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词条 Sigma baryon
释义

  1. List

      JP = {{sfrac|1|2}}+ Sigma baryons    JP = {{sfrac|3|2}}+ Sigma baryons  

  2. See also

  3. References

  4. Bibliography

The Sigma baryons are a family of subatomic hadron particles which have two quarks from the first flavour generation (up and/or down quarks), and a third quark from higher flavour generations, in a combination where the wavefunction does not swap sign when any two quark flavours are swapped. They are thus baryons, with total Isospin of 1, and can either be neutral or have an elementary charge of +2, +1 or −1. They are closely related to the Lambda baryons, which differ only in the wavefunction's behaviour upon flavour exchange.

The third quark can hence be either a strange (symbols {{SubatomicParticle|Sigma+}}, {{SubatomicParticle|Sigma0}}, {{SubatomicParticle|Sigma-}}), a charm (symbols {{SubatomicParticle|Charmed Sigma++}}, {{SubatomicParticle|Charmed Sigma+}}, {{SubatomicParticle|Charmed Sigma0}}), a bottom (symbols {{SubatomicParticle|Bottom Sigma+}}, {{SubatomicParticle|Bottom Sigma0}}, {{SubatomicParticle|Bottom Sigma-}}) or a top (symbols {{SubatomicParticle|Top Sigma++}}, {{SubatomicParticle|Top Sigma+}}, {{SubatomicParticle|Top Sigma0}}) 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 {{val|5|e=-25|u=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 (electric 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 vice versa), 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]

