Physicist Martin L. Perl, who won the 1995 Nobel Prize for the discovery of a fundamental particle of nature, the tau lepton, has died at age 87.
A professor emeritus of physics at Stanford University and the SLAC National Accelerator Laboratory, Perl died Sept. 30 at Stanford Hospital in Palo Alto, Calif., the university reported.
Perl was awarded the Novel Prize for work he began at the Stanford Linear Accelerator Center in the 1970s.
When he began the work, the Standard Model of physics describing fundamental particles and forces of nature was considered to be complete, with all likely subatomic particles, including quarks and leptons, thought to have been identified.
Two classes of leptons had been discovered; Perl maintained there should be more, and he set out to find them between 1974 and 1977 using a new kind of particle accelerator at SLAC to smash electrons and positrons together.
"People wanted me to be cautious," Perl said in a 2013 interview at Stanford. "We kept taking data, and the evidence kept coming in. Every month or so we would get another handful -- 10 to 20 -- of these funny [collision] events. I gave a lot of talks. There would be all sorts of objections... We eventually eliminated every other explanation."
His discovery, the tau lepton, turned out to have 3,5000 times the mass of its cousin, the electron.
After Perl and his research team published their findings, confirmation of the tau lepton's existence began to come from other research institutions.
"Eventually other people began to find them, too," Perl said.
Perl was born in New York City in 1927, the son of immigrants who fled poverty and anti-Semitism in the Polish area of Russia.
He graduated from high school at age 16 and started college, which was interrupted by military service in World War II.
He resumed his studies after the war and received a degree in chemical engineering, in 1948.
After working for General Electric, he returned to school and earned a doctorate in physics at Columbia University.
After a teaching stint at the University of Michigan, he joined the staff at the Stanford Linear Accelerator Center as it was being constructed in 1963.
Long after formal retirement, he continued to contribute at SLAC, recently taking part in a NASA-funded investigation of dark energy.
"He was so excited to come to the lab," said his son Joseph Perl, who is also a researcher at the Stanford facility. "It was the one place in the whole world to be, to do what he wanted to do. One of the topics that interested him was creativity in science; he always advocated that you should look at what the crowd is doing and go in a different direction."
