Richard Henry Dalitz (28 February 1925 – 13 January 2006) was an Australian physicist known for his work in quantum mechanics.
Born Dimboola, Victoria near Melbourne, Dalitz studied physics and mathematics at Melbourne University before moving to the United Kingdom in 1946, starting his PhD research at the University of Cambridge. After two years he took up a one year post at the University of Bristol, and then joined Rudolf Peierls' group at Birmingham University, completing his thesis demonstrating that the electrically neutral pion could decay into a photon and an electron-positron pair, now known as a Dalitz pair.
Dalitz moved to Cornell University in 1953, and in 1954 he introduced the Dalitz plot. He then became a professor at the Enrico Fermi Institute in Chicago from 1956 to 1963, when he moved to the University of Oxford as a Royal Society research professor, although keeping a connection with Chicago until 1966. He retired in 1990.
Dalitz was made a Fellow of the Royal Society in 1960. He was a close friend of John Clive Ward the creator of the Ward Identities. When in Oxford he found out that his name was of Sorbian origin and with the help of the Oxford scholar Dr. Gerald Stone learned Sorbian and often visited Budushin. He became fluent in the language and was honored by articles in Sorbian journals.