Physics:List of mesons

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The decay of a kaon (K+) into three pions (2 π+, 1 π) is a process that involves both weak and strong interactions.

Weak interactions: The strange antiquark (s) of the kaon transmutes into an up antiquark (u) by the emission of a W+ boson; the W+ boson subsequently decays into a down antiquark (d) and an up quark (u).

Strong interactions: An up quark (u) emits a gluon (g) which decays into a down quark (d) and a down antiquark (d).
This list is of all known and predicted scalar, pseudoscalar and vector mesons. See list of particles for a more detailed list of particles found in particle physics.

This article contains a list of mesons, unstable subatomic particles composed of one quark and one antiquark. They are part of the hadron particle family—particles made of quarks. The other members of the hadron family are the baryons—subatomic particles composed of three quarks. The main difference between mesons and baryons is that mesons have integer spin (thus are bosons) while baryons are fermions (half-integer spin). Because mesons are bosons, the Pauli exclusion principle 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 and strong interactions. Mesons with net electric charge also participate in the electromagnetic interaction. They are classified according to their quark content, total angular momentum, parity, and various other properties such as C-parity and G-parity. While no meson is stable, those of lower mass are nonetheless more stable than the most massive mesons, and are easier to observe and study in particle accelerators or in cosmic ray 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 (J/ψ) in 1974,[1][2] and the bottom quark in the upsilon meson (ϒ) in 1977.[3] The top quark (the last and heaviest quark to be discovered to date) was first observed at Fermilab in 1995.

Each meson has a corresponding antiparticle (antimeson) where 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. 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), J (total angular momentum), P (parity), C (C-parity), G (G-parity), u (up quark), d (down quark), s (strange quark), c (charm quark), b (bottom quark), Q (charge), B (baryon number), S (strangeness), C (charm), and B′ (bottomness), 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.

