Jerome Isaac Friedman
active c. 1930, Chicago, Illinois, USA
American physicist who shared the 1990 Nobel Prize in Physics for deep inelastic electron–proton scattering experiments that revealed quarks inside the proton.
Born in Chicago, Friedman initially studied art before turning to physics at the University of Chicago, where he earned his PhD in 1956 working under Enrico Fermi and later Valentine Telegdi. He joined MIT in 1960 and, with Henry Kendall and Richard Taylor, led the MIT–SLAC collaboration that from 1967 scattered high-energy electrons off protons at Stanford's linear accelerator. The unexpectedly strong scattering at large momentum transfer showed the proton contains point-like constituents — the first direct evidence for quarks. He directed MIT's nuclear science laboratory (1983–1988).
Nobel-winning work
Between 1967 and 1973 Friedman, Kendall and Taylor ran the SLAC–MIT deep inelastic scattering program: 20 GeV electrons struck hydrogen and deuterium targets, and the recoiling electrons were analyzed with large spectrometers. The measured structure functions showed 'scaling' — they depended on a single dimensionless variable x — exactly as Bjorken predicted for scattering off point-like, nearly free partons inside the proton.
Feynman's parton interpretation identified those partons with the quarks of Gell-Mann and Zweig. The experiments also found roughly half the proton's momentum carried by neutral constituents — later identified as gluons — founding modern QCD phenomenology.
Workplaces: Massachusetts Institute of Technology
United States