Mesons are intermediate mass particles which are made up of a quark-antiquark pair. Three quark combinations are called baryons. Mesons are bosons, while the baryons are fermions.
1* The neutral Kaons K0s and K0L represent symmetric and antisymmetric mixtures of the quark combinations down-antistrange and antidown-strange.
2* The neutral eta meson is considered to be a quark combination
Note: In the table, antiquarks are indicated by an underline, e.g., ud means a combination of an up and an antidown quark.
Most of the listed decay times are in the range 10-13 to 10-8 s which indicates decay by the weak interaction. These decays involve quark transformations which can be represented by Feynman diagrams.
Index