Meson summary table[4]
Light unflavoured
(S = C = B = 0)
Strange
(S = ±1, C = B = 0)
Charmed, strange
(C = S = ±1)
cc
IG(JPC) IG(JPC) IG(JP) IG(JP) IG(JPC)
π± 1(0) Φ(1680) 0(1−−) K± 12(0) D±s 0(0) ηc(1S) 0+(0−+)
π0 1(0−+) ρ3(1690) 1+(3−−) K0 12(0) Ds 0(??) J/ψ(1S) 0(1−−)
η 0+(0−+) ρ(1700) 1+(1−−) K0S 12(0) D*s0(2317)± 0(0+) χc0(1P) 0+(0++)
f0(500) 0+(0++) a2(1700) 1(2++) K0L 12(0) Ds1(2460)± 0(1+) χc1(1P) 0+(1++)
ρ(770) 1+(1−−) f0(1710) 0+(0++) K*0(800) 12(0+) Ds1(2536)± 0(1+) hc(1P) ??(1+−)
ω(782) 0(1−−) η(1760) 0+(0−+) K*(892) 12(1) Ds2(2573) 0(??) χc2(1P) 0+(2++)
η′ (958) 0+(0−+) π(1800) 1(0−+) K1(1270) 12(1+) D*s1(2700)± 0(1) ηc(2S) 0+(0−+)
f0(980) 0+(0++) f2(1810) 0+(2++) K1(1400) 12(1+) D*sJ(2860)± 0(??) ψ(2S) 0(1−−)
a0(980) 1(0++) X(1835) ??(?−+) K*(1410) 12(1) DsJ(3040)± 0(??) ψ(3770) 0(1−−)
φ(1020) 0(1−−) X(1840) ??(???) K*0(1430) 12(0+) Bottom
(B = ±1)
X(3823) ??(??−)
h1(1170) 0(1+−) φ3(1850) 0(3−−) K*2(1430) 12(2+) X(3872) 0+(1++)
b1(1235) 1+(1+−) η2(1870) 0+(2−+) K(1460) 12(0) B± 12(0) X(3900)± ?(1+)
a1(1260) 1(1++) π2(1880) 1(2−+) K2(1580) 12(2) B0 12(0) X(3900)0 ?(??)
f2(1270) 0+(2++) ρ(1900) 1+(1−−) K(1630) 12(??) B±/B0 Admixture χc0(2P) 0+(0++)
f1(1285) 0+(1++) f2(1910) 0+(2++) K1(1650) 12(1+) B±/B0/B0s/b-baryon
Admixture
χc2(2P) 0+(2++)
η(1295) 0+(0−+) f2(1950) 0+(2++) K*(1680) 12(1) X(3940) ??(???)
π(1300) 1(0−+) ρ3(1990) 1+(3−−) K2(1770) 12(2) Vcb and Vub CKM Matrix
Admixture
X(4020)± ?(??)
a2(1320) 1(2++) f2(2010) 0+(2++) K*3(1780) 12(3) ψ(4040) 0(1−−)
f0(1370) 0+(0++) f0(2020) 0+(0++) K2(1820) 12(2) B* 12(1) X(4050)± ?(??)
h1(1380) ?(1+−) a4(2040) 1(4++) K(1830) 12(0) B*J(5732) ?(??) X(4140) 0+(??+)
π1(1400) 1(1−+) f4(2050) 0+(4++) K*0(1950) 12(0+) B1(5721)0 12(1+) ψ(4160) 0(1−−)
η(1405) 0+(0−+) π2(2100) 1(2−+) K*2(1980) 12(2+) B*1(5721)0 12(2+) X(4160) ??(???)
f1(1420) 0+(1++) f0(2100) 0+(0++) K*0(2045) 12(4+) Bottom, strange
(B = ±1, S = ∓1)
X(4250)± ?(??)
ω(1420) 0(1−−) f2(2150) 0+(2++) K2(2250) 12(2) X(4260) ??(1−−)
f2(1430) 0+(2++) ρ(2150) 1+(1−−) K3(2320) 12(3+) B0s 0(0) X(4350) 0+(??+)
a0(1450) 1(0++) φ(2170) 0(1−−) K*5(2380) 12(5) B*s 0(1) X(4360) ??(1−−)
ρ(1450) 1+(1−−) f0(2200) 0+(0++) k4(2500) 12(4) Bs1(5830)0 0(1+) ψ(4415) 0(1−−)
η(1475) 0+(0−+) fJ(2200) 0+(2++
or 4++)
K(3100) ??(???) B*s2(5840)0 0(2+) X(4430)± ?(1+)
f0(1500) 0+(0++) Charmed
(C = ±1)
B*sJ(5850) ?(??) X(4660) ??(1−−)
f1(1510) 0+(1++) η(2225) 0+(0−+) Bottom, charmed
(B = C = ±1)
bb
f′1(1525) 0+(2++) ρ3(2250) 1+(3−−) D± 12(0) ηb(1S) 0+(0−+)
f2(1565) 0+(2++) f2(2300) 0+(2++) D0 12(0) B±c 0(0) Υ(1S) 0(1−−)
ρ(1570) 1+(1−−) f4(2300) 0+(4++) D*(2007)0 12(1) χb0(1P) 0+(0++)
h1(1595) 0(1+−) f0(2330) 0+(0++) D*(2010)± 12(1) χb1(1P) 0+(1++)
π1(1600) 1(1−+) f2(2340) 0+(2++) D*0(2400)0 12(0+) χb0(2P) 0+(0++)
a1(1640) 1(1++) ρ5(2350) 1+(5−−) D*0(2400)± 12(0+) hb(1P) ??(1+−)
f2(1640) 0+(2++) a6(2450) 1(6++) D1(2420)0 12(1+) χb2(1P) 0+(2++)
η2(1645) 0+(2−+) f6(2510) 0+(6++) D1(2420)± 12(??) ηb(2S) 0+(0−+)
ω(1650) 0(1−−) Other light D1(2430)0 12(1+) Υ(2S) 0(1−−)
ω3(1670) 0(3−−) Further States D*2(2460)0 12(2+) Υ(1D) 0(2−−)
π2(1670) 1(2−+) D*2(2460)± 12(2+) χb0(2P) 0+(0++)
D(2550)0 12(0) χb1(2P) 0+(1++)
D(2600) 12(??) hb(2P) ??(1+−)
D*(2640)± 12(??) χb2(2P) 0+(2++)
D(2750) 12(??) Υ(3S) 0(1−−)
χb(3P) ??(??+)
Υ(4S) 0(1−−)
X(10610)± 1+(1+)
X(10610)0 1+(1+)
X(10650)± ?+(1+)
Υ(10860) 0(1−−)
Υ(11020) 0(1−−)

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 IG of 1+ and 0 respectively.[5]

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.[6][7] The particle described in the table above as f0(500) has historically been known by two other names: f0(600) and σ (sigma).[8]

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.[9]

Meson properties

The following lists details for all known and predicted pseudoscalar (JP = 0) and vector (JP = 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 but not yet observed. Values in red have not been firmly established by experiments, but are predicted by the quark model and are consistent with the measurements.

