# electroweak theory

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## electroweak theory,

a unified field theory that describes two of the fundamental forces in nature, electromagnetism (see electromagnetic radiation**electromagnetic radiation,**

energy radiated in the form of a wave as a result of the motion of electric charges. A moving charge gives rise to a magnetic field, and if the motion is changing (accelerated), then the magnetic field varies and in turn produces an electric field.

**.....**Click the link for more information. ) and the weak interaction

**weak interactions,**

actions between elementary particles mediated, or carried, by W and Z particles and that are responsible for nuclear decay. Weak interactions are one of four fundamental interactions in nature, the others being gravitation, electromagnetism, and the strong interactions.

**.....**Click the link for more information. . The electroweak theory derived from efforts to produce a theory for the weak force analogous to quantum electrodynamics

**quantum electrodynamics**

(QED), quantum field theory that describes the properties of electromagnetic radiation and its interaction with electrically charged matter in the framework of quantum theory.

**.....**Click the link for more information. (QED), the quantum theory of the electromagnetic force. Although the weak force fails to meet a requirement for that theory—that it behave the same way at different points in space and time—because it acts only across distances smaller than an atomic nucleus, it was shown that the electromagnetic force, which can extend across interstellar distances, and the weak force are but different manifestations of a more fundamental force, the electroweak force. This made it possible to formulate a unified model that predicted the existence of mediating, or messenger, particles. The electroweak theory, for which Sheldon Glashow

**Glashow, Sheldon Lee**

, 1932–, American physicist, b. New York City, Ph.D. Harvard, 1959. He became a professor at the Univ. of California at Berkeley in 1961 before moving to Harvard in 1967.

**.....**Click the link for more information. , Abdus Salam

**Salam, Abdus,**

1926–96, Pakistani physicist. After attending Government College at Lahore, he received a Ph.D. from Cambridge (1952). He taught in Lahore for three years before returning to England, first teaching mathematics at Cambridge (1954–57), then moving to

**.....**Click the link for more information. , and Steven Weinberg

**Weinberg, Steven,**

1933–, American nuclear physicist, b. New York City, Ph.D. Princeton, 1957. Since 1982 he has been a professor at the Univ. of Texas at Austin, having previously been on the faculties of Columbia, the Univ.

**.....**Click the link for more information. shared the 1979 Nobel Prize in Physics, was confirmed in 1983 by the discovery of the W and Z particles

**W and Z particles,**

elementary particles that mediate, or carry, the fundamental force associated with weak interactions. The discovery of the

*W*and

*Z*particles at CERN near Geneva, Switzerland, in the early 1980s was an important confirmation of electroweak theory,

**.....**Click the link for more information. , two of a number of elementary particles

**elementary particles,**

the most basic physical constituents of the universe.

**Basic Constituents of Matter**

Molecules are built up from the atom, which is the basic unit of any chemical element. The atom in turn is made from the proton, neutron, and electron.

**.....**Click the link for more information. it predicted.

### Bibliography

See P. Renton, *Electroweak Interactions* (1990); J. Horejsi, *Introduction to Electroweak Unification* (1994); A. Salam, *Selected Papers of Abdus Salam* (1994); J. D. Walecka, *Theoretical Nuclear and Subnuclear Physics* (1995).