24.3 Antiparticles, hadrons and leptons

• Every particle has a corresponding antiparticle, and if the two meet they completely destroy each other in a process called annihilation; they are converted into a high-energy pair of photons.
• The antiparticle of the electron is the positron, others are antiproton, antineutron and antineutrino.
• There are four fundamental forces, Strong and Weak nuclear, electromagnetic and gravitational.
• Strong nuclear force is experienced by nucleons, Electromagnetic force is experienced by static and moving charged particles, Weak nuclear is responsible for beta-decay and gravitational is experienced by all particles with mass.
• A fundamental particle has no internal structure and hence cannot be divided into smaller bits.
• Hadrons are particles and antiparticles that are affected by the strong nuclear force. Hadrons decay by the weak nuclear force.
• Leptons are particles and antiparticles that are not affected by the strong nuclear force, like electrons, neutrinos and muons.