Sigma baryon

Sigma Baryon
Classification
Subatomic particle Fermion, Hadron Baryon Sigma
Properties
Symbol: $\Sigma ^{+}$ $\Sigma ^{0}$ $\Sigma ^{-}$ Mass (MeV/c2): 1189.33±0.07 1192.64±0.024 1197.45±0.030 Electric Charge: +e 0 -e I(Iz), JP: 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.

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	C	B	Mean lifetime s	Decays to
Sigma	Σ+	uus	1189.4	1/2	-1	0	0	0.8×10-10	π0 + p or π+ + n
Sigma	Σ0	uds	1192.5	1/2	-1	0	0	6×10-20	Λ0 + γ
Sigma	Σ-	dds	1197.4	1/2	-1	0	0	1.5×10-10	π- + n
bottom Sigma	Σ+b	uub		1/2	0	0	-1		Λ0b + π+
bottom Sigma	Σ-b	ddb		1/2	0	0	-1		Λ0b + π-

See also

• List of baryons

References

• Particle Data Group: W.-M. Yao et al., J. Phys G 33, 1 (2006).
• The Sigma Baryon. HyperPhysics.
• "CDF finds exotic relatives of protons and neutrons". Fermilab Today. 2006-10-23