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Sigma (particle)

Sigma Baryon

Classification

Subatomic particle

Fermion, Hadron

Baryon

Sigma

Properties

Symbol:	$Σ +$	$Σ 0$	$Σ -$
Mass (MeV/c²):	1189.33±0.07	1192.642±0.024	1197.449±0.030
Electric Charge:	+e	0	-e
I(I_z), J^P:	1(+1), ½⁺	1(0), ½⁺	1(-1), ½⁺
Quark Composition:	uus	uds	dds

Sigma particles are baryons composed of one strange quark and a combination of up and down quarks, arranged in an isospin 1 state. These are hyperons.

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The symbol Σ is also used for similar heavier particles containing charm and bottom quarks. They are, by definition, not hyperons.

Sigma particles
Particle	Symbol	Makeup	Rest mass MeV/c²	Spin	S	B	Mean lifetime s	Decays to
Sigma	Σ⁺	uus	1189.4	1/2	-1	0	0.8×10^-10	π⁰ + p or π⁺ + n
Sigma	Σ⁰	uds	1192.5	1/2	-1	0	6×10^-20	Λ⁰ + γ
Sigma	Σ^-	dds	1197.4	1/2	-1	0	1.5×10^-10	π^- + n
bottom Sigma	Σ⁺_b	uub		1/2	0	-1		Λ⁰_b + π⁺
bottom Sigma	Σ^-_b	ddb		1/2	0	-1		Λ⁰_b + π^-

v • d • e Particles in physics
Elementary particles	Fermions: Quarks: u · d · s · c · b · t • Leptons: e^- · e⁺ · μ^- · μ⁺ · τ^- · τ⁺ · ν_e · ν_μ · ν_τ Bosons: Gauge bosons: γ · g · W^± · Z⁰ Other: Ghosts
Composite particles	Hadrons: Baryons(list)/Hyperons/Nucleons: p · n · Δ · Λ · Σ · Ξ · Ω · Ξ_b • Mesons(list)/Quarkonia: π · K · ρ · J/ψ · Υ Other: Atomic nuclei • Atoms • Exotic atoms: Positronium • Molecules
Hypothetical elementary particles	Superpartners: Axino · Dilatino · Chargino · Gluino · Gravitino · Higgsino · Neutralino · Sfermion · Slepton · Squark Other: Axion · Dilaton · Goldstone boson · Graviton · Higgs boson · Tachyon · X · Y · W' · Z'
	Exotic hadrons: Exotic baryons: Pentaquark • Exotic mesons: Glueball · Tetraquark Other: Mesonic molecule
Quasiparticles	Davydov soliton · Exciton · Magnon · Phonon · Plasmon · Polariton · Polaron