Gluon
A gluon (/ˈɡluːɒn/ GLOO-on) is a type of elementary particle that mediates the strong interaction between quarks, acting as the exchange particle for the interaction. Gluons are massless vector bosons, thereby having a spin of 1. Through the strong interaction, gluons bind quarks into groups according to quantum chromodynamics (QCD), forming hadrons such as protons and neutrons.
Diagram 1: In Feynman diagrams, emitted gluons are represented as helices. This diagram depicts the annihilation of an electron and positron. | |
| Composition | Elementary particle |
|---|---|
| Statistics | Bosonic |
| Family | Gauge boson |
| Interactions | Strong interaction |
| Symbol | g |
| Theorized | Murray Gell-Mann (1962) |
| Discovered | e+e− → Υ(9.46) → 3g: 1978 at DORIS (DESY) by PLUTO experiments (see diagram 2 and recollection) and |
| Types | 8 |
| Mass | 0 (theoretical value) < 1.3 MeV/ (experimental limit) |
| Electric charge | 0 e |
| Color charge | octet (8 linearly independent types) |
| Spin | 1 ħ |
| Parity | -1 |
| Standard Model of particle physics |
|---|
Gluons carry the color charge of the strong interaction, thereby participating in the strong interaction as well as mediating it. Because gluons carry the color charge, QCD is more difficult to analyze compared to quantum electrodynamics (QED) where the photon carries no electric charge.
The term was coined by Murray Gell-Mann in 1962 for being similar to an adhesive or glue that keeps the nucleus together. Together with the quarks, these particles were referred together as partons by Richard Feynman.