 for each negatively charged up-or-down quark-or-antiquark (up antiquarks and down quarks).

Flavour quantum numbers

The

It was noted that charge (Q) was related to the isospin projection (I₃), the baryon number (B) and flavour quantum numbers (S, C, B′, T) by the Gell-Mann–Nishijima formula:^[23]

${\displaystyle Q=I_{3}+{\frac {1}{2}}(B+S+C+B^{\prime }+T),}$

where S, C, B′, and T represent the strangeness, charm, bottomness and topness flavour quantum numbers respectively. They are related to the number of strange, charm, bottom, and top quarks and antiquark according to the relations:

${\displaystyle {\begin{aligned}S&=-(n_{\text{s}}-n_{\bar {\text{s}}})\\C&=+(n_{\text{c}}-n_{\bar {\text{c}}})\\B^{\prime }&=-(n_{\text{b}}-n_{\bar {\text{b}}})\\T&=+(n_{\text{t}}-n_{\bar {\text{t}}}),\end{aligned}}}$

meaning that the Gell-Mann–Nishijima formula is equivalent to the expression of charge in terms of quark content:

${\displaystyle Q={\frac {2}{3}}[(n_{\text{u}}-n_{\bar {\text{u}}})+(n_{\text{c}}-n_{\bar {\text{c}}})+(n_{\text{t}}-n_{\bar {\text{t}}})]-{\frac {1}{3}}[(n_{\text{d}}-n_{\bar {\text{d}}})+(n_{\text{s}}-n_{\bar {\text{s}}})+(n_{\text{b}}-n_{\bar {\text{b}}})].}$

Classification

Mesons are classified into groups according to their

Nomenclature of flavourless mesons

q q content	I	C [ii]
		0−+, 2−+, 4−+, ...	1+−, 3+−, 5+−, ...	1−−, 2−−, 3−−, ...	0++, 1++, 2++, ...
u d ${\displaystyle \mathrm {\tfrac {u{\bar {u}}-d{\bar {d}}}{\sqrt {2}}} }$ d u	1	π+ π0 π−	b+ b0 b−	ρ+ ρ0 ρ−	a+ a0 a−
Mix of u u , d d , s s	0	η′	h h′	ω ϕ	f f′
c c	0	η c	hc	ψ[iii]	χc
b b	0	η b	hb	ϒ	χb
t t	0	η t	ht	θ	χt

In addition

• When the
  spectroscopic state
  of the meson is known, it is added in parentheses.
• When the spectroscopic state is unknown, mass (in MeV/c²) is added in parentheses.
• When the meson is in its ground state, nothing is added in parentheses.

Flavoured mesons

Flavoured mesons are mesons made of pair of quark and antiquarks of different flavours. The rules are simpler in this case: The main symbol depends on the heavier quark, the superscript depends on the charge, and the subscript (if any) depends on the lighter quark. In table form, they are:^[24]

Nomenclature of flavoured mesons

Quark	Antiquark
	up	down	charm	strange	top	bottom
up	—	[i]	D0	K+	T0	B+
down	[i]	—	D−	K0	T−	B0
charm	D0	D+	—	D+ s	T0 c	B+ c
strange	K−	K0	D− s	—	T− s	B0 s
top	T0	T+	T0 c	T+ s	—	T+ b
bottom	B−	B0	B− c	B0 s	T− b	—

1. ^ ^{a b} For the purpose of nomenclature, the isospin projection I₃ is treated as if it were not a flavour quantum number. This means that the charged pion-like mesons (π^±, a^±, b^±, and ρ^± mesons) follow the rules of flavourless mesons, even if they aren't truly "flavourless".

In addition

• If
  J^P
  = 0⁺, 1⁻, 2⁺, 3⁻, ...), a superscript ∗ is added.
• If the meson is not pseudoscalar (
  J^P
  = 1⁻), J is added as a subscript.
• When the
  spectroscopic state
  of the meson is known, it is added in parentheses.
• When the spectroscopic state is unknown, mass (in MeV/c²) is added in parentheses.
• When the meson is in its ground state, nothing is added in parentheses.

