Perl, Martin L (1927– )

US physicist who was awarded the Nobel Prize for Physics in 1995 for the discovery of the tau particle, one of the elementary particles which make up all matter. He shared the award with Frederick Reines.

Perl and his colleagues discovered, through a series of experiments 1974–77, at the Stanford Linear Accelerator Center (SLAC), California, that the electron has a relative, some 3,500 times heavier, which is now called the tau. This was the first sign that a third ‘family’ of elementary particles existed. Without the existence of this third family, the standard model of elementary particles would be incomplete and unable to explain the properties of the elementary particles.

Perl was born in New York City in 1927 and educated in chemical engineering at the Polytechnic Institute of Brooklyn. His studies were interrupted by World War II; he received his bachelor's degree in 1948. From 1948 to 1950 he worked as a chemical engineer with the General Electric Company in Schenectady, New York. He entered his physics doctoral programme at Columbia University, New York, in 1950 and was awarded his doctorate in 1955. He moved to the University of Michigan in 1955 as an instructor, later becoming assistant professor and associate professor of physics. In 1963 he was appointed professor of physics and group leader of the High-Energy Physics Faculty, at the Stanford Linear Accelerator Center. In 1991 he became chairman of faculty.