Lederman, Leon Max

▪ American physicist

born July 15, 1922, New York, N.Y., U.S.

      American physicist who, along with Melvin Schwartz (Schwartz, Melvin) and Jack Steinberger (Steinberger, Jack), received the Nobel Prize for Physics in 1988 for their joint research on neutrinos.

      Lederman was educated at the City College of New York (B.S., 1943) and received his Ph.D. in physics from Columbia University, New York City, in 1951. He joined the faculty at Columbia that same year and became a full professor there in 1958. He was director of the Fermi National Accelerator Laboratory in Batavia, Ill., from 1979 to 1989.

      From 1960 to 1962, Lederman, together with his fellow Columbia University researchers Schwartz and Steinberger, collaborated in an important experiment at the Brookhaven National Laboratory on Long Island, N.Y. There they used a particle accelerator to produce the first laboratory-made beam of neutrinos (neutrino)—elusive subatomic particles that have no detectable mass and no electric charge and that travel at the speed of light. It was already known that when neutrinos interact with matter, either electrons or electron-like particles known as muons (mu mesons) are created. It was not known, however, whether this indicated the existence of two distinct types of neutrinos. The three scientists' work at Brookhaven established that the neutrinos that produced muons were indeed a distinct (and previously unknown) type of neutrino, one which the scientists named muon neutrinos. The discovery of muon neutrinos subsequently led to the recognition of a number of different “families” of subatomic particles, and this eventually resulted in the standard model, a scheme that has been used to classify all known elementary particles.

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