Omega baryon
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For the Star Trek particle, see Omega particle (Star Trek).
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[edit] Overview
Omega (Ω) baryons are baryons containing neither up nor down quarks of isospin I = 0. The first Omega discovered was the Ω−, made of three strange quarks. The discovery was a great triumph in the study of quark processes, since it was found only after its existence, mass, and decay products had already been predicted. Besides the Ω−, a charmed Omega particle (Ω0c) was discovered, in which a strange quark is replaced by a charm quark. The Ω− decays only via the weak interaction and has therefore a relatively long lifetime.[1] Spin (J) and parity (P) values for unobserved baryons are predicted by the quark model.[2]
[edit] Omega baryons
| Particle | Symbol | Quark content |
Rest mass MeV/c2 |
JP | Q | S | C | B | Mean lifetime s |
Decays to |
|---|---|---|---|---|---|---|---|---|---|---|
| Omega[3] | Ω− | sss | 1672.45±29 | 3⁄2+ | −1 | −3 | 0 | 0 | 8.21±0.11×10−11 | Λ0 + K− or Ξ0 + π− or |
| Charmed Omega[4] | Ω0c | ssc | 2697.5±2.6 | 1⁄2+ | 0 | −2 | +1 | 0 | 6.9±1.2×10−14 | See Ω0c Decay Modes |
| Bottom Omega† | Ω−b | ssb | 1⁄2+ | −1 | −2 | 0 | −1 | |||
| Double charmed Omega† | Ω+cc | scc | 1⁄2+ | +1 | −1 | +2 | 0 | |||
| Charmed bottom Omega† | Ω0cb | scb | 1⁄2+ | 0 | −1 | −1 | −1 | |||
| Double bottom Omega† | Ω−bb | sbb | 1⁄2+ | −1 | −1 | 0 | −2 | |||
| Triple charmed Omega† | Ω++ccc | ccc | 3⁄2+ | +2 | 0 | +3 | 0 | |||
| Double charmed bottom Omega† | Ω+ccb | ccb | 1⁄2+ | +1 | 0 | +2 | −1 | |||
| Charmed double bottom Omega† | Ω0cbb | cbb | 1⁄2+ | 0 | 0 | +1 | −2 | |||
| Triple bottom Omega† | Ω−bbb | bbb | 3⁄2+ | −1 | 0 | 0 | −3 |
† Particle (or quantity, i.e. spin) has neither been observed nor indicated.
[edit] See also
- Delta baryon
- Hyperon
- Lambda baryon
- List of mesons
- List of particles
- Nucleon
- Physics portal
- Sigma baryon
- Timeline of particle discoveries
- Xi baryon
[edit] References
- ^ The Omega Baryon
- ^ J. G. Körner, M. Krämer, and D. Pirjol (1994). "Heavy Baryons". Progress in Particle and Nuclear Physics 33: 787-868.
- ^ Particle Data Groups: 2006 Review of Particle Physics - Omega-. Retrieved on 2008-04-20.
- ^ Particle Data Groups: 2006 Review of Particle Physics - Charmed Omega0. Retrieved on 2008-04-20.
