Antimatter (OCR A Level Physics)

Antimatter

• The universe is made up of matter particles (protons, neutrons, electrons etc.)

• All matter particles have antimatter counterparts

  • Antimatter particles are identical to their matter counterpart but with the opposite charge

• This means if a particle is positive, its antimatter particle is negative and vice versa

• Common matter-antimatter pairs are shown in the diagram below:

Matter-Antimatter Table

• Apart from electrons, the corresponding antiparticle pair has the same name with the prefix ‘anti-’ and a line above the corresponding matter particle symbol

• A neutral particle, such as a neutron or neutrino, is its own antiparticle

Properties of Antimatter

• Although antimatter particles have the opposite charges to their matter counterparts, they still have identical mass and rest mass-energy

  • The rest mass-energy of a particle is the energy equivalent to the mass of the particle at rest

• The datasheet provides the masses in kg and rest-mass energies in MeV for a proton, neutron, electron and neutrino

• These masses are identical for their corresponding antiparticles (antiproton, antineutron, positron and antineutrino respectively)

Mass & Rest Mass Energy Table