List of mesons

From Freepedia

A list of mesons.

The various types of meson (not comprehensive)

Particle	Symbol	Anti- particle	Quark Makeup	Rest mass MeV/c2	S	C	B	Mean lifetime s	Notes
Charged Pion	π+	π-	<math>\mathrm{u \bar{d}}</math>	139.6	0	0	0	2.60×10-8
Neutral Pion	π0	Self	<math>\mathrm{\frac{u\bar{u} + d \bar{d}}{\sqrt{2}}}</math>	135.0	0	0	0	0.84×10-16	Makeup inexact due to non-zero quark masses
Charged Kaon	K+	K-	<math>\mathrm{u\bar{s}}</math>	493.7	+1	0	0	1.24×10-8
Neutral Kaon	<math>\mathrm{K^0}</math>	<math>\mathrm{\bar{K}^0}</math>	<math>\mathrm{d\bar{s}} </math>	497.7	+1	0	0	weak decay	Strong eigenstate - no definite lifetime (see kaon notes below)
K-Short	<math>\mathrm{K_S^0}</math>	<math>\mathrm{K_S^0}</math>	<math>\mathrm{\frac{d\bar{s} - s\bar{d}}{\sqrt{2}}} </math>	497.7	(*)	0	0	0.89×10-10	Weak eigenstate - makeup is missing small CP-violating term (see kaon notes below)
K-Long	<math>\mathrm{K_L^0}</math>	<math>\mathrm{K_L^0}</math>	<math>\mathrm{\frac{d\bar{s} + s\bar{d}}{\sqrt{2}}}</math>	497.7	(*)	0	0	5.2×10-8	Weak eigenstate - makeup is missing small CP-violating term (see kaon notes below)
Eta	η	Self	<math>\mathrm{\frac{u\bar{u} + d\bar{d} - 2s\bar{s}}{\sqrt{6}}}</math>	547.8	0	0	0	5×10-19	Makeup inexact due to non-zero quark masses
Eta Prime	η'	Self	<math>\mathrm{\frac{u\bar{u} + d\bar{d} + s\bar{s}}{\sqrt{3}}}</math>	957.6	0	0	0	3×10-21	Makeup inexact due to non-zero quark masses
Rho	ρ+	ρ-	<math>\mathrm{u\bar{d}}</math>	776	0	0	0	0.4×10-23
Phi	φ	Self	<math>\mathrm{s\bar{s}}</math>	1019	0	0	0	16×10-23
D	D+	D-	<math>\mathrm{c\bar{d}}</math>	1869	0	+1	0	10.6×10-13
D	D0	<math>\mathrm{\bar{D^0}}</math>	<math>\mathrm{c\bar{u}}</math>	1865	0	+1	0	4.1×10-13
Ds	<math>\mathrm{D_s^+}</math>	<math>\mathrm{D_s^-}</math>	<math>\mathrm{c\bar{s}}</math>	1968	+1	+1	0	4.9×10-13
J/Psi	J/ψ	Self	<math>\mathrm{c\bar{c}}</math>	3096.9	0	0	0	7.2×10-21	See charmonium
B	B+	B-	<math>\mathrm{u\bar{b}}</math>	5279	0	0	+1	1.7×10-12
B	B0	<math>\mathrm{\bar{B^0}}</math>	<math>\mathrm{d\bar{b}}</math>	5279	0	0	+1	1.5×10-12
Bs	<math>\mathrm{B_s^0}</math>	<math>\mathrm{\bar{B}_s^0}</math>	<math>\mathrm{s\bar{b}}</math>	5369	-1	0	+1	1.46×10-12
Bc	<math>\mathrm{B_c^+}</math>	<math>\mathrm{B_c^-}</math>	<math>\mathrm{c\bar{b}}</math>	6400	0	+1	+1	5×10-13
Upsilon	<math>\Upsilon\,</math>	Self	<math>\mathrm{b\bar{b}}</math>	9460	0	0	0	1.3×10-20	See bottomonium

Notes on neutral kaons

There are two complications with neutral kaons:

1. Due to neutral kaon mixing, the <math>\mathrm{K_S^0}</math> and <math>\mathrm{K_L^0}</math> are not eigenstates of strangeness. However, they are eigenstates of the weak force, which determines how they decay, so these are the particles with definite lifetime.
2. Furthermore, the linear combinations given in the table for the <math>\mathrm{K_S^0}</math> and <math>\mathrm{K_L^0}</math> are not exactly correct, since there is a small correction due to CP violation. See CP violation in kaons.

Note that these issues also exist in principle for other neutral flavored mesons; however, the weak eigenstates are considered separate particles only for kaons because of their dramatically different lifetimes.

External link

• Complete meson info from Particle Data Group

Reference

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