List of baryons

This list is of all known and predicted baryons. See list of particles for a more detailed list of particles found in particle physics.

Baryons are the family of composite particle made of three quarks, as opposed to the mesons which are the family of composite particles made of one quark and one antiquark. Both baryons and mesons are part of the larger particle family comprising all particles made of quarks – the hadron. The term baryon is derived from the Greek βαρύς (barys), meaning "heavy", because at the time of their naming it was believed that baryons were characterized by having greater masses than other particles.

Until very recently, it was believed that some experiments showed the existence of pentaquarks – "exotic" baryons made of four quarks and one antiquark.[1][2] The particle physics community as a whole did not view their existence as likely in 2006,[3] and in 2008, considered evidence to be overwhelmingly against the existence of the reported pentaquarks.[4]

Since baryons are composed of quarks, they participate in the strong interaction. Leptons on the other hands, are not composed of quarks and as such do not participate in the strong interaction. The most famous baryons are the protons and neutrons which make up most of the mass of the visible matter in the universe, whereas electrons (the other major component of atoms) are leptons. Each baryon has a corresponding antiparticle (antibaryon) where quarks are replaced by their corresponding antiquarks. For example, a proton is made of two up quarks and one down quark; and its corresponding antiparticle, the antiproton, is made of two up antiquarks and one down antiquark.

Contents

Lists of baryons

These lists detail all known and predicted baryons in total angular momentum J = 1⁄2 and J = 3⁄2 configurations with positive parity.

The symbols encountered in these lists are: I (isospin), J (total angular momentum), P (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), B′ (bottomness), as well as a wide array of subatomic particles (hover for name). (See the baryon article for a detailed explanation of these symbols.)

Antiparticles are not listed in the tables; however, they simply would have all quarks changed to antiquarks (and antiquarks changed to quarks), and Q, B, S, C, B′, would be of opposite signs. 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.[5][6]

JP = 1⁄2+ baryons

JP = 1⁄2+ baryons
Particle name Symbol Quark
content		 Rest mass (MeV/c2) I JP Q (e) S C B' Mean lifetime (s) Commonly decays to
nucleon/proton[7] p / p+ / N+ uud 938.272029±0.000080[a] 1⁄2 1⁄2+ +1 0 0 0 Stable[b] Unobserved
nucleon/neutron[8] n / n0 / N0 udd 939.565360±0.000081[a] 1⁄2 1⁄2+ 0 0 0 0 8.857±0.008×102[c] p+ + e− + νe
Lambda[9] Λ0 uds 1,115.683±0.006 0 1⁄2+ 0 −1 0 0 2.631±0.020×10−10 p+ + π− or
n0 + π0
charmed Lambda[10] Λ+c udc 2,286.46±0.14 0 1⁄2+ +1 0 +1 0 2.00±0.06×10−13 See Λ+c decay modes
bottom Lambda[11] Λ0b udb 5,620.2±1.6 0 1⁄2+ 0 0 0 −1 1.409+0.055−0.054×10−12 See Λ0b decay modes
Sigma[12] Σ+ uus 1,189.37±0.07 1 1⁄2+ +1 −1 0 0 8.018±0.026×10−11 p+ + π0 or

