Yoshio Koide

Yoshio Koide (born 16 May 1942 in Kanazawa, Ishikawa) is a Japanese theoretical physicist specializing in particle physics, best known for the Koide formula, a relation among the masses of the charged leptons that has drawn attention for its surprising accuracy; some physicists regard it as potentially significant and others as a numerical coincidence. He took his B.Sc. and M.Sc. at Kanazawa University in 1967 and a Doctor of Science at Hiroshima University in 1970. After posts at Hiroshima and Osaka Universities and at Kinki University, he was assistant and then associate professor at Shizuoka Women's University, and from 1987 to 2007 professor of physics at the University of Shizuoka, retiring as professor emeritus. He was a visiting researcher at CERN in 2002. He published the formula in 1982, first derived it from a composite model of quarks and leptons and later re-derived it from a family symmetry model, and with Hiroyuki Nishiura he worked on quark, lepton and neutrino mass matrix models.