Martin Perl Wins Nobel Prize in Physics

Stanford Linear Accelerator Center - Martin Perl, a professor at the Stanford Linear Accelerator Center (SLAC), has been awarded the 1995 Nobel Prize in Physics. He will be presented the award in Stockholm, Sweden this December for his 1975 discovery of a new elementary particle known as the tau lepton.

Perl, 68, received the news of his selection at home in San Francisco when he received a call from the Associated Press.

"I still can't believe it," said Perl. "At first I thought that someone had made a mistake."

"All of us at Stanford are elated at the news, said Burton Richter, recipient of the 1976 Nobel Prize for physics and director of SLAC. "Perl's discovery came as a complete surprise to the physics world. This is a well-deserved award."

The tau lepton is a superheavy cousin of the electron -- the carrier of electrical current in household appliances. The two particles are identical in all respects except that the tau is more than 3,500 times heavier than the electron and survives less than a trillionth of a second, whereas the electron is stable.

In the mid-1970s, working on the Stanford Positron-Electron Asymmetric Ring (SPEAR) with a collaboration of 30 other physicsts from SLAC and Lawrence Berkeley National Laboratory, Perl began to find event records by their detector that could not be explained by any of the known subatomic particles. After more than a year of analysis, Perl was able to convince the rest of his team that they were in fact observing a new and different type of elementary particle, which he named the tau.

In the Standard Model of particle physics, the elementary building blocks of matter appear in families, with two leptons and two quarks in each. Until Perl's discovery there were only two such families known to exist.

Dr. Perl discovered the first member of a third quark-lepton family. In 1976, the bottom quark was discovered by Fermi National Accelerator Laboratory, followed in 1995 by the discovery of the third member: the top quark.

Perl was awarded the Wolf Prize for his discovery of the tau in 1982.

Dr. Perl received his Ph.D. in 1955 from Columbia University, where he studied under Professor I. I. Rabi, winner of the 1944 Nobel Prize in physics. He is a member of the National Academy of Sciences and a Fellow of the American Physical Society (APS).

Dr. Perl has been on the faculty at SLAC since 1963.

The mission of the Stanford Linear Accelerator Center is to design, construct, and operate highly advanced electronic accelerators and experimental facilities for high-energy physics and synchrotron radiation research and to engage in fundamental science. SLAC is a national user facility managed for the Department of Energy by Stanford University.


Last modified October 18, 1995