Experiments with Antimatter: the Physics of Positrons and Antiprotons


Dr. Giulio Stancari
Idaho State University and Jefferson National Lab


The existence of antimatter was postulated theoretically by Dirac in 1931 after developing a relativistic quantum equation for the electron. The first positrons were observed by Anderson in cosmic rays in 1932, and the first observed antiprotons were produced artificially by Segr´e and collaborators at the Bevatron in 1955. Fast antihydrogen atoms were produced at CERN and at Fermilab in the 1990’s, and cold antihydrogen has been studied at CERN since 2002. In this seminar, I will describe how positrons and antiprotons are produced and used. Current research topics will also be discussed, such as the design of a positron source for the CEBAF accelerator at Jefferson Lab; attempts to produce polarized beams of antiprotons; and the physics of proton-antiproton annihilations at relativistic energies.