Table of Baryons

ParticleSymbolMakeupRest mass
MeV/c2
SpinBS
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
2.6
x10-10
-, nπ0
Sigma
Σ+
uus
1189.4
1/2
+1
-1
0.8
x10-10
0, nπ+
Sigma
Σ0
uds
1192.5
1/2
+1
-1
6x10-20
Λ0γ
Sigma
Σ-
dds
1197.3
1/2
+1
-1
1.5
x10-10
-
Delta
Δ++
uuu
1232
3/2
+1
0
0.6
x10-23
+
Delta
Δ+
uud
1232
3/2
+1
0
0.6
x10-23
0
Delta
Δ0
udd
1232
3/2
+1
0
0.6
x10-23
0
Delta
Δ-
ddd
1232
3/2
+1
0
0.6
x10-23
-
Xi
Cascade
Ξ0
uss
1315
1/2
+1
-2
2.9
x10-10
Λ0π0
Xi
Cascade
Ξ-
dss
1321
1/2
+1
-2
1.64
x10-10
Λ0π-
Omega
Ω-
sss
1672
3/2
+1
-3
0.82
x10-10
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 diagram

Baryon discussion

What is a pentaquark?
Index

Particle concepts

Reference
Serway
Ch. 47

Griffiths


Particle Data Group
 
HyperPhysics***** Quantum Physics R Nave
Go Back