| Composition | 
 
 K− : s u  | 
|---|---|
| Statistics | Bosonic | 
| Interactions | Strong, weak, electromagnetic, gravitational | 
| Symbol | 
 K+ , K0 , K−  | 
| Discovered | 1947 | 
| Types | 4 | 
| Mass | 
 K± : 493.667±0.013 MeV/c2 K0 : 497.648±0.022 MeV/c2  | 
| Electric charge | 
 K± : ±1 e K0 : 0 e  | 
| Spin | 0 | 
| Strangeness | 1 | 
K+
: 
u
s
K0
: 
d
s
 / 
s
d
In particle physics, a kaon /ˈkeɪ.ɒn/, also called a K meson and denoted 
K
, is any of a group of four mesons distinguished by a quantum number called strangeness. In the quark model they are understood to be bound states of a strange quark (or antiquark) and an up or down antiquark (or quark).