Murray Gell-Mann is an American physicist who received the 1969 Nobel Prize in physics for his work on the theory of elementary particles. He is the Robert Andrews Millikan Professor of Theoretical Physics Emeritus at the California Institute of Technology, a Distinguished Fellow and co-founder of the Santa Fe Institute, Professor in the Physics and Astronomy Department of the University of New Mexico, and the Presidential Professor of Physics and Medicine at the University of Southern California.
He introduced the quark constituents of all hadrons, having first identified the SU flavor symmetry of hadrons, now understood to underlie the light quarks, extending isospin to include strangeness, a quantum number which he also discovered.
He developed the Vâˆ’A theory of the weak interaction in collaboration with Richard Feynman. In the 1960s, he introduced current algebra as a method of systematically exploiting symmetries to extract predictions from quark models, in the absence of reliable dynamical theory. This method led to model-independent sum rules confirmed by experiment and provided starting points underpinning the development of the standard theory of elementary particles.