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 6975500000000000000♠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), 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

J^P = 1/2⁺ Sigma baryons
Particle name	Symbol	Quark content	Rest mass (MeV/c²)	I	J^P	Q (e)	S	C	B'	T	Mean lifetime (s)	Commonly decays to
Sigma^[4]	Σ+	u u s	1,189.37 ± 0.07	1	1/2⁺	+1	−1	0	0	0	8.018 ± 0.026 × 10⁻¹¹	p+ + π0 or n0 + π+
Sigma^[5]	Σ0	u d s	1,192.642 ± 0.024	1	1/2⁺	0	−1	0	0	0	7.4 ± 0.7 × 10⁻²⁰	Λ0 + γ
Sigma^[6]	Σ−	d d s	1,197.449 ± 0.030	1	1/2⁺	−1	−1	0	0	0	1.479 ± 0.011 × 10⁻¹⁰	n0 + π−
charmed Sigma^[7]	Σ++ c(2455)	u u c	2,454.02 ± 0.18	1	1/2 ⁺	+2	0	+1	0	0	3.0 ± 0.4 × 10⁻²²^{^[a]}	Λ+ c + π+
charmed Sigma^[7]	Σ+ c(2455)	u d c	2,452.9 ± 0.4	1	1/2 ⁺	+1	0	+1	0	0	>1.4 × 10⁻²²^{^[a]}	Λ+ c + π0
charmed Sigma^[7]	Σ0 c(2455)	d d c	2,453.76 ± 0.18	1	1/2 ⁺	0	0	+1	0	0	3.0 ± 0.5 × 10⁻²²^{^[a]}	Λ+ c + π−
bottom Sigma^[8]	Σ+ b(?^{^[b]})	u u b	5,807.8+3.7 −3.9	1	1/2 ⁺	+1	0	0	−1	0	Unknown	Λ0 b + π+ (seen)
bottom Sigma^{^†}	Σ0 b(?^{^[b]})	u d b	Unknown	1	1/2 ⁺	0	0	0	−1	0	Unknown	Unknown
bottom Sigma^[8]	Σ− b(?^{^[b]})	d d b	5,815.2 ± 2.7	1	1/2 ⁺	−1	0	0	−1	0	Unknown	Λ0 b + π− (seen)
Top Sigma^{^†}	Σ++ t	u u t	—	1	1/2 ⁺	+2	0	0	0	+1	—	—
Top Sigma^{^†}	Σ+ t	u d t	—	1	1/2 ⁺	+1	0	0	0	+1	—	—
Top Sigma^{^†}	Σ0 t	d d t	—	1	1/2 ⁺	0	0	0	0	+1	—	—

^† ^ 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

J^P = 3/2⁺ Sigma baryons
Particle name	Symbol	Quark content	Rest mass (MeV/c²)	I	J^P	Q (e)	S	C	B'	T	Mean lifetime (s)	Commonly decays to
Sigma^[9]	Σ∗+ (1385)	u u s	1,382.8 ± 0.4	1	3/2⁺	+1	−1	0	0	0	1.84 ± 0.04 × 10⁻²³^{^[c]}	Λ0 + π+ or Σ+ + π0 or Σ0 + π+
Sigma^[9]	Σ∗0 (1385)	u d s	1,383.7 ± 1.0	1	3/2⁺	0	−1	0	0	0	1.8 ± 0.3 × 10⁻²³^{^[c]}	Λ0 + π0 or Σ+ + π− or Σ0 + π0
Sigma^[9]	Σ∗− (1385)	d d s	1,387.2 ± 0.5	1	3/2⁺	−1	−1	0	0	0	1.67 ± 0.09 × 10⁻²³^{^[c]}	Λ0 + π− or Σ0 + π− or Σ− + π0 or
charmed Sigma^[10]	Σ∗++ c(2520)	u u c	2,518.4 ± 0.6	1	3/2 ⁺	+2	0	+1	0	0	4.4 ± 0.6 × 10⁻²³^{^[c]}	Λ+ c + π+
charmed Sigma^[10]	Σ∗+ c(2520)	u d c	2,517.5 ± 2.3	1	3/2 ⁺	+1	0	+1	0	0	>3.9 × 10⁻²³^{^[c]}	Λ+ c + π0
charmed Sigma^[10]	Σ∗0 c(2520)	d d c	2,518.0 ± 0.5	1	3/2 ⁺	0	0	+1	0	0	4.1 ± 0.5 × 10⁻²³^{^[c]}	Λ+ c + π−
bottom Sigma^{^†}	Σ∗+ b	u u b	Unknown	1	3/2 ⁺	+1	0	0	−1	0	Unknown	Unknown
bottom Sigma^{^†}	Σ∗0 b	u d b	Unknown	1	3/2 ⁺	0	0	0	−1	0	Unknown	Unknown
bottom Sigma^{^†}	Σ∗− b	d d b	Unknown	1	3/2 ⁺	−1	0	0	−1	0	Unknown	Unknown
Top Sigma^{^†}	Σ∗++ t	u u t	—	1	3/2 ⁺	+2	0	0	0	+1	—	—
Top Sigma^{^†}	Σ∗+ t	u d t	—	1	3/2 ⁺	+1	0	0	0	+1	—	—
Top Sigma^{^†}	Σ∗0 t	d d t	—	1	3/2 ⁺	0	0	0	0	+1	—	—

^† ^ 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.

References

↑ 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.
↑ C. Amsler et al. (2008): Particle summary tables – Baryons
↑ J. G. Körner et al. (1994)
↑ C. Amsler et al. (2008): Particle listings –
Σ+
↑ C. Amsler et al. (2008): Particle listings –
Σ0
↑ C. Amsler et al. (2008): Particle listings –
Σ−
1 2 3 C. Amsler et al. (2008): Particle listings –
Σ
c(2455)
1 2 T. Aaltonen et al. (2007a)
1 2 3 C. Amsler et al. (2008): Particle listings –
Σ
(1385)
1 2 3 C. Amsler et al. (2008): Particle listings –
Σ
c(2520)

Bibliography

C. Amsler et al. (Particle Data Group) (2008). "Review of Particle Physics". Physics Letters B. 667 (1): 1. Bibcode:2008PhLB..667....1A. doi:10.1016/j.physletb.2008.07.018.
J. G. Körner; M. Krämer & 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
Σ
b and
Σ∗
b". Physical Review Letters. 99 (20): 202001. arXiv:0706.3868. Bibcode:2007PhRvL..99t2001A. doi:10.1103/PhysRevLett.99.202001.

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Sigma baryon

List

JP = 1/2+ Sigma baryons

JP = 3/2+ Sigma baryons

See also

References

Bibliography

J^P = 1/2⁺ Sigma baryons

J^P = 3/2⁺ Sigma baryons