Messenger particle

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Messenger particles are sub-atomic particles that are exchanged between matter and are responsible for force, (i.e., electromagnetic). An example of a messenger particle is a photon, which is responsible for the electromagnetic force.

1 Types
2 Overview
3 History
4 See also
5 External links

[edit] Types

There are four in total, each corresponding to one of the four fundamental forces of nature:

Gluon - carries the strong nuclear force.
Photon - carries the electromagnetic force.
W and Z bosons - carry the weak nuclear force
Graviton - hypothetical particle which is postulated to carry either the gravitational force or (in the case of general relativity) information on changes in the gravitational field.

[edit] Overview

All elementary particles are either bosons or fermions (depending on their spin). The spin-statistics theorem identifies the resulting quantum statistics that differentiate fermions and bosons.

Interaction of virtual bosons with real fermions are called fundamental interactions. Momentum conservation in these interactions mathematically results in all forces we know. The bosons involved in these interactions are called gauge bosons - such as the W vector bosons of the weak force, the gluons of the strong force, the photons of the electromagnetic force, and (in theory) the graviton of the gravitational force. A graviton is the theoretical messenger particle believed to be responsible for the gravitational force, however its existence has yet to be experimentally confirmed

[edit] History

The concept of messenger particles dates back to the 18th century when French Physicist Charles Coulomb showed that the electrostatic force between electrically charged objects follows a law similar to Newton's law of gravitation. In time, this relation became known as Coulomb's law. By 1862, Hermann von Helmholtz had described a ray of light as the “quickest of all the messengers”. In 1905, Albert Einstein proposed the existence of a light-particle in answer to the question: “what are light quanta?” In 1923, through the work of Arthur Compton at Washington University in St. Louis, Einstein’s light-particle idea was made undeniably plain to physicists. Lastly, in 1926, one year before the theory of quantum mechanics was completed, Gilbert N. Lewis introduced the term “photon”, which subsequently became the name for Einstein’s light particle. From here the concept of messenger particles developed further.