antiparticle

In nuclear physics, a particle corresponding in mass and properties to a given elementary particle but with the opposite electrical charge, magnetic properties, or coupling to other fundamental forces. For example, an electron carries a negative charge whereas its antiparticle, the positron, carries a positive one. When a particle and its antiparticle collide, they destroy each other, in the process called ‘annihilation’, their total energy being converted to lighter particles and/or photons. A substance consisting entirely of antiparticles is known as antimatter.