Owen Chamberlain (b. July 10, 1920) is an American physicist. He shared the Nobel Prize in Physics for 1959 with his collaborator Emilio Segrč for their discovery of the anti-proton, a fundamental particle.
Born in San Francisco, Chamberlain studied physics at Dartmouth College (A.B. 1941) and the University of California, Berkeley until the outbreak of World War II. He joined the Manhattan Project in 1942, where he worked with Segrč, both at Berkeley and in Los Alamos, New Mexico. He married Beatrice Babette Copper in 1943, with whom he had four children.
In 1946, after the war, Chamberlain continued with his doctorate work at the University of Chicago under legendary physicist Enrico Fermi. Fermi acted as an important guide and mentor for Chamberlain, encouraging him to leave behind the more prestigious theoretical physics for experimental physics, for which Chamberlain had a particular aptitude.
In 1948, Chamberlain returned to Berkeley as a member its faculty (promoted to professor of physics in 1958), where he, Segrč, and other physicists investigated proton-proton scattering. In 1955, a series of proton scattering experiments led to the discovery of the anti-proton, a particle exactly like a proton except negatively charged. Chamberlain's later research work included the Time Projection Chamber (TPC), and work at the Stanford Linear Accelerator Center (SLAC).
Chamberlain was also politically active on issues of peace and social justice, and spoke out against the Vietnam War. He was an influential member of Scientists for Sakharov, Orlov, and Shcharansky, three physicists of the Soviet Union imprisoned for their political beliefs. In the 1980s, he helped found the nuclear freeze movement.
Chamberlain was diagnosed with Parkinson's disease in 1985, and retired from teaching in 1989.