Exotic mesons

Main article: Exotic meson

There is experimental evidence for particles that are hadrons (i.e., are composed of quarks) and are color-neutral with zero baryon number, and thus by conventional definition are mesons. Yet, these particles do not consist of a single quark/antiquark pair, as all the other conventional mesons discussed above do. A tentative category for these particles is exotic mesons.

There are at least five exotic meson resonances that have been experimentally confirmed to exist by two or more independent experiments. The most statistically significant of these is the

LHCb in 2014. It is a candidate for being a tetraquark: a particle composed of two quarks and two antiquarks.^[26]

See the main article above for other particle resonances that are candidates for being exotic mesons.

List

Main article: List of mesons

Pseudoscalar mesons

Particle name	Particle symbol	Antiparticle symbol	Quark content	MeV/c 2)	G	C	S	C	B'	Mean lifetime (s )	Commonly decays to (>5% of decays)
Pion[27]	π+	π−	d	139.57018±0.00035	1−	0−	0	0	0	(2.6033±0.0005)×10−8	μ+ + ν μ
Pion[28]	π0	Self	${\displaystyle \mathrm {\tfrac {u{\bar {u}}-d{\bar {d}}}{\sqrt {2}}} \,}$[a]	134.9766±0.0006	1−	0−+	0	0	0	(8.4±0.6)×10−17	γ + γ
Eta meson[29]	η	Self	${\displaystyle \mathrm {\tfrac {u{\bar {u}}+d{\bar {d}}-2s{\bar {s}}}{\sqrt {6}}} \,}$[a]	547.853±0.024	0+	0−+	0	0	0	(5.0±0.3)×10−19[b]	γ + γ or π0 + π0 + π0 or π+ + π0 + π−
Eta prime meson[30]	η′ (958)	Self	${\displaystyle \mathrm {\tfrac {u{\bar {u}}+d{\bar {d}}+s{\bar {s}}}{\sqrt {3}}} \,}$[a]	957.66±0.24	0+	0−+	0	0	0	(3.2±0.2)×10−21[b]	η
Charmed eta meson[31]	η c (1S)	Self	c	2980.3±1.2	0+	0−+	0	0	0	(2.5±0.3)×10−23[b]	See η c decay modes
Bottom eta meson[32]	η b(1S)	Self	b	9300±40	0+	0−+	0	0	0	Unknown	See η b decay modes
Kaon[33]	K+	K−	s	493.677±0.016	1⁄2	0−	1	0	0	(1.2380±0.0021)×10−8	μ+ + ν μ or π+ + π0 or π0 + e+ + ν e or π+ + π0
Kaon[34]	K0	K0	s	497.614±0.024	1⁄2	0−	1	0	0	[c]	[c]
K-Short[35]	K0 S	Self	${\displaystyle \mathrm {\tfrac {d{\bar {s}}+s{\bar {d}}}{\sqrt {2}}} \,}$[e]	497.614±0.024[d]	1⁄2	0−	(*)	0	0	(8.953±0.005)×10−11	π+ + π− or π0 + π0
K-Long[36]	K0 L	Self	${\displaystyle \mathrm {\tfrac {d{\bar {s}}-s{\bar {d}}}{\sqrt {2}}} \,}$[e]	497.614±0.024[d]	1⁄2	0−	(*)	0	0	(5.116±0.020)×10−8	π± + e∓ + ν e or π± + μ∓ + ν μ or π0 + π0 + π0 or π+ + π0 + π−
D meson[37]	D+	D−	d	1869.62±0.20	1⁄2	0−	0	+1	0	(1.040±0.007)×10−12	See D+ decay modes
D meson[38]	D0	D0	u	1864.84±0.17	1⁄2	0−	0	+1	0	(4.101±0.015)×10−13	See D0 decay modes
strange D meson[39]	D+ s	D− s	s	1968.49±0.34	0	0−	+1	+1	0	(5.00±0.07)×10−13	See D+ s decay modes
B meson[40]	B+	B−	b	5279.15±0.31	1⁄2	0−	0	0	+1	(1.638±0.011)×10−12	See B+ decay modes
B meson[41]	B0	B0	b	5279.53±33	1⁄2	0−	0	0	+1	(1.530±0.009)×10−12	See B0 decay modes
Strange B meson[42]	B0 s	B0 s	b	5366.3±0.6	0	0−	−1	0	+1	1.470+0.026 −0.027×10−12	See B0 s decay modes
Charmed B meson[43]	B+ c	B− c	b	6276±4	0	0−	0	+1	+1	(4.6±0.7)×10−13	See B+ c decay modes

