Murray Gell-Mann. Portrait of Murray Gell-Mann (born 1929), American theoretical physicist. Ent- ering University aged 15, Gell-Mann had a doctor- ate by the age of 22. Two years later he intro- duced the concept of strangeness to explain the properties of some newly-discovered subatomic particles. Gell-Mann and Ne'eman used this to put particles into groupings. In 1962 this allowed them to predict the existence of the hyperon or omega minus particle (observed 1964). In 1964 Gell-Mann and Zweig postulated that the particles that made up atomic nuclei were themselves com- prised of smaller particles (quarks). He won the 1969 Nobel Physics Prize. Photographed in 1995.