# Table of Baryons

 Particle Symbol Makeup Rest massMeV/c2 Spin B S Lifetime(seconds> Decay Modes Proton p uud 938.3 1/2 +1 0 Stable ... Neutron n ddu 939.6 1/2 +1 0 920 pe-νe Lambda Λ0 uds 1115.6 1/2 +1 -1 2.6x10-10 pπ-, nπ0 Sigma Σ+ uus 1189.4 1/2 +1 -1 0.8x10-10 pπ0, nπ+ Sigma Σ0 uds 1192.5 1/2 +1 -1 6x10-20 Λ0γ Sigma Σ- dds 1197.3 1/2 +1 -1 1.5x10-10 nπ- Delta Δ++ uuu 1232 3/2 +1 0 0.6x10-23 pπ+ Delta Δ+ uud 1232 3/2 +1 0 0.6x10-23 pπ0 Delta Δ0 udd 1232 3/2 +1 0 0.6x10-23 nπ0 Delta Δ- ddd 1232 3/2 +1 0 0.6x10-23 nπ- XiCascade Ξ0 uss 1315 1/2 +1 -2 2.9x10-10 Λ0π0 XiCascade Ξ- dss 1321 1/2 +1 -2 1.64x10-10 Λ0π- Omega Ω- sss 1672 3/2 +1 -3 0.82x10-10 Ξ0π-, Λ0K- Lambda Λ+c udc 2281 1/2 +1 0 2x10-13 ...
 To Meson Table

As an example of the notation in the column of decay modes, the sigma + decay mode is written

0, nπ+

which implies there are two common decay modes,

Σ+ → p + π0   and    Σ+ → n + π+

Particles which decay by the strong interaction typically do so on a time scale of about 10-23 seconds, and some of the baryons listed in the table above have lifetimes on the order of 10-10 seconds. The reason for those longer lifetimes is that they are forbidden by some kind of conservation law from decaying by the strong interaction, and must decay by the weak interaction. These decays involve quark transformations which can be represented by Feynman diagrams.There are dozens of other baryons (i.e., combinations of three quarks), but most of them decay by the strong interaction and are so short lived that they don't leave a measurable track in a bubble chamber or other detection device. These baryons have been detected as "resonances" or peaks in the probability for particle interactions.

### Baryon discussion

 What is a pentaquark?
Index

Particle concepts

Reference
Serway
Ch. 47

Griffiths

Particle Data Group

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