Mesons

K0
 
K+
 
π
 
π0
 
π+
 
K
 
K0
 
D+
s
D0
 
D+
 
D
 
D0
 
D
s
B0
s
B
 
B0
 
B
c
B0
 
B+
 
B0
s
B+
c
η
η
η 
c
η 
b
K0
S
K0
L
pseudo-
scalar
(spin-0)
mesons
vector
(spin-1)
mesons
(anti)
quarks
in
mesons
mass
spin
charge
isospin
strangeness
charm
bottomness
topness
what's the pattern?
what about the bottom row?
what's missing?
what's the significance of spin?
pseudoscalar (spin-0) mesons
each of the mesons on this page is made up of a spin-1/2 quark and a spin-1/2 antiquark whose spins combine to give a total angular momentum of zero

Notes

This representation of 52 mesons shows some of the weirder particles in the universe

Mesons are particles made up of one quark and one antiquark. None of the mesons forms part of our common picture of the atom, though the pion, Kaon and J/ψ are involved in the strong force between protons and neutrons in the nucleus.

The mesons shown represent every possible combination of down, up, strange, charm and bottom quarks and antiquarks (though some mesons represent superpositions of such combinations). Mesons that contain top quarks are not shown, because these have such high mass that it is difficult to create them in particle accelerators.

Every inch of this visualization is active. Move your mouse over a meson to show its name, properties and further information. Move your mouse over a page tab to show more mesons, or which quarks and antiquarks comprise each meson. Or move your mouse over a property to show the value of that property for each of the mesons. Click on a control to hold it down, then click elsewhere to release it.

Comments

Guy Pitman ⋅ 27 June 2014

VERY NICE-
The Isospin is not right though!

Mark Jeffery ⋅ 27 June 2014

Thanks for challenging the isospins, Guy! I took these values from the Wikipedia – List of mesons article. I've just double-checked, and my isospins match those in the article. So if these values are wrong, maybe you could edit the Wikipedia article to correct it? If the Wikipedia community agrees, I'll update this presentation accordingly. I appreciate your diligence!

More

This is one of a series of visualizations of what things are made of, from elementary particles to organic molecules…

Elementary Particles

Mesons – this page

Baryons

Nuclides

Atoms

…check back soon for the next in the series

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Text

A text summary of this presentation is shown below for easy reference

Particles

up quark   

charm quark   

top quark   

up antiquark   

charm antiquark   

top antiquark   

down quark   

strange quark   

bottom quark   

down antiquark   

strange antiquark   

bottom antiquark   

Kaon   K0
 

this Kaon consists of a down quark and a strange antiquark (d and s)

Kaon   K+
 

this Kaon consists of an up quark and a strange antiquark (u and s)

pion   π
 

this pion consists of a down quark and an up antiquark (d and u)

pion   π0
 

this pion is a superposition of an up quark and antiquark (u and u) and a down quark and antiquark (d and d)

pion   π+
 

this pion consists of an up quark and a down antiquark (u and d)

Kaon   K
 

this Kaon consists of a strange quark and an up antiquark (s and u)

Kaon   K0
 

this Kaon consists of a strange quark and a down antiquark (s and d)

strange D meson   D+
s

this strange D meson consists of a charm quark and a strange antiquark (c and s)

D meson   D0
 

this D meson consists of a charm quark and an up antiquark (c and u)

D meson   D+
 

this D meson consists of a charm quark and a down antiquark (c and d)

D meson   D
 

this D meson consists of a down quark and a charm antiquark (d and c)

D meson   D0
 

this D meson consists of an up quark and a charm antiquark (u and c)

strange D meson   D
s

this strange D meson consists of a strange quark and a charm antiquark (s and c)

strange B meson   B0
s

this strange B meson consists of a bottom quark and a strange antiquark (b and s)

B meson   B
 

this B meson consists of a bottom quark and an up antiquark (b and u)

B meson   B0
 

this B meson consists of a bottom quark and a down antiquark (b and d)

charmed B meson   B
c

this charmed B meson consists of a bottom quark and a charm antiquark (b and c)

B meson   B0
 

this B meson consists of a down quark and a bottom antiquark (d and b)

