Mesons

Particle	Symbol	Anti- particle	Makeup	Rest mass MeV/c2	S	C	B	Lifetime	Decay Modes
Pion	π+	π-	ud	139.6	0	0	0	2.60 x10-8	μ+νμ
Pion	π0	Self		135.0	0	0	0	0.83 x10-16	2γ
Kaon	K+	K-	us	493.7	+1	0	0	1.24 x10-8	μ+νμ, π+π0
Kaon	K0s	K0s	1*	497.7	+1	0	0	0.89 x10-10	π+π-,2π0
Kaon	K0L	K0L	1*	497.7	+1	0	0	5.2 x10-8	π+e-νe
Eta	η0	Self	2*	548.8	0	0	0	<10-18	2γ, 3μ
Eta prime	η0'	Self	2*	958	0	0	0	...	π+π-η
Rho	ρ+	ρ-	ud	770	0	0	0	0.4 x10-23	π+π0
Rho	ρ0	Self	uu, dd	770	0	0	0	...	π0π0
Omega	ω0	Self	uu, dd	782	0	0	0	...	π+π-π0
Phi	φ	Self	ss	1020	0	0	0	20 x10-23	K+K-,K0K0
D	D+	D-	cd	1869.4	0	+1	0	10.6 x10-13	K + _, e + _
D	D0	D0	cu	1864.6	0	+1	0	4.2 x10-13	[K,μ,e] + _
D	D+s	D-s	cs	1969	+1	+1	0	4.7 x10-13	K + _
J/Psi	J/ψ	Self	cc	3096.9	0	0	0	0.8 x10-20	e+e-, μ+μ-...
B	B-	B+	bu	5279	0	0	-1	1.5 x10-12	D0 + _
B	B0	B0	db	5279	0	0	-1	1.5 x10-12	D0 + _
Bs	Bs0	Bs0	sb	5370	0	0	-1	...	B-s + _
Upsilon	ϒ	Self	bb	9460.4	0	0	0	1.3 x10-20	e+e-, μ+μ-..

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 K⁰_s and K⁰_L 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.