# Kazuhiko Nishijima

Kazuhiko Nishijima
Born 4 October 1926
Tsuchiura, Japan
Died 15 February 2009
Tokyo, Japan
Nationality Japanese
Fields Theoretical physics
Particle physics
Institutions Osaka City University
Max Planck Institute for Physics
University of Illinois at Urbana-Champaign
University of Tokyo
Kyoto University
Chuo University
Alma mater University of Tokyo
Osaka University
Known for Strangeness
Gell-Mann–Nishijima formula

Kazuhiko Nishijima (西島 和彦 Nishijima Kazuhiko?) (4 October 1926 – 15 February 2009) was a Japanese physicist who made significant contributions to particle physics. He was professor emeritus at the University of Tokyo and Kyoto University until his death in 2009.1

He was born in Tsuchiura, Japan. He is most well known for the product of his collaboration with Murray Gell-Manncitation needed, the Gell-Mann–Nishijima formula, and the concept of strangeness, which he called the "eta-charge" or "η-charge", after the eta meson (η).12 3

## Life

Nishijima was born in Tsuchiura, Japan on 4 October 1926.3 He obtained his diploma in physics at the University of Tokyo in 1948, and his PhD from Osaka University in 1955 for his thesis on the nuclear potential.3

In 1950, while at Osaka University, Nishijima was hired by Yoichiro Nambu to work on the theory of strong interactions and of strange particles (then called V particles).3 While studying the decay of these particles, Nishijima developed, with Tadao Nakano, and independently of Murray Gell-Mann, a formula that would relate the quantum numbers of these particles, the Gell-Mann–Nishijima formula (or sometimes the NNG formula, for Nishijima, Nakano, and Gell-Mann).3

$Q = I_\text{3} + \frac{B+S}{2}$

where Q is the electric charge, I3 is the isospin projection, B is the baryon number, and S is the strangeness quantum number of the particle. This formula was pivotal for the later development of the quark model by Gell-Mann4 and George Zweig56 in 1964 (independently of each other).

From 1956 to 1958, Nishijima worked in Göttingen, Germany, upon the invitation of Werner Heisenberg.3 In 1958, he moved to the United States and joined the Institute for Advanced Study in Princeton, New Jersey.3 A year and a half later, he became a professor at the University of Illinois at Urbana–Champaign.3 In 1966, he returned to the University of Tokyo, where he founded a theoretical physics research group and served in some administrative positions.3 From 1986 until 1989 and again from 1995 until 2005, he was the president of the Nishina Memorial Foundation, a foundation that promotes physics in Japan.3

Nishijima kept active in research until near the end of his life. His last subjects of research were color confinement and noncommutative quantum field theory.3 He died of leukemia on 15 February 2009 at the age of 82.13

## References

1. ^ a b c "Particle Physicist Kazuhiko Nishijima dies at 82". The Japan Times. 18 February 2009. Retrieved 2010-07-16.
2. ^ Nishijima, K (1955). "Charge Independence Theory of V Particles". Progress of Theoretical Physics 13 (3): 285. Bibcode:1955PThPh..13..285N. doi:10.1143/PTP.13.285.
3. Nambu, Y. (2009). "Kazuhiko Nishijima". Physics Today 62 (8): 58. Bibcode:2009PhT....62h..58N. doi:10.1063/1.3206100.
4. ^ Gell-Mann, M (1964). "A Schematic Model of Baryons and Mesons". Physics Letters 8 (3): 214–215. Bibcode:1964PhL.....8..214G. doi:10.1016/S0031-9163(64)92001-3.
5. ^ Zweig, G (1964). "An SU(3) Model for Strong Interaction Symmetry and its Breaking". CERN Report No.8181/Th 8419.
6. ^ Zweig, G (1964). "An SU(3) Model for Strong Interaction Symmetry and its Breaking: II". CERN Report No.8419/Th 8412.
7. ^ "本学名誉教授の西島和彦先生が平成15年度の文化勲章を受章" (in Japanese). University of Tokyo. Retrieved 2010-07-16.
8. ^ "Kazuhiko Nishijima, Guggenheim Fellow 1965". John Simon Guggenheim Memorial Foundation. Retrieved 2009-08-18.