(1922–    ), American physicist and Nobel laureate who made significant contributions to the field of particle physics (see Elementary Particles; Physics).

Born on July 15, 1922, in New York, N.Y., he was educated at City College (now part of the City University of New York) before pursuing his graduate studies at Columbia University, where he earned a Ph.D. in 1951. That same year he joined Columbia’s NEVIS Laboratory, located in Irvington-on-the-Hudson, N.Y., where he had been working since 1948 on the cyclotron project. He also taught at Columbia, becoming a professor there in 1958. From 1961 to 1978 he was director at NEVIS, where most of his researh was done; he also did research at the European Organization for Nuclear Research, known as CERN, in Geneva, Switzerland; at the Brookhaven National Laboratory, in Upton, Long Island, N.Y.; and at the Fermi National Accelerator Laboratory (Fermilab), in Batavia, Ill., which he headed from 1979 to 1989. He taught at the University of Chicago (1989–92) and then at the Illinois Institute of Technology.

In the 1960s, Lederman, together with two colleagues at Columbia—Melvin Schwartz and Jack Steinberger—worked for eight months at Brookhaven National Laboratory to isolate and study neutrinos. At that time only one type of neutrino was detected—the electron type. In their experiment, which led to the discovery of the muon type of neutrino in 1962, they used a beam of neutrinos they produced in a particle accelerator in the decay (disintegration) of charged pi-meson. The mesons decay into a muon and a neutrino each and also into other particles. To eliminate all but the neutrino particles they used a thick steel wall. The detector, a 10-ton spark chamber for measuring the particles, was built behind the wall. The results showed that only one type of neutrino was produced in the beam. This new type paired with the muon (like electrons, muons are subatomic particles that are classified as leptons) and was, accordingly, called the muon neutrino. (The electron and the muon types of neutrinos are electrically negative but different in mass; the mass of the muon is 200 times that of the electron.) Their work led scientists to the discovery that there is a family structure to subatomic particles. A third type, the tau neutrino, was discovered by other scientists in the 1970s.

Lederman, Schwartz, and Steinberger were awarded the 1988 Nobel Prize in physics “for the neutrino beam method and the demonstration of the doublet structure of the leptons through the discovery of the muon neutrino.”

See also Atom and Atomic Theory; Particle Accelerators; Particle Detectors.