Kazuhiko Nishijima

Kazuhiko Nishijima
Born	4 October 1926 Tsuchiura, Japan
Died	15 February 2009 Tokyo, Japan
Nationality	Japanese
Alma mater	University of Tokyo Osaka University
Known for	Strangeness Gell-Mann–Nishijima formula
Scientific career
Fields	Theoretical physics Particle physics
Institutions	University of Tokyo Princeton University University of Illinois at Urbana-Champaign

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-Mann, the Gell-Mann–Nishijima formula, and the concept of strangeness, which he called the "eta-charge" or "η-charge", after the eta meson (
η
).^[1][2] He died of leukemia on 15 February 2009 at the age of 82.^[1][3]

Nishijima was born in Tsuchiura, Japan on 4 October 1926.^[3] He obtained his diploma in physics at the Imperial 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]

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

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-Mann^[4] and George Zweig^[5][6] 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 of Advanced Study at Princeton University.^[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 time of his death. His last subjects of research were color confinement and noncommutative quantum field theory.^[3]

• Nishijima, K (1963). Fundamental Particles. W. A. Benjamin. OCLC 536472.
• Nishijima, K (1998) [1974]. Fields and Particles: Field Theory and Dispersion Relations (4th ed.). Benjamin Cummings. ISBN 0805373993.

• Nishina Memorial Prize^[3]
• Japan Academy Prize^[3]
• Order of Culture of Japan^[3]
• Guggenheim Fellow^[7]

• Kawarabayashi, K (1987). Wandering in the Fields: Festschrift for Professor Kazuhiko Nishijima on the Occasion of His Sixtieth Birthday. World Scientific. ISBN 9971503638. {{cite book}}: Unknown parameter |editorfirst= ignored (|editor-first= suggested) (help); Unknown parameter |editorlast= ignored (|editor-last= suggested) (help)