Antiparticle

Name:
Antiparticle
Detailed information:
(antimatter).Any of several species of subatomic particles that are identical in mass to ordinary particles, but opposite in electrical charge or (in the case of the neutron) in magnetic moment. Thus, a positron is an electron with a positive charge, an antiproton is a proton with a negative charge, and an antineutron has no charge but has a magnetic moment opposite to that of a neutron. A photon is its own antiparticle. When an antiparticle collides with its opposite particle (e.g., a collision of an electron and a positron) both particles are annihilated and their masses are converted to photons of equivalent energy. The same is true of other subatomic particles (neutrinos, mesons, etc.) some of which are fantastically short-lived (of the order of billionths of a second).