Lev Borisovich Okun is a Russian theoretical physicist.
He was born in Sukhinichi in 1929 in the Soviet Union, and graduated from Moscow Mechanical Institute in 1953 where he was a student of Arkady Migdal and later a graduate student of Isaak Pomeranchuk. He has worked since 1954 at the Institute for Theoretical and Experimental Physics in Moscow and has published some 300 papers, and several books, on the theory of elementary particles.
Okun introduced the term "hadron" in a plenary talk at the 1962 International Conference on High Energy Physics. In this talk he said:
Not withstanding the fact that this report deals with weak interactions, we shall frequently have to speak of strongly interacting particles. These particles pose not only numerous scientific problems, but also a terminological problem. The point is that "strongly interacting particles" is a very clumsy term which does not yield itself to the formation of an adjective. For this reason, to take but one instance, decays into strongly interacting particles are called non-leptonic. This definition is not exact because "non-leptonic" may also signify "photonic". In this report I shall call strongly interacting particles "hadrons", and the corresponding decays "hadronic" (the Greek ἁδρός signifies "large", "massive", in contrast to λεπτός which means "small", "light"). I hope that this terminology will prove to be convenient. – Lev B. Okun, 1962
He has served as a member of the Scientific Policy Committees of CERN, SSC and DESY. He is a member of the Russian Academy of Sciences and the Academia Europaea, an honorary member of the New York Academy of Sciences, and a Fellow of the Institute of Physics.
He is held in high regard by colleagues such as Murray Gell-Mann.