was a Japanese theoretical physicist at the

University of Rochester The University of Rochester is a private university, private research university in Rochester, New York, United States. It was founded in 1850 and moved into its current campus, next to the Genesee River in 1930. With approximately 30,000 full ...

. Ōkubo worked primarily on

elementary particle physics Particle physics or high-energy physics is the study of fundamental particles and forces that constitute matter and radiation. The field also studies combinations of elementary particles up to the scale of protons and neutrons, while the stud ...

. He is famous for the

Gell-Mann–Okubo mass formula In physics, the Gell-Mann–Okubo mass formula provides a sum rule for the masses of hadrons within a specific multiplet, determined by their isospin (''I'') and strangeness (or alternatively, hypercharge) :M = a_0 + a_1 Y + a_2 \left I \left( I ...

for

meson In particle physics, a meson () is a type of hadronic subatomic particle composed of an equal number of quarks and antiquarks, usually one of each, bound together by the strong interaction. Because mesons are composed of quark subparticles, the ...

s and

baryon In particle physics, a baryon is a type of composite particle, composite subatomic particle that contains an odd number of valence quarks, conventionally three. proton, Protons and neutron, neutrons are examples of baryons; because baryons are ...

s in the

quark model In particle physics, the quark model is a classification scheme for hadrons in terms of their valence quarks—the quarks and antiquarks that give rise to the quantum numbers of the hadrons. The quark model underlies "flavor SU(3)", or the Eig ...

; this formula correctly predicts the relations of masses of the members of SU(3) multiplets in terms of

hypercharge In particle physics, the hypercharge (a portmanteau of hyperonic and charge (physics), charge) ''Y'' of a subatomic particle, particle is a quantum number conserved under the strong interaction. The concept of hypercharge provides a single charg ...

and isotopic spin. Ōkubo died in July 2015. Ōkubo began study at the

University of Tokyo The University of Tokyo (, abbreviated as in Japanese and UTokyo in English) is a public research university in Bunkyō, Tokyo, Japan. Founded in 1877 as the nation's first modern university by the merger of several pre-westernisation era ins ...

in 1949 and received his bachelor's degree there in 1952. He became a graduate student at the

in 1954, where he earned his PhD in 1958 with David Feldman as thesis advisor. Afterwards, he was a postdoc in 1959/60 at the

University of Naples The University of Naples Federico II (; , ) is a public university, public research university in Naples, Campania, Italy. Established in 1224 and named after its founder, Frederick II, Holy Roman Emperor, Frederick II, it is the oldest public, s ...

, in 1960/61 at

CERN The European Organization for Nuclear Research, known as CERN (; ; ), is an intergovernmental organization that operates the largest particle physics laboratory in the world. Established in 1954, it is based in Meyrin, western suburb of Gene ...

, and then in 1962 began researching again at the University of Rochester, where he became a professor in 1964 and retired in 1996 as an emeritus professor.

Awards

In 2005 he received the

Sakurai Prize The J. J. Sakurai Prize for Theoretical Particle Physics, also commonly referred to as just the Sakurai Prize, is a prize awarded by the American Physical Society. It is presented annually at the Society's April meeting and honors "outstanding a ...

from the

American Physical Society The American Physical Society (APS) is a not-for-profit membership organization of professionals in physics and related disciplines, comprising nearly fifty divisions, sections, and other units. Its mission is the advancement and diffusion of ...

; ''"For groundbreaking investigations into the pattern of hadronic masses and decay rates, which provided essential clues into the development of the quark model, and for demonstrating that CP violation permits partial decay rate asymmetries"''.Susumu Okubo - 2005 J. J. Sakurai Prize Winner
/ref> In 1976 Ōkubo received the Nishina Memorial Prize in Japan and in 2006 the

Wigner Medal The International Colloquium on Group Theoretical Methods in Physics (ICGTMP) is an academic conference devoted to applications of group theory to physics. It was founded in 1972 by Henri Bacry and Aloysio Janner. It hosts a colloquium every tw ...

. In 1966 he was a

Guggenheim Fellow Guggenheim Fellowships are grants that have been awarded annually since by the John Simon Guggenheim Memorial Foundation, endowed by the late Simon and Olga Hirsh Guggenheim. These awards are bestowed upon individuals who have demonstrated d ...

and in 1969 a Ford Fellow. He was a member of the American Physical Society and the

American Mathematical Society The American Mathematical Society (AMS) is an association of professional mathematicians dedicated to the interests of mathematical research and scholarship, and serves the national and international community through its publications, meetings, ...

Works

* ''Introduction to Octonion and Other Non-Associative Algebras in Physics''. Cambridge University Press, 1995

References

External links

Biography from the University of Rochester

Okubo on the discovery of the mass formula
(pdf file, 92 kB)
Scientific publications of Susumu Okubo
on

INSPIRE-HEP INSPIRE-HEP is an open access digital library for the field of high energy physics (HEP). It is the successor of the Stanford Physics Information Retrieval System (SPIRES) database, the main literature database for high energy physics since the 1 ...

{{DEFAULTSORT:Okubo, Susumu Japanese physicists 1930 births 2015 deaths J. J. Sakurai Prize for Theoretical Particle Physics recipients Japanese mathematical physicists People associated with CERN Japanese theoretical physicists Fellows of the American Physical Society University of Tokyo alumni Scientists from Tokyo Metropolis