Photo from the Nobel Foundation archive.
Carl David Anderson
Born: 3 September 1905, New York, NY, USA
Died: 11 January 1991, San Marino, CA, USA
Affiliation at the time of the award: California Institute of Technology (Caltech), Pasadena, CA, USA
Prize motivation: "for his discovery of the positron."
Prize share: 1/2
In developing quantum mechanical theory, Paul Dirac predicted that all matter has a kind of mirror image - antimatter. A particle and its antiparticle, if charged, should have opposite charges. By studying the tracks of cosmic ray particles in a cloud chamber, in 1932 Carl Anderson discovered a positively-charged particle with a mass seemingly equal to that of an electron. Carl Anderson's particle was the first antiparticle proven by experiment and was named a "positron".