positron

A positron is the antimatter-equivalent of an electron (i.e., an antielectron), with the same mass but opposite electrical charge. It is a stable lepton that can be produced by pair production, but unlike antiprotons and antineutrons, is also produced by "normal-matter" nuclear reactions, such as fusion and beta decay. The term beta particle refers to either an electron or a positron produced by beta decay.

Like any particle/antiparticle pair, the meeting of a positron and an electron results in annihilation, which produces two photons with whose photon energies sum to the kinetic energy and rest energy of the positron and electron, minimally 1.022 MeV. This is the inverse of pair production.