^[a] ^ Makeup inexact due to non-zero quark masses.
^[b]

resonance width

(Γ). Here the conversion τ = ħ⁄Γ is given instead.
^[c]

eigenstate. No definite lifetime (see kaon notes

below)
^[d] ^ The mass of the
K⁰
_L and
K⁰
_S are given as that of the
K⁰
. However, it is known that a difference between the masses of the
K⁰
_L and
K⁰
_S on the order of 2.2×10⁻¹¹ MeV/c² exists.^[36]
[e]

eigenstate. Makeup is missing small CP–violating term (see notes on neutral kaons

below).

Vector mesons

Particle name	Particle symbol	Antiparticle symbol	Quark content	MeV/c 2)	G	C	S	C	B'	Mean lifetime (s )	Commonly decays to (>5% of decays)
Charged rho meson[44]	ρ+ (770)	ρ− (770)	d	775.4±0.4	1+	1−	0	0	0	~4.5×10−24[f][g]	π± + π0
Neutral rho meson[44]	ρ0 (770)	Self	${\displaystyle \mathrm {\tfrac {u{\bar {u}}-d{\bar {d}}}{\sqrt {2}}} }$	775.49±0.34	1+	1−−	0	0	0	~4.5×10−24[f][g]	π+ + π−
Omega meson[45]	ω (782)	Self	${\displaystyle \mathrm {\tfrac {u{\bar {u}}+d{\bar {d}}}{\sqrt {2}}} }$	782.65±0.12	0−	1−−	0	0	0	(7.75±0.07)×10−23[f]	π+ + π0 + π− or π0 + γ
Phi meson[46]	ϕ (1020)	Self	s	1019.445±0.020	0−	1−−	0	0	0	(1.55±0.01)×10−22[f]	K+ + K− or K0 S + K0 L or ( ρ + π ) / ( π+ + π0 + π− )
J/Psi[47]	J/ψ	Self	c	3096.916±0.011	0−	1−−	0	0	0	(7.1±0.2)×10−21[f]	See J/ψ (1S) decay modes
Upsilon meson[48]	ϒ (1S)	Self	b	9460.30±0.26	0−	1−−	0	0	0	(1.22±0.03)×10−20[f]	See ϒ (1S) decay modes
Kaon[49]	K∗+	K∗−	s	891.66±0.026	1⁄2	1−	1	0	0	~7.35×10−20[f][g]	See K∗ (892) decay modes
Kaon[49]	K∗0	K∗0	s	896.00±0.025	1⁄2	1−	1	0	0	(7.346±0.002)×10−20[f]	See K∗ (892) decay modes
D meson[50]	D∗+ (2010)	D∗− (2010)	d	2010.27±0.17	1⁄2	1−	0	+1	0	(6.9±1.9)×10−21[f]	D0 + π+ or D+ + π0
D meson[51]	D∗0 (2007)	D∗0 (2007)	u	2006.97±0.19	1⁄2	1−	0	+1	0	>3.1×10−22[f]	D0 + π0 or D0 + γ
strange D meson[52]	D∗+ s	D∗− s	s	2112.3±0.5	0	1−	+1	+1	0	>3.4×10−22[f]	D∗+ + γ or D∗+ + π0
B meson[53]	B∗+	B∗−	b	5325.1±0.5	1⁄2	1−	0	0	+1	Unknown	B+ + γ
B meson[53]	B∗0	B∗0	b	5325.1±0.5	1⁄2	1−	0	0	+1	Unknown	B0 + γ
Strange B meson[54]	B∗0 s	B∗0 s	b	5412.8±1.3	0	1−	−1	0	+1	Unknown	B0 s+ γ
Charmed B meson†	B∗+ c	B∗− c	b	Unknown	0	1−	0	+1	+1	Unknown	Unknown