Pseudoscalar mesons

Pseudoscalar mesons
Particle
name
Particle
symbol
Antiparticle
symbol
Quark
content
Rest mass (MeV/c2) IG JPC S C B' Mean lifetime (s) Commonly decays to
(>5% of decays)
Pion[10] Pion+ Pion- Up quarkDown antiquark 0139.57018 139.57018±0.00035


1 0 0 0 0 -08.2 (2.6033±0.0005)×10−8


Antimuon + Muon neutrino
Pion[11] Pion0 Self [math]\displaystyle{ \mathrm{\tfrac{u\bar{u} - d\bar{d}}{\sqrt{2}}}\, }[/math][a] 0134.9766 134.9766±0.0006


1 0−+ 0 0 0 -17 (8.52±0.18)×10−17


Photon + Photon
Eta meson[12] Eta Self [math]\displaystyle{ \mathrm{\tfrac{u\bar{u} + d\bar{d} - 2s\bar{s}}{\sqrt{6}}}\, }[/math][a] 0547.862 547.862±0.018


0+ 0−+ 0 0 0 -19 (5.02±0.19)×10−19[b]


Photon + Photon or
Pion0 + Pion0 + Pion0 or
Pion+ + Pion0 + Pion-
Eta prime meson[13] Eta prime(958) Self [math]\displaystyle{ \tfrac\mathrm{u\bar{u} + d\bar{d} + s\bar{s}}{\sqrt{3}}\, }[/math][a] 0957.78 957.78±0.06


0+ 0−+ 0 0 0 -21 (3.32±0.15)×10−21[b]


Pion+ + Pion- + Eta or
(rho0 + Photon) / (Pion+ + Pion- + Photon) or
Pion0 + Pion0 + Eta
Charmed eta meson[14] Charmed eta(1S) Self charm quarkcharm antiquark 2,983.6±0.7 0+ 0−+ 0 0 0 -23 (2.04±0.05)×10−23[b]


See ηc decay modes
Bottom eta meson[15] Bottom eta(1S) Self bBottom antiquark 9,398.0±3.2 0+ 0+ 0 0 0 Unknown See ηb decay modes
Kaon[16] Kaon+ Kaon- Up quarkStrange antiquark 0493.677 493.677±0.016


12 0 1 0 0 -08.3 (1.2380±0.0021)×10−8


Antimuon + Muon neutrino or
pion+ + pion0 or
pion0 + positron + Electron neutrino or
pion+ + pion+ + pion-
Kaon[17] Kaon0 Antikaon0 Down quarkStrange antiquark 0497.614 497.614±0.024


12 0 1 0 0 [c] [c]
K-Short[18] K-short0 Self [math]\displaystyle{ \mathrm{\tfrac{d\bar{s} + s\bar{d}}{\sqrt{2}}}\, }[/math][e] 0497.614 497.614±0.024

[d]

12 0 (*) 0 0 -11 (8.954±0.004)×10−11


pion+ + pion- or

pion0 + pion0

K-Long[19] K0L Self [math]\displaystyle{ \mathrm{\tfrac{d\bar{s} - s\bar{d}}{\sqrt{2}}}\, }[/math][e] 0497.614 497.614±0.024

[d]

12 0 (*) 0 0 -08.1 (5.116±0.021)×10−8


Pion+- + electron-+ + Electron neutrino or
Pion+- + muon-+ + Muon neutrino or
Pion0 + Pion0 + Pion0 or
Pion+ + Pion0 + Pion-
D meson[20] D+ D- Charm quarkDown antiquark 1,869.61±0.10 12 0 0 +1 0 -12.4 (1.040±0.007)×10−12


See D+ decay modes
D meson[21] D0 AntiD0 Charm quarkup antiquark 1,864.84±0.07 12 0 0 +1 0 -13.3 (4.101±0.015)×10−13


See D0 decay modes
strange D meson[22] Strange D+ Strange D- Charm quarkstrange antiquark 1,968.30±0.11 0 0 +1 +1 0 -13.1 (5.00±0.07)×10−13


See D+s decay modes
B meson[23] B+ B- up quarkbottom antiquark 5,279.26±0.17 12 0 0 0 +1 -12.1 (1.638±0.004)×10−12


See B+ decay modes
B meson[24] B0 AntiB0 Down quarkBottom antiquark 5,279.58±0.17 12 0 0 0 +1 -12.2 (1.519±0.009)×10−12


