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). 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 meson to , 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". 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, 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, but the nomination failed. Zweig later turned to research on hearing and neurobiology, and studied the
transduction of
sound into
nerve impulses in the
cochlea of the
human ear, and how the brain maps sound onto the spatial dimensions of the cerebral cortex. In 1975, while studying the ear, 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. ==Awards and honors==