Oreste Piccioni ( born 24.10.1915)-an experimental physicist. He was born in Siena (Italy). He graduated from the University of Rome (1938) and worked there in 1938–45. In 1946—48 he was at the Massachusetts Institute of Technology, and in 1948 —60 at the Brookhaven National Laboratory. From 1960 he has been professor at the University of California at San Diego.
His research was in nuclear physics, elementary particle physics, cosmic-ray physics and electronic systems for nuclear research. In 1947, together with M. Conversi and E. Pancini, he proved experimentally that muons are not strongly interacting particles. In 1955, with A. Pais, he proposed an experiment in which the properties of neutral kaons should show themselves clearly (the Pais — Piccioni experiment), predicted oscillations in a beam of neutral kaons and the regeneration effect of K01. He measured the mass difference of the K01- and K02-mesons (the Piccioni experiment). In 1956, together with others, he discovered the antineutron in the process of charge exchange of antiprotons.
His research was in nuclear physics, elementary particle physics, cosmic-ray physics and electronic systems for nuclear research. In 1947, together with M. Conversi and E. Pancini, he proved experimentally that muons are not strongly interacting particles. In 1955, with A. Pais, he proposed an experiment in which the properties of neutral kaons should show themselves clearly (the Pais — Piccioni experiment), predicted oscillations in a beam of neutral kaons and the regeneration effect of K01. He measured the mass difference of the K01- and K02-mesons (the Piccioni experiment). In 1956, together with others, he discovered the antineutron in the process of charge exchange of antiprotons.