Perl , Martin Lewis
(1927–) American physicist
Born in New York, Perl first graduated in chemistry in 1948 at the Brooklyn Polytechnic Institute. After working in industry as a chemical engineer for General Electric, Perl became interested in nuclear physics. Consequently he returned to college and in 1955 he was awarded his PhD from Columbia, New York. He immediately moved to the University of Michigan, where he remained until he took up his present position of professor of physics at Stanford, California, in 1963.
In 1972 physicists were aware of four leptons: the electron, the muon, and their corresponding neutrinos. Further, leptons, unlike hadrons such as the proton, are genuinely pointlike elementary particles, which interact by the weak force. In 1972 Stanford opened its new accelerator, SPEAR (Stanford Positron–Electron Asymmetry Ring). While no new lepton had been found since the discovery of the muon in 1936, Perl decided to use the SPEAR facilities to see whether the lepton family could be extended.
Theoretical reasons led him to believe that any new lepton would have a charge of plus or minus 1, have a mass greater than a billion electronvolts (1 GeV), decay in less than a billionth of a second, and respond only to the weak and electromagnetic forces. Like any other particle, the new lepton would have to be identified by detecting its characteristic decay products. The particle had been named the ‘tau particle’ from the initial letter of the Greek word for third, ‘triton’. Perl argued that the tau would decay into either a muon or an electron, plus a neutrino and an antineutrino. In 1974 a sample of 10,000 events yielded twenty-four of the predicted kind. Despite some initial skepticism the existence of a heavy lepton with a mass greater than the proton was quickly confirmed.
Perl's discovery had an important theoretical implication. The four previously known leptons were linked with the four known quarks. The discovery of a new lepton, therefore, suggested the symmetry could only be maintained by the existence of a new quark. The prediction was confirmed in 1977 when Leon Lederman discovered the upsilon particle. For his discovery of the tau particle, Perl shared the 1995 Nobel Prize for physics with Frederick Reines.

Scientists. . 2011.

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  • PERL, MARTIN LEWIS — (1927– ), U.S. physicist and Nobel laureate. Perl was born in Brooklyn, New York City, and graduated early from Madison High School (1943), his education boosted by strong parental encouragement, prodigious reading and a great interest in working …   Encyclopedia of Judaism

  • Perl, Martin Lewis — ▪ American physicist born June 24, 1927, New York, N.Y., U.S.       American physicist who received the 1995 Nobel Prize for Physics for discovering a subatomic particle that he named the tau, a massive lepton with a negative charge. The tau,… …   Universalium

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  • Martin Lewis Perl — (24 juin 1927 à New York) est un physicien américain. Il est lauréat de la moitié du prix Nobel de physique de 1995 pour sa découverte du lepton tau[1] …   Wikipédia en Français

  • Physiknobelpreis 1995: Martin Lewis Perl — Frederick Reines —   Die Amerikaner wurden für »ihre experimentellen Pionierbeiträge auf dem Gebiet der Leptonphysik« ausgezeichnet.    Biografien   Martin Lewis Perl, * New York 24. 6. 1927; 1948 Abschluss des Chemiestudiums in New York, danach Physikstudium und… …   Universal-Lexikon

  • Martin L. Perl — Martin Lewis Perl Martin Lewis Perl Martin Lewis Perl, né le 24 juin 1927 à New York, est un physicien américain, qui a obtenu le prix Nobel de physique en 1995 pour sa découverte du lepton tau. Ses parents étaient des immigrants venant de la… …   Wikipédia en Français

  • Martin Perl — Martin Lewis Perl Martin Lewis Perl Martin Lewis Perl, né le 24 juin 1927 à New York, est un physicien américain, qui a obtenu le prix Nobel de physique en 1995 pour sa découverte du lepton tau. Ses parents étaient des immigrants venant de la… …   Wikipédia en Français

  • Martin L. Perl — Martin Lewis Perl (* 24. Juni 1927 in New York) ist ein US amerikanischer Physiker. Für seine Entdeckung des Tauons erhielt er zusammen mit Frederick Reines 1995 den Nobelpreis für Physik. Perl ist der Sohn jüdischer Einwanderer aus dem damals zu …   Deutsch Wikipedia

  • Perl — (izg. pȇrl), Martin Lewis (1927) DEFINICIJA američki kemičar i fizičar; Nobelova nagrada za fiziku 1995. (s F. Reinesom) …   Hrvatski jezični portal

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