Pair production is a quantum process where a high-energy photon (a particle of light) is converted into a particle-antiparticle pair, specifically an electron and its antimatter counterpart, the positron.
How It Happens:
- When a photon with energy greater than 1.022 million electron volts (MeV) passes near a nucleus or another charged particle, it can transform into an electron and a positron.
- The presence of a nearby nucleus is essential to conserve momentum during the process.
- The photon’s energy is converted into the mass and kinetic energy of the two particles, in accordance with Einstein’s equation E=mc².
Key Points:
- The electron and positron have equal mass but opposite electric charge.
- After formation, the positron will eventually annihilate with an electron, producing photons.
- Pair production is a clear demonstration of the equivalence of mass and energy and the quantum nature of particles.
Applications and Importance:
- Occurs naturally in high-energy cosmic events and particle accelerators.
- Used in positron emission tomography (PET) scans in medical imaging.
- Helps physicists explore particle-antiparticle interactions and fundamental symmetries.
Pair production shows how energy can create matter, bridging the worlds of light and particles in the quantum universe.