B meson   B+
 

this B meson consists of an up quark and a bottom antiquark (u and b)

strange B meson   B0
s

this strange B meson consists of a strange quark and a bottom antiquark (s and b)

charmed B meson   B+
c

this charmed B meson consists of a charm quark and a bottom antiquark (c and b)

eta meson   η

this eta meson is a superposition of an up quark and antiquark (u and u), a down quark and antiquark (d and d) and a strange quark and antiquark (s and s)

eta prime meson   η

this eta prime meson is a superposition of an up quark and antiquark (u and u), a down quark and antiquark (d and d) and a strange quark and antiquark (s and s)

charmed eta meson   η 
c

this charmed eta meson consists of a charm quark and a charm antiquark (c and c)

bottom eta meson   η 
b

this bottom eta meson consists of a bottom quark and a bottom antiquark (b and b)

K-Short   K0
S

this K-Short is a superposition of a down quark and strange antiquark (d and s) and a strange quark and down antiquark (s and d)

K-Long   K0
L

this K-Long is a superposition of a down quark and strange antiquark (d and s) and a strange quark and down antiquark (s and d)

Kaon   K0
 

this Kaon consists of a down quark and a strange antiquark (d and s)

Kaon   K+
 

this Kaon consists of an up quark and a strange antiquark (u and s)

charged rho meson   ρ
 

this charged rho meson consists of a down quark and an up antiquark (d and u)

neutral rho meson   ρ0
 

this neutral rho meson is a superposition of an up quark and antiquark (u and u) and a down quark and antiquark (d and d)

charged rho meson   ρ+
 

this charged rho meson consists of an up quark and a down antiquark (u and d)

Kaon   K
 

this Kaon consists of a strange quark and an up antiquark (s and u)

Kaon   K0
 

this Kaon consists of a strange quark and a down antiquark (s and d)

strange D meson   D+
s

this strange D meson consists of a charm quark and a strange antiquark (c and s)

D meson   D0
 

this D meson consists of a charm quark and an up antiquark (c and u)

D meson   D+
 

this D meson consists of a charm quark and a down antiquark (c and d)

D meson   D
 

this D meson consists of a down quark and a charm antiquark (d and c)

D meson   D0
 

this D meson consists of an up quark and a charm antiquark (u and c)

strange D meson   D
s

this strange D meson consists of a strange quark and a charm antiquark (s and c)

strange B meson   B0
s

this strange B meson consists of a bottom quark and a strange antiquark (b and s)

B meson   B
 

this B meson consists of a bottom quark and an up antiquark (b and u)

B meson   B0
 

this B meson consists of a bottom quark and a down antiquark (b and d)

charmed B meson   B
c

this charmed B meson consists of a bottom quark and a charm antiquark (b and c)

B meson   B0
 

this B meson consists of a down quark and a bottom antiquark (d and b)

B meson   B+
 

this B meson consists of an up quark and a bottom antiquark (u and b)

strange B meson   B0
s

this strange B meson consists of a strange quark and a bottom antiquark (s and b)

charmed B meson   B+
c

this charmed B meson consists of a charm quark and a bottom antiquark (c and b)

omega meson   ω

this omega meson is a superposition of an up quark and antiquark (u and u) and a down quark and antiquark (d and d)

phi meson   φ

this phi meson consists of a strange quark and a strange antiquark (s and s)

J/psi   J/ψ

this J/psi consists of a charm quark and a charm antiquark (c and c)

Upsilon meson   Υ

this Upsilon meson consists of a bottom quark and a bottom antiquark (b and b)

Information

what's the pattern?

the mesons are arranged according to flavours of their constituent quarks and antiquarks; mesons containing only d, u and s quarks and antiquarks form the central hexagon; mesons containing a c quark or antiquark are shown to the right and left; mesons containing a b quark or antiquark are shown below and above; see what about the bottom row? below for more

what about the bottom row?

some mesons contain a quark and its own antiquark (e.g. the φ meson contains an s quark and an s antiquark), or a superposition of such states (e.g. the η meson is a combination of a u u, a d d and an s s); because all these mesons have a neutral flavour (as much s as s, etc.), they all belong at the centre of the central hexagon, but since there's no room for them all there, they are shown in a row at the bottom

what's missing?

mesons that contain top quarks are not shown, because these have such high mass that it is difficult to create them in particle accelerators

what's the significance of spin?

all mesons have integer spin (pseudoscalar mesons spin 0, vector mesons spin 1); in other words, all mesons are bosons, not subject to the exclusion principle, which means that there is no limit to the number of mesons you can squeeze into a small space; this is what allows the pion, Kaon and J/ψ to be involved in the strong nuclear force

Date

First published 31 March 2011

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