A particle is a minute fragment or quantity of matter while particle that has the same mass as another particle but opposite charge or spin is called antiparticle. In this universe, every particle has its antimatter in equal proportion. The antiparticle is like the mirror image of a particle. So, an antiparticle has:
- Same mass as that of particle
- Opposite charge
- Spins in opposite direction.
Every type of particle has a corresponding antiparticle, for example;
- Positron is the antiparticle of the electron.
- Antiproton is the antiparticle of the proton.
- Antineutron is the antiparticle of the neutron.
- Antineutrino is the antiparticle of the neutrino.
Pair production and annihilation
When a particle and its antiparticle meet each other they annihilate(cancel) each other. Their mass is converted into energy in the form of photons. The figure below is an example of mass being converted into energy but it can also work the other way around with energy being converted into mass.
High energy photons can produce a particle and its antiparticle, this is called pair production. Example: When a gamma ray passes close to a nucleus it can interact with that nucleus forming a positron and an electron. This is known as pair production. The picture below illustrate the pair production phenomena.