Susumu Okubo

was a Japanese theoretical physicist at the University of Rochester. Ōkubo worked primarily on elementary particle physics. He is famous for the Gell-Mann–Okubo mass formula for mesons and baryons in the quark model; this formula correctly predicts the relations of masses of the members of SU(3) multiplets in terms of hypercharge and isotopic spin. Ōkubo died in July 2015.

In 1976 Ōkubo received the Nishina Memorial Prize in Japan and in 2006 the Wigner Medal. In 1966 he was a Guggenheim Fellow and in 1969 a Ford Fellow. He was a member of the American Physical Society and the American Mathematical Society.

Works Introduction to Octonion and Other Non-Associative Algebras in Physics. Cambridge University Press, 1995 'Lie Groups and Lie Algebras for Physicists,' with Ashok Das. World Scientific and Hindustan Book Agency, October 2014.