See B0 decay modes
Strange B meson[25] Strange B0 Strange AntiB0 strange quarkBottom antiquark 5,366.77±0.24 0 0 −1 0 +1 -12.3 (1.512±0.007)×10−12


See B0s decay modes
Charmed B meson[26] Charmed B+ Charmed B- Charm quarkbottom antiquark 6,275.6±1.1 0 0 0 +1 +1 -13.2 (4.52±0.33)×10−13


See B+c decay modes

[a] ^ Makeup inexact due to non-zero quark masses.
[b] ^ PDG reports the resonance width (Γ). Here the conversion τ = ​ħΓ is given instead.
[c] ^ Strong eigenstate. No definite lifetime (see kaon notes below)
[d] ^ The mass of the K0L and K0S are given as that of the K0. However, it is known that a difference between the masses of the K0L and K0S on the order of 2.2×10−11 MeV/c2 exists.[19]
[e] ^ Weak eigenstate. Makeup is missing small CP–violating term (see notes on neutral kaons below).

Vector mesons

Vector mesons
Particle
name
Particle
symbol
Antiparticle
symbol
Quark
content
Rest mass (MeV/c2) IG JPC S C B' Mean lifetime (s) Commonly decays to
(>5% of decays)
Charged rho meson[27] Rho+(770) Rho-(770) Up quarkDown antiquark 0775.11 775.11±0.34


1+ 1 0 0 0 -24 (4.41±0.02)×10−24[f][g]


Pion+- + Pion0
Neutral rho meson[27] Rho0(770) Self [math]\displaystyle{ \mathrm{\tfrac{u\bar{u}-d\bar{d}}{\sqrt 2}} }[/math] 0775.26 775.26±0.25


1+ 1−− 0 0 0 -24 (4.45±0.03)×10−24[f][g]


Pion+ + Pion-
Omega meson[28] omega meson(782) Self [math]\displaystyle{ \mathrm{\tfrac{u\bar{u}+d\bar{d}}{\sqrt 2}} }[/math] 0783 782.65±0.12


0 1−− 0 0 0 -23 (7.75±0.07)×10−23[f]


Pion+ + Pion0 + Pion- or
Pion0 + Photon
Phi meson[29] Phi meson(1020) Self Strange quarkStrange antiquark 1,019.461±0.019 0 1−− 0 0 0 -22.3 (1.54±0.01)×10−22[f]


Kaon+ + Kaon- or
K-short0 + K0L or
(rho + pion) / (pion+ + pion0 + pion-)
J/Psi[30] J/Psi Self Charm quarkCharm antiquark 3,096.916±0.011 0 1−− 0 0 0 -21.1 (7.09±0.21)×10−21[f]


See J/ψ(1S) decay modes
Upsilon meson[31] Upsilon(1S) Self bbottom antiquark 9,460.30±0.26 0 1−− 0 0 0 -20.3 (1.22±0.03)×10−20[f]


See ϒ(1S) decay modes
Kaon[32] K∗+ K∗− Up quarkStrange antiquark 0892 891.66±0.26


12 1 1 0 0 -23.1 (3.26±0.06)×10−23[f][g]


See K(892) decay modes
Kaon[32] K∗0 Antikaon*0 Down quarkStrange antiquark 0896 895.81±0.19


12 1 1 0 0 -20.2 (1.39±0.02)×10−23[f]


See K(892) decay modes
D meson[33] D*+(2010) D*-(2010) Charm quarkDown antiquark 2,010.26±0.07 12 1 0 +1 0 -21.2 (7.89±0.17)×10−21[f]


D0 + Pion+ or
D+ + Pion0
D meson[34] D*0(2007) AntiD*0(2007) Charm quarkup antiquark 2,006.96±0.10 12 1 0 +1 0 -22.2 >3.1×10−22[f]


D0 + Pion0 or
D0 + Photon
Strange D meson[35] Strange D*+ Strange D*- Charm quarkstrange antiquark 2,112.1±0.4 0 1 +1 +1 0 -22.1 >3.4×10−22[f]


D*+ + Photon or
D*+ + Pion0
B meson[36] B*+ B*- up quarkbottom antiquark 5,325.2±0.4 12 1 0 0 +1 Unknown B+ + Photon
B meson[36] B*0 AntiB*0 Down quarkBottom antiquark 5,325.2±0.4 12 1 0 0 +1 Unknown B0 + Photon
Strange B meson[37] Strange B*0 Strange AntiB*0 strange quarkBottom antiquark 5,415.4+2.4
−2.1
0 1 −1 0 +1 Unknown Strange B0+Photon
Charmed B meson Charmed B*+ Charmed B*- Charm quarkbottom antiquark Unknown 0 1 0 +1 +1 Unknown Unknown

