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Isotopic spin


Dick Dalitz; tau decay
Murray Gell-Mann Scientist
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Dick Dalitz did some beautiful work on the spectrum of the three pions in the so-called tau decay–what is now called a charged K particle–decayed into three charged pions. And that mode of decay was originally thought to be a special particle and was called tau. And what Dick did was to study the spectrum of tau decay; what it indicated about the symmetry of the wave function of the three pions, and therefore about the isotopic spin of the three pions. And he showed that the three pions were in an isotopic spin 1 state. Well that paper should have been received with great enthusiasm by the theoretical physics community, but instead some people told Dalitz that he should probably not work on this kind of thing; that for a young theorist to study this kind of problem was unwise because he would get the reputation of being the sort of theorist who studied these weird things. Now what was so weird about studying the spectrum of a decay that had been observed in the laboratory I don't know, but it was somehow not respectable.

New York-born physicist Murray Gell-Mann (1929-2019) was known for his creation of the eightfold way, an ordering system for subatomic particles, comparable to the periodic table. His discovery of the omega-minus particle filled a gap in the system, brought the theory wide acceptance and led to Gell-Mann's winning the Nobel Prize in Physics in 1969.

Listeners: Geoffrey West

Geoffrey West is a Staff Member, Fellow, and Program Manager for High Energy Physics at Los Alamos National Laboratory. He is also a member of The Santa Fe Institute. He is a native of England and was educated at Cambridge University (B.A. 1961). He received his Ph.D. from Stanford University in 1966 followed by post-doctoral appointments at Cornell and Harvard Universities. He returned to Stanford as a faculty member in 1970. He left to build and lead the Theoretical High Energy Physics Group at Los Alamos. He has numerous scientific publications including the editing of three books. His primary interest has been in fundamental questions in Physics, especially those concerning the elementary particles and their interactions. His long-term fascination in general scaling phenomena grew out of his work on scaling in quantum chromodynamics and the unification of all forces of nature. In 1996 this evolved into the highly productive collaboration with James Brown and Brian Enquist on the origin of allometric scaling laws in biology and the development of realistic quantitative models that analyse the influence of size on the structural and functional design of organisms.

Tags: Dick Dalitz

Duration: 1 minute, 14 seconds

Date story recorded: October 1997

Date story went live: 24 January 2008