Zweig proposed the existence of quarks at CERN, independently of Murray Gell-Mann, shortly after defending his PhD dissertation. Zweig dubbed them "aces", after the four playing cards, because he speculated there were four of them (on the basis of the four extant leptons known at the time).[3][4] The introduction of the concept of quarks provided a cornerstone for particle physics.
Like Gell-Mann, he realized that several important properties of particles such as baryons (e.g., protons and neutrons) could be explained by treating them as triplets of other constituent particles, with fractional baryon number and electric charge. Unlike Gell-Mann, Zweig was partly led to his picture of the quark model by the peculiarly attenuated decays of the φ meson to ρ π,[5][6] a feature codified by what is now known as the OZI Rule, the "Z" in which stands for "Zweig". In subsequent technical terminology, ultimately Gell-Mann's quarks were closer to "current quarks", while Zweig's to "constituent quarks".[7]
Gell-Mann received the Nobel Prize for physics in 1969, for his overall contributions and discoveries concerning the classification of elementary particles and their interactions; at that time, quark theory had not become fully accepted,[8] and was not specifically mentioned in the official citation of the prize. In 1977 Richard Feynman nominated both Zweig, and Gell-Mann again, for the Nobel prize,[9] but the nomination failed.[10]
Zweig later turned to research on hearing and neurobiology, and studied the transduction of sound into nerve impulses in the cochlea of the humanear,[11] and how the brain maps sound onto the spatial dimensions of the cerebral cortex. In 1975, while studying the ear,[12] he introduced a version of the continuous wavelet transform, the cochlear transform.
In 2003, Zweig joined the quantitative hedge fund Renaissance Technologies, founded by the former Cold War code breaker James Simons. He left the firm in 2010. Once his four-year confidentiality agreement with Renaissance Technologies expired, the 78-year-old Zweig returned to Wall Street and co-founded a quantitative hedge fund, called Signition, with two younger partners. They began trading in 2015.[13]
^G. Zweig (1964), "An SU(3) model for strong interaction symmetry and its breaking II", Published in 'Developments in the Quark Theory of Hadrons'. Volume 1. Edited by D. Lichtenberg and S. Rosen. Nonantum, Mass., Hadronic Press, 1980. pp. 22-101 and CERN Geneva - TH. 412 (21 Feb. 1964) 76p.
^Missing hadronic resonance states predicted by the quark model were only established in the early 1970s. Appreciation that flavor SU(3) reflects nothing beyond the symmetries of the three lightest quarks had to wait until the late 1970s. Understanding of the reason free quark searches were turning up negative was lacking until 1974.
