In physics, the electroweak theory presents a unified description of two of the four fundamental forces of nature: electromagnetism and the weak nuclear force. Although these two forces appear very different at everyday low energies, the theory models them as two different aspects of the same force. Above the unification energy, on the order of 10^{2}GeV, they would merge into a single electroweak force.

Mathematically, the unification is accomplished under an SU(2) × U(1) gauge group. The corresponding gauge bosons are the photon of electromagnetism and the W and Z bosons of the weak force. In the Standard Model, the weak gauge bosons get their mass from the spontaneous symmetry breaking of the electroweak symmetry from SU(2) × U(1)_{Y} to U(1)_{em}, caused by the Higgs mechanism. The subscripts are used to indicate that these are different copies of U(1); the generator of U(1)_{em} is given by Q = Y/2 + I_{3}, where Y is the generator of U(1)_{Y} (called the hypercharge), and I_{3} is one of the SU(2) generators (a component of isospin). The distinction between electromagnetism and the weak force arises because there is a (nontrivial) linear combination of Y and I_{3} that vanishes for the Higgs boson (it is an eigenstate of both Y and I_{3}, so the coefficients may be taken as −I_{3} and Y): U(1)_{em} is defined to be the group generated by this linear combination, and is unbroken because it doesn't interact with the Higgs.

The term "electroweak interaction" describes the modern theory of two interactions: electromagnetic and weak.

Nearly 100 years later, the developers of electroweak theory made another giant conceptual leap, unifying Maxwell's electromagnetism (or rather its quantum field theory descendant, quantum electrodynamics or QED) with the theory of the weak interactions.

The electroweak theory was developed in the period from 1961-1967, primarily by the work of Sheldon Glashow, Steven Weinberg, and Abdus Salam, who were awarded the Nobel Prize in 1979 for this work.

ELECTROWEAK THEORY [electroweak theory] a unified field theory that describes two of the fundamental forces in nature, electromagnetism (see electromagnetic radiation) and the weak interaction.

The electroweak theory derived from efforts to produce a theory for the weak force analogous to quantum electrodynamics (QED), the quantum theory of the electromagnetic force.

The electroweak theory, for which Sheldon Glashow, Abdus Salam, and Steven Weinberg shared the 1979 Nobel Prize in Physics, was confirmed in 1983 by the discovery of the W and Z particles, two of a number of elementary particles it predicted.

Share your thoughts, questions and commentary here

Want to know more? Search encyclopedia, statistics and forums:

Press Releases |
Feeds |
Contact
The Wikipedia article included on this page is licensed under the
GFDL.
Images may be subject to relevant owners' copyright.
All other elements are (c) copyright NationMaster.com 2003-5. All Rights Reserved.
Usage implies agreement with terms, 1022, m