An electron’s antiparticle
A positron carries one unit of positive charge but has an electron’s mass, not a proton’s. Equal charge does not make different particles identical. A semiconductor hole is also distinct: it is an effective description of missing electronic occupancy, rather than a free electron antiparticle.
From theory to cosmic-ray tracks
Dirac’s relativistic electron theory provided a background for interpreting the anti-electron. Anderson identified the positron through cosmic-ray research, a discovery recognized by part of the 1936 Nobel Prize. Experimental identification depended on recorded charged-particle behaviour, rather than on assigning a positive label to a drawing.
Production and annihilation
Certain radioactive decays and energetic interactions produce positrons. An electron and positron can annihilate into other particles, commonly photons. The initial rest energy and motion contribute to the final products, while conservation laws continue to apply; annihilation is not unrestricted disappearance of physical quantities.
A testable example of antimatter
Positrons give antimatter research a concrete experimental subject and help make anti-atom formation possible. They are not fictional negative-mass matter. Experiments distinguish production, transport, detection and annihilation, because a signal from one stage does not by itself establish everything about the particle’s behaviour.