n0 + π+
Sigma[13] Σ0 uds 1,192.642±0.024 1 1⁄2+ 0 −1 0 0 7.4±0.7×10−20 Λ0 + γ
Sigma[14] Σ− dds 1,197.449±0.030 1 1⁄2+ −1 −1 0 0 1.479±0.011×10−10 n0 + π−
charmed Sigma[15] Σ++c(2455) uuc 2,454.02±0.18 1 1⁄2+ +2 0 +1 0 3.0±0.4×10−22[d] Λ+c + π+
charmed Sigma[15] Σ+c(2455) udc 2,452.9±0.4 1 1⁄2+ +1 0 +1 0 >1.4×10−22[d] Λ+c + π0
charmed Sigma[15] Σ0c(2455) ddc 2,453.76±0.18 1 1⁄2+ 0 0 +1 0 3.0±0.5×10−22[d] Λ+c + π−
bottom Sigma[16] Σ+b(?[e]) uub 5,807.8±2.7 1 1⁄2+ +1 0 0 −1 Unknown Λ0b + π+
bottom Sigma† Σ0b(?[e]) udb Unknown 1 1⁄2+ 0 0 0 −1 Unknown Unknown
bottom Sigma[16] Σ−b(?[e]) ddb 5,815.2±2.0 1 1⁄2+ −1 0 0 −1 Unknown Λ0b + π−
Xi[17] Ξ0 uss 1,314.86±0.20 1⁄2 1⁄2+ 0 −2 0 0 2.90±0.09×10−10 Λ0 + π0
Xi[18] Ξ− dss 1,321.71±0.07 1⁄2 1⁄2+ −1 −2 0 0 1.639±0.015×10−10 Λ0 + π−
charmed Xi[19] Ξ+c usc 2,467.9±0.4 1⁄2 1⁄2+ +1 −1 +1 0 4.42±0.26×10−13 See Ξ+c decay modes
charmed Xi[20] Ξ0c dsc 2,471.0±0.4 1⁄2 1⁄2+ 0 −1 +1 0 1.12+0.13−0.10×10−13 See Ξ0c decay modes
charmed Xi prime[21] Ξ′+c usc 2,575.7±3.1 1⁄2 1⁄2+ +1 −1 +1 0 Unknown Ξ+c + γ (seen)
charmed Xi prime[22] Ξ′0c dsc 2,578.0±2.9 1⁄2 1⁄2+ 0 −1 +1 0 Unknown Ξ0c + γ (seen)
double charmed Xi[f]† Ξ++cc ucc Unknown 1⁄2 1⁄2+ +2 0 +2 0 Unknown Unknown
double charmed Xi[f][23] Ξ+cc dcc 3,518.9±0.9[f] 1⁄2 1⁄2+ +1 0 +2 0 <3.3×10−14[f] Λ+c + K− + π+[f] or
p+ + D+ + K−[f]
bottom Xi[24]
(or Cascade B)		 Ξ0b usb Unknown 1⁄2 1⁄2+ 0 −1 0 −1 1.42+0.28−0.24×10−12[g] See Ξb decay modes
bottom Xi[24]
(or Cascade B)		 Ξ−b dsb 5,792.4±3.0 1⁄2 1⁄2+ −1 −1 0 −1 1.42+0.28−0.24×10−12[g] See Ξb decay modes
(Ξ− + J/ψ was also seen)
bottom Xi prime† Ξ′0b usb Unknown 0 1⁄2+ 0 −1 0 −1 Unknown Unknown
bottom Xi prime† Ξ′−b dsb Unknown 0 1⁄2+ −1 −1 0 −1 Unknown Unknown
double bottom Xi† Ξ0bb ubb Unknown 1⁄2 1⁄2+ 0 0 0 −2 Unknown Unknown
double bottom Xi† Ξ−bb dbb Unknown 1⁄2 1⁄2+ −1 0 0 −2 Unknown Unknown
charmed bottom Xi† Ξ+cb ucb Unknown 1⁄2 1⁄2+ +1 0 +1 −1 Unknown Unknown
charmed bottom Xi† Ξ0cb dcb Unknown 1⁄2 1⁄2+ 0 0 +1 −1 Unknown Unknown
charmed bottom Xi prime† Ξ′+cb ucb Unknown 0 1⁄2+ +1 0 +1 −1 Unknown Unknown
charmed bottom Xi prime† Ξ′0cb dcb Unknown 0 1⁄2+ +1 0 +1 −1 Unknown Unknown
charmed Omega[25] Ω0c ssc 2,697.5±2.6 0 1⁄2+ 0 −2 +1 0 6.9±1.2×10−14 See Ω0c decay modes
bottom Omega[26] Ω−b ssb 6,165±23 0 1⁄2+ −1 −2 0 −1 1.13+0.55−0.42×10−12 (Ω− + J/ψ seen)
double charmed Omega† Ω+cc scc Unknown 0 1⁄2+ +1 −1 +2 0 Unknown Unknown
charmed bottom Omega† Ω0cb scb Unknown 0 1⁄2+ 0 −1 +1 −1 Unknown Unknown
charmed bottom Omega prime† Ω′0cb scb Unknown 0 1⁄2+ 0 −1 +1 −1 Unknown Unknown
double bottom Omega† Ω−bb sbb Unknown 0 1⁄2+ −1 −1 0 −2 Unknown Unknown
double charmed bottom Omega† Ω+ccb ccb Unknown 0 1⁄2+ +1 0 +2 −1 Unknown Unknown
charmed double bottom Omega† Ω0cbb cbb Unknown 0 1⁄2+ 0 0 +1 −2 Unknown Unknown

†^ Particle has not yet been observed.
[a] ^ The masses of the proton and neutron are known with much better precision in atomic mass units (u) than in MeV/c2, due to the relatively poorly known value of the elementary charge. In atomic mass unit, the mass of the proton is 1.007 276 466 88(13) u while that of the neutron is 1.008 664 915 60(55) u.
[b] ^ At least 1035 years. See proton decay.
[c] ^ For free neutrons; in most common nuclei, neutrons are stable.
[d] ^ PDG reports the resonance width (Γ). Here the conversion τ = ħ⁄Γ is given instead.
[e] ^ The specific values of the name has not been decided yet, but will likely be close to Σb(5810).
[f] ^ Some controversy exists about this data.[23]
[g] ^ This is actually a measurement of the average lifetime of b-baryons that decay to a jet containing a same sign Ξ∓l∓ pair. Presumably the mix is mainly Ξb, with some Λb.

