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Wigner, Eugene Paul

nuclear physics reaction theory

[ wig ner] (1902–95) Hungarian–US physicist: applied group theory to quantum mechanics and discovered parity conservation in nuclear reactions.

Wigner was the son of a businessman and took his doctorate in engineering at the Berlin Institute of Technology in 1925. He moved to Princeton in 1930, became professor of theoretical physics there in 1938 and held this post until his retirement in 1971. He was a brother-in-law of .

He made major contributions in quantum theory and nuclear physics, in particular by showing the value of symmetry concepts and the methods of group theory applied to physics. In 1927 he concluded that parity is conserved in a nuclear reaction: the laws of physics should not distinguish between right and left; or between positive and negative time. As a consequence a nuclear reaction between particles and the mirror image of those particles will be identical, and this was accepted to apply to all types of reaction. However, very surprisingly, identified a class of exceptions to this law of parity conservation in 1958. Reactions involving the weak nuclear force, such as beta decay when an electron is emitted from a nucleus, do not conserve parity.

Wigner’s research during the 1930s mainly concerned neutrons and he investigated the strong nuclear interaction which binds neutrons and protons in the nucleus. He showed that the force has a very short range and does not involve electrical charge. The formula describing how moving neutrons interact with a stationary nucleus was given by and Wigner in 1936. Using this and other discoveries, Wigner assisted in constructing the first nuclear reactor to produce a sustained nuclear chain reaction in Chicago in 1942. For his contributions to quantum theory and applying it to nuclear physics Wigner shared the 1963 Nobel Prize for physics.

Wilcots, Joseph M. (1939–) [next] [back] Wiener, Norbert

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