Sigma baryon

The Sigma baryons are a family of subatomic hadron particles which have a +2, +1 or -1 elementary charge or are neutral. They are baryons containing three quarks: two up and/or down quarks, and one third quark, which can be either a strange (symbols Σ+
, Σ0
, Σ−
), a charm (symbols Σ++
c, Σ+
c, Σ0
c), a bottom (symbols Σ+
b, Σ0
b, Σ−
b) or a top (symbols Σ++
t, Σ+
t, Σ0
t) quark. However, the top Sigmas are not expected to be observed as the Standard Model predicts the mean lifetime of top quarks to be roughly 5×10⁻²⁵ s.^[1] This is about 20 times shorter than the timescale for strong interactions, and therefore it does not form hadrons.

List

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), t (top quark), b (bottom quark), Q (charge), B (baryon number), S (strangeness), C (charmness), B′ (bottomness), T (topness), as well as other subatomic particles (hover for name).

Antiparticles are not listed in the table; however, they simply would have all quarks changed to antiquarks, and Q, B, S, C, B′, T, would be of opposite signs. I, J, and P values in red have not been firmly established by experiments, but are predicted by the quark model and are consistent with the measurements.^[2][3]

J^P = ¹⁄₂⁺ Sigma baryons

^† ^ Particle currently unobserved, but predicted by the standard model.
^[a] ^ PDG reports the resonance width (Γ). Here the conversion τ = ^ħ⁄_Γ is given instead.
^[b] ^ The specific values of the name has not been decided yet, but will likely be close to Σ
b(5810).

J^P = ³⁄₂⁺ Sigma baryons

^† ^ Particle currently unobserved, but predicted by the standard model.
^[c] ^ PDG reports the resonance width (Γ). Here the conversion τ = ^ħ⁄_Γ is given instead.

See also

• Delta baryon
• Hyperon
• Lambda baryon
• List of mesons
• List of particles
• Nucleon
• Omega baryon
• Physics portal
• Timeline of particle discoveries
• Xi baryon

References

1. ^ A. Quadt (2006). "Top quark physics at hadron colliders". European Physical Journal C 48 (3): 835–1000. Bibcode 2006EPJC...48..835Q. doi:10.1140/epjc/s2006-02631-6. 
2. ^ C. Amsler et al. (2008): Particle summary tables - Baryons
3. ^ J. G. Körner et al. (1994)
4. ^ C. Amsler et al. (2008): Particle listings – Error no symbol defined
5. ^ C. Amsler et al. (2008): Particle listings – Error no symbol defined
6. ^ C. Amsler et al. (2008): Particle listings – Error no symbol defined
7. ^ ^{a b c} C. Amsler et al. (2008): Particle listings – Error no symbol defined(2455)
8. ^ ^{a b} T. Aaltonen et al. (2007a)
9. ^ ^{a b c} C. Amsler et al. (2008): Particle listings – Error no symbol defined(1385)
10. ^ ^{a b c} C. Amsler et al. (2008): Particle listings – Error no symbol defined(2520)

Bibliography

• C. Amsler et al. (Particle Data Group) (2008). "Review of Particle Physics". Physics Letters B 667 (1): 1. Bibcode 2008PhLB..667....1P. doi:10.1016/j.physletb.2008.07.018. 
• J. G. Körner, M. Krämer, and D. Pirjol (1994). "Heavy Baryons". Progress in Particle and Nuclear Physics 33: 787–868. arXiv:hep-ph/9406359. Bibcode 1994PrPNP..33..787K. doi:10.1016/0146-6410(94)90053-1. 
• T. Aaltonen et al. (CDF Collaboration) (2007a). "First Observation of Heavy Baryons Error no symbol defined and Error no symbol defined". Physical Review Letters 99 (20): 202001. arXiv:0706.3868. Bibcode 2007PhRvL..99t2001A. doi:10.1103/PhysRevLett.99.202001.