^[f]

resonance width

(Γ). Here the conversion τ = ħ⁄Γ is given instead.
^[g] ^ The exact value depends on the method used. See the given reference for detail.

Notes on neutral kaons

There are two complications with neutral kaons:^[55]

• Due to
  lifetime
  .
• The linear combinations given in the table for the
  K⁰
  _S and
  K⁰
  _L are not exactly correct, since there is a small correction due to CP violation. 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.^[55]

See also

• Mesonic molecule
• Standard Model

Footnotes

1. ^ The ħ is often dropped because it is the "fundamental" unit of spin, and it is implied that "spin 1" means "spin 1 ħ". In some systems of natural units, ħ is chosen to be 1, and therefore drops out of equations. The remainder of this article uses the "assume ħ units" convention for all types of spin.

References

1. ISBN 978-3-527-40601-2
   .
2. ^ Aubert, J.J.; Becker, U.; Biggs, P.; Burger, J.; Chen, M.; Everhart, G.; et al. (1974). "Experimental observation of a Heavy Particle J".
   doi:10.1103/PhysRevLett.33.1404
   .
3. ^ Augustin, J.E.; Boyarski, A.; Breidenbach, M.; Bulos, F.; Dakin, J.; Feldman, G.; et al. (1974). "Discovery of a narrow resonance in e⁺e⁻ annihilation".
   doi:10.1103/PhysRevLett.33.1406
   .
4. ^ Herb, S. W.; Hom, D.; Lederman, L.; Sens, J.; Snyder, H.; Yoh, J.; et al. (1977). "Observation of a di-muon resonance at 9.5 GeV in 400 GeV proton-nucleus collisions".
   OSTI 1155396
   .
5. ^ "Nobel Prize in Physics 1949". Presentation Speech. The Noble Foundation. 1949.
6. ^ Yukawa, H. (1935). "On the Interaction of Elementary Particles" (PDF). Proc. Phys.-Math. Soc. Jpn. 17 (48).
7. doi:10.11429/ppmsj1919.17.0_48
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8. ISBN 978-0-486-25767-9
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9. ^ "D. M. Bose: A Scientist Incognito (editorial)" (PDF). Science and Culture. 76 (11–12). November–December 2010. Retrieved 5 February 2011.
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11. PMID 17747881
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12. ^ "Particles of the Standard Model". pdfslide.net. Retrieved 24 May 2020.
13. ^ Amsler, C.; et al. (
    Lawrence Berkeley Laboratory
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14. ^ Amsler, C.; et al. (
    S2CID 227119789
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15. ISBN 978-0-19-929666-8
    .
16. ^ Cronin, J.W. (1980). "CP Symmetry Violation—The Search for its origin" (PDF). The Nobel Foundation.
17. ^ Fitch, V.L. (1980). "The Discovery of Charge—Conjugation Parity Asymmetry" (PDF). The Nobel Foundation.
18. ISBN 978-0-19-929666-8
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19. ISBN 0-19-503393-0
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20. ^
    S2CID 186218053
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21. doi:10.1103/PhysRev.51.106
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22. doi:10.1016/S0031-9163(64)92001-3
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23. ISBN 0-471-23973-9
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24. ^ ^{a b c} Amsler, C.; et al. (
    Lawrence Berkeley Laboratory
    .
25. ISBN 0-582-45088-8
    .
26. ^ LHCb collaborators (2014): Observation of the resonant character of the Z(4430)− state
27. ^ C. Amsler et al. (2008): Particle listings –
    π^±
    