[f] ^ PDG reports the resonance width (Γ). Here the conversion τ = ​ħΓ 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:[38]

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.[38]

See also

References

  1. J.J. Aubert et al. (1974)
  2. J.E. Augustin et al. (1974)
  3. S.W. Herb et al. (1977)
  4. K.A. Olive et al. (2014): Meson Summary Table
  5. Kan Chen, et al., "Light axial vector mesons" Phys. Rev. D 91, 074025 (2015) doi: 10.1103/PhysRevD.91.074025 open access copy available at https://arxiv.org/abs/1501.07766
  6. Tanabashi, M. (2018). "Review of scalar mesons". Physical Review D 98: 030001. doi:10.1103/PhysRevD.98.030001. http://pdg.lbl.gov/2019/reviews/rpp2018-rev-scalar-mesons.pdf. 
  7. van Beveren, Eef; Rupp, George (5–10 June 2006). "Scalar and axial-vector mesons". IVth International Conference on Quarks and Nuclear Physics (QNP06) (with subsequent corrections ed.). Madrid, ES. https://arxiv.org/abs/hep-ph/0610199. 
  8. Pelaez, J.R. (2016). "From controversy to precision on the sigma meson: A review on the status of the non-ordinary [math]\displaystyle{ f_0(500) }[/math] resonance". Physics Reports 658: 1–111. doi:10.1016/j.physrep.2016.09.001. "The existence and properties of the sigma meson have been controversial for almost six decades, despite playing a central role in the spontaneous chiral symmetry of QCD or in the nucleon–nucleon attraction. This controversy has also been fed by the strong indications that it is not an ordinary quark–antiquark meson.".  Template:Access [open access copy available at Cornell U. "arXiv"]
  9. Patrignani, C. (2016). "Revised naming-scheme for hadrons". Chin. Phys. C 40: 100001.  "2017 update". http://pdg.lbl.gov/2017/reviews/rpp2017-rev-naming-scheme-hadrons.pdf. 
  10. K.A. Olive et al. (2014): Particle listings – π±
  11. K.A. Olive et al. (2014): Particle listings – π0
  12. K.A. Olive et al. (2014): Particle listings – η
  13. K.A. Olive et al. (2014): Particle listings – Error no symbol defined
  14. K.A. Olive et al. (2014): Particle listings – ηc
  15. K.A. Olive et al. (2014): Particle listings – ηb
  16. K.A. Olive et al. (2014): Particle listings – Error no symbol defined
  17. K.A. Olive et al. (2014): Particle listings – K0
  18. K.A. Olive et al. (2014): Particle listings – K0S
  19. 19.0 19.1 K.A. Olive et al. (2014): Particle listings – K0L
  20. K.A. Olive et al. (2014): Particle listings – Error no symbol defined
  21. K.A. Olive et al. (2014): Particle listings – D0
  22. K.A. Olive et al. (2014): Particle listings – Error no symbol defined
  23. K.A. Olive et al. (2014): Particle listings – Error no symbol defined
  24. K.A. Olive et al. (2014): Particle listings – B0
  25. K.A. Olive et al. (2014): Particle listings – B0s
  26. K.A. Olive et al. (2014): Particle listings – Error no symbol defined
  27. 27.0 27.1 K.A. Olive et al. (2014): Particle listings – Error no symbol defined
  28. K.A. Olive et al. (2014): Particle listings – Error no symbol defined(782)
  29. K.A. Olive et al. (2014): Particle listings – Error no symbol defined
  30. K.A. Olive et al. (2014): Particle listings – J/Ψ
  31. K.A. Olive et al. (2014): Particle listings – ϒ(1S)
  32. 32.0 32.1 K.A. Olive et al. (2014): Particle listings – K(892)
  33. K.A. Olive et al. (2014): Particle listings – Error no symbol defined(2010)
  34. K.A. Olive et al. (2014): Particle listings – Error no symbol defined(2007)
  35. K.A. Olive et al. (2014): Particle listings – Error no symbol defined
  36. 36.0 36.1 K.A. Olive et al. (2014): Particle listings – Error no symbol defined
  37. K.A. Olive et al. (2014): Particle listings – Error no symbol defined
  38. 38.0 38.1 J.W. Cronin (1980)

Bibliography

External links

it:Lista dei mesoni