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electroweak theory

(Encyclopedia)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 der...

weak interactions

(Encyclopedia)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 interaction...

Friedman, Jerome Isaac

(Encyclopedia)Friedman, Jerome Isaac frēdˈmən [key], 1930–, American physicist, b. Chicago, Ph.D. Univ. of Chicago, 1956. A professor at the Massachusetts Institute of Technology, Friedman won the 1990 Nobel P...

hyperon

(Encyclopedia)hyperon hīˈpərŏnˌ [key], class of elementary particles heavier than nucleons (proton and neutron). The nucleons and the hyperons together make up the baryon family of particles. ...

quark

(Encyclopedia)quark kwôrk [key]: see elementary particles. ...

van der Waals forces

(Encyclopedia)van der Waals forces: see intermolecular forces. ...

boson

(Encyclopedia)boson: see elementary particles; Bose-Einstein statistics. ...

Taylor, Richard Edward

(Encyclopedia)Taylor, Richard Edward, 1930–2018, Canadian experimental physicist. He was associated primarily with Stanford, where he received his doctorate (1962) and helped build and then worked—first (1962) ...

tachyon

(Encyclopedia)tachyon tăkˈēŏnˌ [key], hypothetical elementary particle that travels only at speeds exceeding that of light. According to the theory of relativity, the speed of light is the limiting velocity fo...

exclusion principle

(Encyclopedia)exclusion principle, physical principle enunciated by Wolfgang Pauli in 1925 stating that no two electrons in an atom can occupy the same energy state simultaneously. The energy states, or levels, in ...