Definition of antiparticle in US English:



  • A subatomic particle having the same mass as a given particle but opposite electric or magnetic properties. Every kind of subatomic particle has a corresponding antiparticle, e.g. the positron has the same mass as the electron but an equal and opposite charge.

    • ‘Some neutral particles such as photons are their own antiparticles, while others like neutrons have antiparticles with opposite magnetic moments.’
    • ‘One can imagine atoms that are made of antiparticles: antiprotons, antineutrons, and positrons.’
    • ‘Positively charged beta particles, the antiparticle of electrons, are called positrons.’
    • ‘At about one second into the life of the universe, the majority of existing particles and antiparticles had been destroyed to produce photons of electromagnetic radiation.’
    • ‘Note that subatomic particles sometimes have antiparticles, with opposite charge and spin, that are the same ones going backwards in time.’