Benjamin W. Lee, head of the theoretical physics department at the Fermi
National Accelerator Laboratory and professor of physics at the University
of Chicago, was tragically killed in an automobile accident near Kewanee,
Illinois on 16 June. He was travelling to the summer meeting of the
Fermilab Program Advisory Committee in Aspen, Colorado. The other
members of his family who were accompanying him were not seriously
injured. Lee was widely regarded as one of the world's leading physicists
working on the theory of elementary particles.
Born in Seoul, Korea in 1935, Lee came to the United States as a student,
receiving his BS degree from Miami University of Ohio in 1956. His
graduate work was at the University of Pittsburgh, where he received the
MS degree in 1958, and at the University of Pennsylvania, where he worked
under the direction of Abraham Klein, receiving the PhD degree in 1960. He
became a naturalized US citizen in 1968. After several years at
Pennsylvania and at the Institute for Advanced Study in Princeton, N.J.;
in 1966 Lee accepted a professorship at the Institute for Theoretical
Physics at the State University of New York, Stony Brook, which is
directed by C. N. Yang. He served there until his move to Fermilab in
Lee had one of the broadest ranges of interests and research of any
physicist of his generation, but he returned again and again to the study
of symmetry principles and the weak interactions. He was one of the first
of the physicists working on SU(6) and related symmetries in the
mid-1960s to propose that these symmetries would find their natural
expression through the algebra of currents. He then played a leading
role in the development and applications of current algebra and
phenomenological Lagrangians, culminating in the publication in 1972 of
his monograph on Chiral Dynamics. Lee turned in the early 1970s to the
fundamental problem of the renormalization of theories with
symmetry, such as the σ model, and developed ideas and techniques that
were to serve him well in his later work on gauge theories.
Lee's involvement with gauge theories dated back to 1964. He was concerned
about the fact that superconductors appear to provide a counterexample
to the general theorem, which requires that spontaneous symmetry breaking
is always accompanied with massless spin-zero bosons. With Klein, he
wrote an article suggesting that the same might occur in relativistic
theories. It was soon realized that this is indeed the case, provided the
broken symmetry is a gauge symmetry, as it is in a superconductor.
Lee continued to work on the quantization of spontaneously broken gauge
theories. In 1971, after it had been shown by functional methods that
these theories are renormalizable, Lee developed a proof
of this result (for Abelian gauge theories) by operator methods. For
theorists who were unfamiliar with the functional formalism, it was Lee's proof
that really settIed the matter. In the following year, Lee
and Jean Zinn-Justin completed the
demonstration that renormalization does not spoil the cancellation of unphysical
singularities in these theories.
Lee also made a major contribution to
the application of this formalism to unified theories of the weak and
electromagnetic interactions. His talk at the "Rochester" conference
at Fermilab in
1972 and his review article with Ernest Abers have been instrumental in
introducing physicists to this subject.
Spurred by the discovery of neutral
currents in 1973, Lee along with Mary K. Gaillard and Jonathan L. Rosner
undertook a systematic survey of the experimental signatures of
charmed mesons and baryons. Their report was circulated
shortly before the discovery in November 1974 of the J/ψ particle, and
immediately became the bible that guided subsequent experimental work. Even
before the discovery of the J/ψ, Lee and Gaillard had used gauge-theory
calculations of the KL - KS mass difference and
the KL → γ&gamma
decay rate to argue that the c-quark mass would have to be about 1.5 GeV or less,
a prediction that appears to have been strikingly confirmed by the observed mass
of the J/ψ. Lee and his Fermilab colleagues
were among those who most actively
elaborated and sharpened the theoretical understanding of the new hadrons.
Lee's decision to move permanently to Fermilab was a declaration of his faith in
the laboratory and of his recognition of unity of theory and experiment.
His brilliance, dedication, and deep understanding — not only of physics but
of human nature — added immeasurably to the style and standards of a
laboratory. He attracted other outstanding people to the laboratory, and
made of it a
world center of theory as well as of experiment. He was a wise and
trusted counselor to many experimentalists.
At the time of his death, Lee was in the midst of a period of enormous creativity.
In the last six months of life he had explored the problems of CP violation, of
lepton-number nonconservation, and of the high-energy limit of weak
gauge theories, and had formulated a theory based on the enlarged gauge
group SU(3)⊗U(1). He was just beginning a program of research on
cosmology and was delighted with this opportunity to move into yet another field.
Lee felt a strong sense of gratitude to older physicists who had
helped to advance his career, and he in turn took every
possible opportunity to help the young physicists of the next generation to
make their way in research. To him, the advance of physics was a common
enterprise, in which the contributions of all deserved respect and
encouragement. He will be keenly missed by the large number of physicists
who learned so much from his work, and most poignantly, by those of us who
had the privilege to know him and work with him.
Chris Quigg, Fermi National Accelerator
Steven Weinberg, Harvard University