Jack Steinberger
1921–2020, Bad Kissingen, Germany, Geneva, Switzerland
German-born American physicist who shared the 1988 Nobel Prize in Physics for the two-neutrino experiment, and who later measured CP violation and led the ALEPH experiment at CERN.
Born Hans Steinberger in Bad Kissingen, Germany, he fled Nazi persecution in 1934 thanks to American Jewish charities, settling in Chicago. He studied under Enrico Fermi at the University of Chicago, earning his PhD in 1948 with measurements of the muon decay spectrum that showed the decay emits three bodies. At Columbia (1950–1971) he co-led the two-neutrino experiment, then moved to CERN where he helped discover CP-violating decays of neutral kaons and later served as spokesman of the ALEPH experiment at LEP.
Nobel-winning work
In 1962 Steinberger shared the leadership of the Brookhaven two-neutrino experiment: a neutrino beam from pion decay traversed ~13.5 m of shielding steel and interacted in a 10-ton spark chamber, yielding muons but no electrons. The team concluded that nature possesses two distinct neutrino species, ν_e and ν_μ.
The discovery — published in Physical Review Letters in 1962 with less than 60 observed events — founded high-energy neutrino physics and anticipated the generational structure of leptons and quarks in the Standard Model.
Workplaces: Columbia University, CERN
United States, Germany