Particles and Antiparticles

Unit 1, Lesson 2

Learning outcomes:

  • To know what is the difference between particles and antiparticles
  • To be able to explain what annihilation is
  • To be able to explain what pair production is

Antimatter

British Physicist Paul Dirac predicted a particle of equal mass to an electron but of opposite charge. This particle is called a positron and is the electron’s antiparticle.

Every particles has its own antiparticle. An antiparticle has the same mass as the particle version but has opposite charge. An antiproton has a negative charge, an antielectron has a positive charge, but an antineutron is uncharged just like the particle version.

American Physicist Carl Anderson observed the positron in a cloud chamber, backing up Dirac's theory.