28. ^ C. Amsler et al. (2008): Particle listings –
    π⁰
    
29. ^ C. Amsler et al. (2008): Particle listings –
    η
    
30. ^ C. Amsler et al. (2008): Particle listings –
    η′
    
31. ^ C. Amsler et al. (2008): Particle listings –
    η
    _c
32. ^ C. Amsler et al. (2008): Particle listings –
    η
    _b
33. ^ C. Amsler et al. (2008): Particle listings –
    K^±
    
34. ^ C. Amsler et al. (2008): Particle listings –
    K⁰
    
35. ^ C. Amsler et al. (2008): Particle listings –
    K⁰
    _S
36. ^ ^{a b} C. Amsler et al. (2008): Particle listings –
    K⁰
    _L
37. ^ C. Amsler et al. (2008): Particle listings –
    D^±
    
38. ^ C. Amsler et al. (2008): Particle listings –
    D⁰
    
39. ^ C. Amsler et al. (2008): Particle listings –
    D^±
    _s
40. ^ C. Amsler et al. (2008): Particle listings –
    B^±
    
41. ^ C. Amsler et al. (2008): Particle listings –
    B⁰
    
42. ^ C. Amsler et al. (2008): Particle listings –
    B⁰
    _s
43. ^ C. Amsler et al. (2008): Particle listings –
    B^±
    _c
44. ^ ^{a b} C. Amsler et al. (2008): Particle listings –
    ρ
    
45. ^ C. Amsler et al. (2008): Particle listings –
    ω
    (782)
46. ^ C. Amsler et al. (2008): Particle listings –
    ϕ
    
47. ^ C. Amsler et al. (2008): Particle listings – J/Ψ
48. ^ C. Amsler et al. (2008): Particle listings –
    ϒ
    (1S)
49. ^ ^{a b} C. Amsler et al. (2008): Particle listings –
    K^∗
    (892)
50. ^ C. Amsler et al. (2008): Particle listings –
    D^∗±
    (2010)
51. ^ C. Amsler et al. (2008): Particle listings –
    D^∗0
    (2007)
52. ^ C. Amsler et al. (2008): Particle listings –
    D^∗±
    _s
53. ^ ^{a b} C. Amsler et al. (2008): Particle listings –
    B^∗
    
54. ^ C. Amsler et al. (2008): Particle listings –
    B^∗
    _s
55. ^ ^{a b} J.W. Cronin (1980)

External links

• Nave, C.R., ed. (2005). "A table of some mesons and their properties". Department of Physics and Astronomy. Hyperphysics. Atlanta, GA: Georgia State University.
• "Particle Data Group".
  Lawrence Berkeley Laboratory
  (main page). Lawrence, CA. — Compiles authoritative information on particle properties
• van Beveren, Eef; Rupp, George; Petropoulos, Nicholas; Kleefeld, Frieder (2003) [26 Nov 2002]. "The light scalar mesons within quark models". American Institute of Physics Conference Proceedings. 660: 353–366.
  S2CID 6295609
  .
• "Naming scheme for hadrons" (PDF).
  Lawrence Berkeley Laboratory
  . 2004.
• "Mesons made thinkable". thingsmadethinkable.com. — An interactive visualisation allowing physical properties to be compared
• Perricone, Mike (22 March 2006). "What happened to the antimatter? Fermilab's DZero experiment finds clues in quick-change meson" (Press release). Batavia, IL:
  Fermi National Accelerator Laboratory
  (Fermilab).
• Perricone, Mike (25 September 2006). "Fermilab's CDF scientists make it official: They have discovered the quick-change behavior of the B-sub-s meson, which switches between matter and antimatter 3 trillion times a second" (Press release). Batavia, IL:
  Fermi National Accelerator Laboratory
  (Fermilab).