Knowra November Revolution November Revolution The November Revolution was the 1974 transformation of particle physics after the simultaneous discovery of the J/ψ particle by teams at Brookhaven and SLAC. It established compelling evidence for charm quarks and reshaped the developing Standard Model.
J/ψ particle : A narrow charmonium meson composed of a charm quark and its antiquark, discovered in 1974. Its unexpectedly sharp resonance was the discovery that triggered the revolution.
Charm quark : A second-generation quark with electric charge +2/3 and a mass far greater than the up quark’s. The J/ψ is a bound state of charm and anticharm, giving direct evidence for charm.
November Revolution in particle physics : A broader historical label for the upheaval in particle physics associated with the 1974 J/ψ discovery. This label distinguishes the scientific transformation from other events called the November Revolution.
Three-quark model : The early quark scheme containing up, down, and strange quarks. The J/ψ could not fit naturally into the established three-flavor particle scheme.
Brookhaven National Laboratory : A United States research laboratory where Samuel Ting’s team discovered the J particle in 1974. Ting’s group found the resonance in proton–beryllium collisions, independently of SLAC.
Quark model : A framework that classifies hadrons as bound states of quarks. The charm interpretation extended this framework beyond its three established quark flavors.
Charmonium spectroscopy : The study of charmonium energy levels, transitions, and decay properties. The new bound states offered a rich, measurable spectrum for testing quantum chromodynamics.
GIM mechanism : A mechanism proposed by Sheldon Glashow, John Iliopoulos, and Luciano Maiani to suppress flavor-changing neutral currents using charm. Charm had been proposed theoretically before the J/ψ made its existence compelling experimentally.
SLAC National Accelerator Laboratory : A Stanford research laboratory where Burton Richter’s team discovered the ψ particle in 1974. Richter’s group observed the same resonance in electron–positron collisions.
Quarkonium : A meson made from a heavy quark and its own antiquark. The J/ψ’s unusually narrow resonance identified it as a heavy quark–antiquark bound state.
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