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. 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, 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.
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).