JP = {{sfrac|1|2}}+ Sigma baryons

P = {{sfrac>1|2}}+ Sigma baryons
Particle name SymbolQuark
content		 Rest mass (MeV/c2)IJPQ (e)SCB'T Mean lifetime (s)Commonly decays to
Sigma[4]Sigma+}}link=yes|Up quark}}{{SubatomicParticle|link=yes|Up quark}}{{SubatomicParticle|link=yes|Strange quark}} 1,189.37 ± 0.07 11|2}}+ +1 −1 0 0 08.018 ± 0.026 × 10−11}}{{SubatomicParticle|link=yes|Proton+}} + {{SubatomicParticle|link=yes|Pion0}} or}}
{{nowrap|{{SubatomicParticle|link=yes|Neutron0}} + {{SubatomicParticle|link=yes|Pion+}}}}
Sigma[5]Sigma0}}link=yes|Up quark}}{{SubatomicParticle|link=yes|Down quark}}{{SubatomicParticle|link=yes|Strange quark}} 1,192.642 ± 0.024 11|2}}+ 0 −1 0 0 07.4 ± 0.7 × 10−20}}{{SubatomicParticle|link=yes|Lambda0}} + {{SubatomicParticle|link=yes|Photon}}}}
Sigma[6]Sigma-}}link=yes|Down quark}}{{SubatomicParticle|link=yes|Down quark}}{{SubatomicParticle|link=yes|Strange quark}} 1,197.449 ± 0.030 11|2}}+ −1 −1 0 0 01.479 ± 0.011 × 10−10}}{{SubatomicParticle|link=yes|Neutron0}} + {{SubatomicParticle|link=yes|Pion-}}}}
charmed Sigma[7]Charmed sigma++}}(2455)link=yes|Up quark}}{{SubatomicParticle|link=yes|Up quark}}{{SubatomicParticle|link=yes|Charm quark}} 2,454.02 ± 0.18 1{{sfrac>1|2}} + +2 0 +1 0 03.0 ± 0.4 × 10−22}}{{ref|Lifetime|[a]}}{{SubatomicParticle|Charmed lambda+}} + {{SubatomicParticle|link=yes|Pion+}}}}
charmed Sigma[7]Charmed sigma+}}(2455)link=yes|Up quark}}{{SubatomicParticle|link=yes|Down quark}}{{SubatomicParticle|link=yes|Charm quark}} 2,452.9 ± 0.4 1{{sfrac>1|2}} + +1 0 +1 0 0>1.4 × 10−22}}{{ref|Lifetime|[a]}}{{SubatomicParticle|Charmed lambda+}} + {{SubatomicParticle|link=yes|Pion0}}}}
charmed Sigma[7]Charmed sigma0}}(2455)link=yes|Down quark}}{{SubatomicParticle|link=yes|Down quark}}{{SubatomicParticle|link=yes|Charm quark}} 2,453.76 ± 0.18 1{{sfrac>1|2}} + 0 0 +1 0 03.0 ± 0.5 × 10−22}}{{ref|Lifetime|[a]}}{{SubatomicParticle|Charmed lambda+}} + {{SubatomicParticle|link=yes|Pion-}}}}
bottom Sigma[8]Bottom Sigma+}}link=yes|Up quark}}{{SubatomicParticle|link=yes|Up quark}}{{SubatomicParticle|link=yes|Bottom quark}} 5,807.7 ± 3.8 1{{sfrac>1|2}} + +1 0 0 −1 0 Unknown{{SubatomicParticle|link=yes|Bottom Lambda0}} + {{SubatomicParticle|link=yes|Pion+}} (seen)}}
bottom Sigma{{ref|Undiscovered|†}}Bottom Sigma0}}link=yes|Up quark}}{{SubatomicParticle|link=yes|Down quark}}{{SubatomicParticle|link=yes|Bottom quark}} Unknown 1{{sfrac>1|2}} + 0 0 0 −1 0 Unknown Unknown
bottom Sigma[8]Bottom Sigma-}}link=yes|Down quark}}{{SubatomicParticle|link=yes|Down quark}}{{SubatomicParticle|link=yes|Bottom quark}} 5,815.2 ± 2.7 1{{sfrac>1|2}} + −1 0 0 −1 0 Unknown{{SubatomicParticle|Bottom Lambda0}} + {{SubatomicParticle|link=yes|Pion-}} (seen)}}
Top Sigma{{ref|Undiscovered|†}}Top sigma++}}link=yes|Up quark}}{{SubatomicParticle|link=yes|Up quark}}{{SubatomicParticle|link=yes|Top quark}} — 1{{sfrac>1|2}} + +2 0 0 0 +1 — —
Top Sigma{{ref|Undiscovered|†}}Top sigma+}}link=yes|Up quark}}{{SubatomicParticle|link=yes|Down quark}}{{SubatomicParticle|link=yes|Top quark}} — 1{{sfrac>1|2}} + +1 0 0 0 +1 — —
Top Sigma{{ref|Undiscovered|†}}Top sigma0}}link=yes|Down quark}}{{SubatomicParticle|link=yes|Down quark}}{{SubatomicParticle|link=yes|Top quark}} — 1{{sfrac>1|2}} + 0 0 0 0 +1 — —
† {{note|Undiscovered}} The standard model predicts that this particle cannot exist due to the short lifetime of the top quark.
[a] {{note|Lifetime}} PDG reports the resonance width (Γ). Here the conversion τ = {{sfrac|ħ|Γ}} is given instead.

[b] {{note|nameofsigma}} The specific values of the name has not been decided yet, but will likely be close to {{SubatomicParticle|Bottom Sigma}}(5810).

