Gluon (Gabi)

Information

The gluon was first discovered through experimental verification in 1979 at the PETRA Particle Accelerator in Hamburg, Germany.

The gluon solves the question: Why doesn't the nucleus blow apart due to the positively-charged protons repelling each other?

Quarks have type of charge called a color charge. The force between these color-charged particles is called the strong force. This force holds quarks together to form hadrons. The particles that carry this force are called gluons.

Quarks can have one of three color charges: red, green, or blue. Antiquarks can have one of three anticolor charges: antired, antigreen, or antiblue. The anticolors are the complementary colors to the regular colors.

Gluons carry both a color and an anticolor charge.

When quarks are confined into hadrons, the hadrons are color neutral. The quarks in a given hadron are constantly exchanging gluons. The color forcefield that links two quarks in a given hadron increases in energy as the quarks are pulled apart. At some point, the quarks snap into a new quark-antiquark pair (think of a rubber band being stretched to the point of snapping).

When quarks emit or absorb gluons, color charge must be conserved. If a red quark changes into a blue quark and emits a red/antiblue gluon, the net color would still be red because the blue color of the quark cancels with the antiblue of the gluon, leaving the remaining color red.

So, the strong force overcomes the repulsive electromagnetic force in the nucleus and is able to hold the nucleus of the atom together.

Current Experiments

It is hypothesized that at extremely high temperature and high density, a phase exists where (almost) free quarks and gluons are roaming about. This plasma is thought to be something akin to the state of the early universe. The QGP is being studied at Brookhaven National Laboratory's Relativistic Heavy Ion Collider in New York.

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