pósitron

The positron, also known as the antiparticle of the electron, is a subatomic particle with a positive electric charge equal in magnitude to that of the electron. Its symbol is e+ or β+. Discovered by Carl D. Anderson in 1932 in cosmic ray experiments, the positron was the first antiparticle to be found. It has the same mass as the electron.

When a positron encounters an electron, they annihilate each other, producing two gamma-ray photons. This process is a fundamental example of matter-antimatter annihilation. Positrons are produced in several natural radioactive decay processes, such as beta-plus decay, where a proton within an atomic nucleus transforms into a neutron, emitting a positron and an electron neutrino. They are also generated in high-energy particle collisions and by certain astrophysical phenomena.

While positrons are unstable in ordinary matter due to annihilation, they have practical applications. Positron emission tomography (PET) is a medical imaging technique that uses radiotracers that emit positrons. When these positrons annihilate with electrons in the body, they produce gamma rays that are detected by the PET scanner, allowing for the visualization of metabolic processes. The study of positrons has been crucial in advancing our understanding of particle physics and the fundamental nature of matter.