Sheldon Lee Glashow
active c. 1932, New York City, USA
American theoretical physicist who formulated the SU(2)×U(1) electroweak gauge structure and predicted the charm quark.
A Bronx Science classmate of Weinberg, Glashow took his doctorate under Schwinger at Harvard. In 1961 he proposed unifying weak and electromagnetic forces in an SU(2)×U(1) gauge theory — the correct symmetry group, though masses still had to be inserted by hand. With Iliopoulos and Maiani he later showed that a fourth 'charm' quark would suppress unwanted strangeness-changing neutral currents, a prediction spectacularly confirmed by the J/ψ in 1974.
Nobel-winning work
Glashow's share of the 1979 Nobel Prize rested on his 1961 paper 'Partial Symmetries of Weak Interactions', which first embedded the weak force in the SU(2)×U(1) gauge structure — the correct group of the electroweak theory, complete with a neutral gauge boson mixing the photon and Z.
His 1970 GIM mechanism, requiring a fourth quark, explained the absence of flavor-changing neutral currents and led directly to the prediction of charm — vindicated by the November 1974 discovery of the J/ψ. Together these works supplied the symmetry skeleton and the quark content of the modern electroweak theory.
Workplaces: Harvard University
United States