Martin Lewis Perl led the team that definitively detected the tau particle between 1974 and 1977. His group worked at the Stanford Linear Accelerator Center alongside colleagues from Lawrence Berkeley National Laboratory.
A tau particle carries a negative electric charge and spins like other elementary particles. Its mass is significantly larger than that of muons or electrons.
In 1960, a team at CERN began looking for something new with Antonino Zichichi leading the Bologna, CERN, Frascati group in this early search. They hoped to find a heavy lepton that had not yet been seen.
The tau stands alone among leptons because it has enough mass to decay into hadrons. Hadronic decay occurs through the weak interaction just like purely leptonic modes.
Martin Lewis Perl shared the 1995 Nobel Prize in Physics with Frederick Reines. The detection occurred between 1974 and 1977 while the prize was awarded in 1995.