JP = {{sfrac|3|2}}+ Sigma baryons

P = {{sfrac>3|2}}+ Sigma baryons
Particle name SymbolQuark
content		 Rest mass (MeV/c2)IJPQ (e)SCB'T Mean lifetime (s)Commonly decays to
Sigma[9]Sigma*+}}(1385)link=yes|Up quark}}{{SubatomicParticle|link=yes|Up quark}}{{SubatomicParticle|link=yes|Strange quark}} 1,382.8 ± 0.4 13|2}}+ +1 −1 0 0 01.84 ± 0.04 × 10−23}}{{ref|Lifetime2|[c]}}{{SubatomicParticle|link=yes|Lambda0}} + {{SubatomicParticle|link=yes|Pion+}} or}}
{{nowrap|{{SubatomicParticle|Sigma+}} + {{SubatomicParticle|link=yes|Pion0}} or}}
{{nowrap|{{SubatomicParticle|Sigma0}} + {{SubatomicParticle|link=yes|Pion+}}}}
Sigma[9]Sigma*0}}(1385)link=yes|Up quark}}{{SubatomicParticle|link=yes|Down quark}}{{SubatomicParticle|link=yes|Strange quark}} 1,383.7 ± 1.0 13|2}}+ 0 −1 0 0 01.8 ± 0.3 × 10−23}}{{ref|Lifetime2|[c]}}{{SubatomicParticle|link=yes|Lambda0}} + {{SubatomicParticle|link=yes|Pion0}} or}}
{{nowrap|{{SubatomicParticle|Sigma+}} + {{SubatomicParticle|link=yes|Pion-}} or}}
{{nowrap|{{SubatomicParticle|Sigma0}} + {{SubatomicParticle|link=yes|Pion0}}}}
Sigma[9]Sigma*-}}(1385)link=yes|Down quark}}{{SubatomicParticle|link=yes|Down quark}}{{SubatomicParticle|link=yes|Strange quark}} 1,387.2 ± 0.5 13|2}}+ −1 −1 0 0 01.67 ± 0.09 × 10−23}}{{ref|Lifetime2|[c]}}{{SubatomicParticle|link=yes|Lambda0}} + {{SubatomicParticle|link=yes|Pion-}} or}}
{{nowrap|{{SubatomicParticle|Sigma0}} + {{SubatomicParticle|link=yes|Pion-}} or}}
{{nowrap|{{SubatomicParticle|Sigma-}} + {{SubatomicParticle|link=yes|Pion0}} or}}
charmed Sigma[10]Charmed sigma*++}}(2520)link=yes|Up quark}}{{SubatomicParticle|link=yes|Up quark}}{{SubatomicParticle|link=yes|Charm quark}} 2,518.4 ± 0.6 1{{sfrac>3|2}} + +2 0 +1 0 04.4 ± 0.6 × 10−23}}{{ref|Lifetime2|[c]}}{{SubatomicParticle|link=yes|Charmed Lambda+}} + {{SubatomicParticle|link=yes|Pion+}}}}
charmed Sigma[10]Charmed sigma*+}}(2520)link=yes|Up quark}}{{SubatomicParticle|link=yes|Down quark}}{{SubatomicParticle|link=yes|Charm quark}} 2,517.5 ± 2.3 1{{sfrac>3|2}} + +1 0 +1 0 0>3.9 × 10−23}}{{ref|Lifetime2|[c]}}{{SubatomicParticle|link=yes|Charmed Lambda+}} + {{SubatomicParticle|link=yes|Pion0}}}}
charmed Sigma[10]Charmed sigma*0}}(2520)link=yes|Down quark}}{{SubatomicParticle|link=yes|Down quark}}{{SubatomicParticle|link=yes|Charm quark}} 2,518.0 ± 0.5 1{{sfrac>3|2}} + 0 0 +1 0 04.1 ± 0.5 × 10−23}}{{ref|Lifetime2|[c]}}{{SubatomicParticle|link=yes|Charmed Lambda+}} + {{SubatomicParticle|link=yes|Pion-}}}}
bottom Sigma{{ref|Undiscovered2|†}}Bottom Sigma*+}}link=yes|Up quark}}{{SubatomicParticle|link=yes|Up quark}}{{SubatomicParticle|link=yes|Bottom quark}} Unknown 1{{sfrac>3|2}} + +1 0 0 −1 0 Unknown Unknown
bottom Sigma{{ref|Undiscovered2|†}}Bottom Sigma*0}}link=yes|Up quark}}{{SubatomicParticle|link=yes|Down quark}}{{SubatomicParticle|link=yes|Bottom quark}} Unknown 1{{sfrac>3|2}} + 0 0 0 −1 0 Unknown Unknown
bottom Sigma{{ref|Undiscovered2|†}}Bottom Sigma*-}}link=yes|Down quark}}{{SubatomicParticle|link=yes|Down quark}}{{SubatomicParticle|link=yes|Bottom quark}} Unknown 1{{sfrac>3|2}} + −1 0 0 −1 0 Unknown Unknown
Top Sigma{{ref|Undiscovered2|†}}Top sigma*++}}link=yes|Up quark}}{{SubatomicParticle|link=yes|Up quark}}{{SubatomicParticle|link=yes|Top quark}} — 1{{sfrac>3|2}} + +2 0 0 0 +1 — —
Top Sigma{{ref|Undiscovered2|†}}Top sigma*+}}link=yes|Up quark}}{{SubatomicParticle|link=yes|Down quark}}{{SubatomicParticle|link=yes|Top quark}} — 1{{sfrac>3|2}} + +1 0 0 0 +1 — —
Top Sigma{{ref|Undiscovered2|†}}Top sigma*0}}link=yes|Down quark}}{{SubatomicParticle|link=yes|Down quark}}{{SubatomicParticle|link=yes|Top quark}} — 1{{sfrac>3|2}} + 0 0 0 0 +1 — —
† {{note|Undiscovered2}} The standard model predicts that this particle cannot exist due to the short lifetime of the top quark.

