A theory proposed in i928 by the Cambridge University physicist Paul Dirac that predicted a partner for the electron that would have a positive charge to counter the electrons negative charge. Dirac was the first to speculate about the existence and behavior of subatomic particles consistent with both the special theory of relativity and with quantum mechanics. Experiments conducted in 1932 confirmed Dirac’s theory with the discovery of the positron, and as a result, Dirac won the 1933 Nobel Prize.
Theoretical physicists believe that for every type of particle there may exist an antiparticle with all its properties reversed each a mirror image of the other but only a very few antiparticles have been produced experimentally, and the existence of a few others can only be inferred from observations of high energy nuclear reactions. When a particle meets its antiparticle then annihilation energy is produced and the particles are destroyed in the process.