JP = 3⁄2+ baryons

JP = 3⁄2+ baryons
Particle name Symbol Quark
content		 Rest mass (MeV/c2) I JP Q (e) S C B' Mean lifetime (s) Commonly decays to
Delta[27] Δ++(1232) uuu 1,232±1 3⁄2 3⁄2+ +2 0 0 0 5.58±0.09×10−24[h] p+ + π+
Delta[27] Δ+(1232) uud 1,232±1 3⁄2 3⁄2+ +1 0 0 0 5.58±0.09×10−24[h] π+ + n0 or

π0 + p+
Delta[27] Δ0(1232) udd 1,232±1 3⁄2 3⁄2+ 0 0 0 0 5.58±0.09×10−24[h] π0 + n0 or

π− + p+
Delta[27] Δ−(1232) ddd 1,232±1 3⁄2 3⁄2+ −1 0 0 0 5.58±0.09×10−24[h] π− + n0
Sigma[28] Σ∗+(1385) uus 1,382.8±0.4 1 3⁄2+ +1 −1 0 0 1.84±0.04×10−23[h] Λ0 + π+ or

Σ+ + π0 or
Σ0 + π+
Sigma[28] Σ∗0(1385) uds 1,383.7±1.0 1 3⁄2+ 0 −1 0 0 1.8±0.3×10−23[h] Λ0 + π0 or

Σ+ + π− or
Σ0 + π0
Sigma[28] Σ∗−(1385) dds 1,387.2±0.5 1 3⁄2+ −1 −1 0 0 1.67±0.09×10−23[h] Λ0 + π− or

Σ0 + π− or
Σ− + π0 or
charmed Sigma[29] Σ∗++c(2520) uuc 2,518.4±0.6 1 3⁄2 + +2 0 +1 0 4.4±0.6×10−23[h] Λ+c + π+
charmed Sigma[29] Σ∗+c(2520) udc 2,517.5±2.3 1 3⁄2 + +1 0 +1 0 >3.9×10−23[h] Λ+c + π0
charmed Sigma[29] Σ∗0c(2520) ddc 2,518.0±0.5 1 3⁄2 + 0 0 +1 0 4.1±0.5×10−23[h] Λ+c + π−
bottom Sigma[30] Σ∗+b uub 5,829.0±3.4 1 3⁄2 + +1 0 0 −1 Unknown Λ0b + π+
bottom Sigma† Σ∗0b udb Unknown 1 3⁄2 + 0 0 0 −1 Unknown Unknown
bottom Sigma[30] Σ∗−b ddb 5,836.4±2.8 1 3⁄2 + −1 0 0 −1 Unknown Λ0b + π−
Xi[31] Ξ∗0(1530) uss 1,531.80±0.32 1⁄2 3⁄2+ 0 −2 0 0 7.2±0.4×10−23[h] Ξ0 + π0 or

Ξ− + π+
Xi[31] Ξ∗−(1530) dss 1,535.0±0.6 1⁄2 3⁄2+ −1 −2 0 0 6.7+1.1−1.2×10−23[h] Ξ0 + π− or

Ξ− + π0
charmed Xi[32] Ξ∗+c(2645) usc 2,646.6±1.4 1⁄2 3⁄2 + +1 −1 +1 0 >2.1×10−22[h] Ξ+c + π0 (seen)
charmed Xi[32] Ξ∗0c(2645) dsc 2,646.1±1.2 1⁄2 3⁄2 + 0 −1 +1 0 >1.2×10−22[h] Ξ+c + π− (seen)
double charmed Xi† Ξ∗++cc ucc Unknown 1⁄2 3⁄2 + +2 0 +2 0 Unknown Unknown
double charmed Xi† Ξ∗+cc dcc Unknown 1⁄2 3⁄2 + +1 0 +2 0 Unknown Unknown
bottom Xi† Ξ∗0b usb Unknown 1⁄2 3⁄2 + 0 −1 0 −1 Unknown Unknown
bottom Xi† Ξ∗−b dsb Unknown 1⁄2 3⁄2 + −1 −1 0 −1 Unknown Unknown
double bottom Xi† Ξ∗0bb ubb Unknown 1⁄2 3⁄2 + 0 0 0 −2 Unknown Unknown
double bottom Xi† Ξ∗−bb dbb Unknown 1⁄2 3⁄2 + −1 0 0 −2 Unknown Unknown
charmed bottom Xi† Ξ∗+cb ucb Unknown 1⁄2 3⁄2 + +1 0 +1 −1 Unknown Unknown
charmed bottom Xi† Ξ∗0cb dcb Unknown 1⁄2 3⁄2 + 0 0 +1 −1 Unknown Unknown
Omega[33] Ω− sss 1,672.45±0.29 0 3⁄2+ −1 −3 0 0 8.21±0.11×10−11[h] Λ0 + K− or
Ξ0 + π− or