[c] {{note|Lifetime2}} PDG reports the resonance width (Γ). Here the conversion τ = {{sfrac|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. ^{{cite journal |author=A. Quadt |year=2006 |title=Top quark physics at hadron colliders |journal=European Physical Journal C |volume=48 |issue=3 |pages=835–1000 |doi=10.1140/epjc/s2006-02631-6|bibcode = 2006EPJC...48..835Q }}
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 – {{SubatomicParticle|Sigma+}}
5. ^C. Amsler et al. (2008): Particle listings – {{SubatomicParticle|Sigma0}}
6. ^C. Amsler et al. (2008): Particle listings – {{SubatomicParticle|Sigma-}}
7. ^1 2 C. Amsler et al. (2008): Particle listings – {{SubatomicParticle|Charmed Sigma}}(2455)
8. ^1 T. Aaltonen et al. (2007a)
9. ^1 2 C. Amsler et al. (2008): Particle listings – {{SubatomicParticle|Sigma}}(1385)
10. ^1 2 C. Amsler et al. (2008): Particle listings – {{SubatomicParticle|Charmed Sigma}}(2520)

Bibliography

  • {{cite journal |author=C. Amsler et al. (Particle Data Group) |title=Review of Particle Physics |journal=Physics Letters B |volume=667 |issue=1 |pages= 1|year=2008 | doi=10.1016/j.physletb.2008.07.018|bibcode = 2008PhLB..667....1A }}
  • {{cite journal |author1=J. G. Körner |author2=M. Krämer |author3=D. Pirjol |last-author-amp=yes |title=Heavy Baryons |journal=Progress in Particle and Nuclear Physics |volume=33 |year=1994|pages=787–868 | id= |doi=10.1016/0146-6410(94)90053-1 |arxiv=hep-ph/9406359|bibcode = 1994PrPNP..33..787K }}
  • {{cite journal |author=T. Aaltonen et al. (CDF Collaboration) |title=First Observation of Heavy Baryons {{SubatomicParticle|Bottom Sigma}} and {{SubatomicParticle|Bottom Sigma}} |journal=Physical Review Letters |volume=99 | pages=202001 | year=2007a |id= | doi=10.1103/PhysRevLett.99.202001 | arxiv=0706.3868 | bibcode=2007PhRvL..99t2001A |issue=20|url=https://digital.csic.es/bitstream/10261/8529/2/e202001.pdf }}
{{Particles}}{{DEFAULTSORT:Sigma Baryon}}

1 : Baryons
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