Ξ− + π0
charmed Omega[34] Ω∗0c(2770) ssc 2,768.3±1.5 0 3⁄2 + 0 −2 +1 0 Unknown Ω0c + γ
bottom Omega† Ω∗−b ssb Unknown 0 3⁄2 + −1 −2 0 −1 Unknown Unknown
double charmed Omega† Ω∗+cc scc Unknown 0 3⁄2 + +1 −1 +2 0 Unknown Unknown
charmed bottom Omega† Ω∗0cb scb Unknown 0 3⁄2 + 0 −1 +1 −1 Unknown Unknown
double bottom Omega† Ω∗−bb sbb Unknown 0 3⁄2 + −1 −1 0 −2 Unknown Unknown
triple charmed Omega† Ω++ccc ccc Unknown 0 3⁄2 + +2 0 +3 0 Unknown Unknown
double charmed bottom Omega† Ω∗+ccb ccb Unknown 0 3⁄2 + +1 0 +2 −1 Unknown Unknown
charmed double bottom Omega† Ω∗0cbb cbb Unknown 0 3⁄2 + 0 0 +1 −2 Unknown Unknown
triple bottom Omega† Ω−bbb bbb Unknown 0 3⁄2 + −1 0 0 −3 Unknown Unknown

†^ Particle has not yet been observed.
[h] ^ PDG reports the resonance width (Γ). Here the conversion τ = ħ⁄Γ is given instead.

See also


References

  1. ↑ H. Muir (2003)
  2. ↑ K. Carter (2003)
  3. ↑ W.-M. Yao et al. (2006): Particle listings – Positive Theta
  4. ↑ C. Amsler et al. (2008): Pentaquarks
  5. ↑ C. Amsler et al. (2008): Particle summary tables – Baryons
  6. ↑ J.G. Körner et al. (1994)
  7. ↑ C. Amsler et al. (2008): Particle listings – p+
  8. ↑ C. Amsler et al. (2008): Particle listings – n0
  9. ↑ C. Amsler et al. (2008): Particle listings – Λ
  10. ↑ C. Amsler et al. (2008): Particle listings – Λc
  11. ↑ C. Amsler et al. (2008): Particle listings – Λb
  12. ↑ C. Amsler et al. (2008): Particle listings – Σ+
  13. ↑ C. Amsler et al. (2008): Particle listings – Σ0
  14. ↑ C. Amsler et al. (2008): Particle listings – Σ−
  15. ↑ 15.0 15.1 15.2 C. Amsler et al. (2008): Particle listings – Σc(2455)
  16. ↑ 16.0 16.1 C. Amsler et al. (2008): Particle listings – Σb
  17. ↑ C. Amsler et al. (2008): Particle listings – Ξ0
  18. ↑ C. Amsler et al. (2008): Particle listings – Ξ−
  19. ↑ C. Amsler et al. (2008): Particle listings – Ξ+c
  20. ↑ C. Amsler et al. (2008): Particle listings – Ξ0c
  21. ↑ C. Amsler et al. (2008): Particle listings – Ξ′+c
  22. ↑ C. Amsler et al. (2008): Particle listings – Ξ′0c
  23. ↑ 23.0 23.1 C. Amsler et al. (2008): Particle listings – Ξ++cc
  24. ↑ 24.0 24.1 C. Amsler et al. (2008): Particle listings – Ξb
  25. ↑ C. Amsler et al. (2008): Particle listings – Ω0c
  26. ↑ C. Amsler et al. (2008): Particle listings – Ω−b
  27. ↑ 27.0 27.1 27.2 27.3 C. Amsler et al. (2008): Particle listings – Δ(1232)
  28. ↑ 28.0 28.1 28.2 C. Amsler et al. (2008): Particle listings – Σ(1385)
  29. ↑ 29.0 29.1 29.2 C. Amsler et al. (2008): Particle listings – Σc(2520)
  30. ↑ 30.0 30.1 C. Amsler et al. (2008): Particle listings – Σ∗b
  31. ↑ 31.0 31.1 C. Amsler et al. (2008): Particle listings – Ξ(1530)
  32. ↑ 32.0 32.1 C. Amsler et al. (2008): Particle listings – Ξc(2645)
  33. ↑ C. Amsler et al. (2008): Particle listings – Ω−
  34. ↑ C. Amsler et al. (2008): Particle listings – Ω0c(2770)

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