![]() Electrons moving backward in time would have a positive electric charge. įeynman, and earlier Stueckelberg, proposed an interpretation of the positron as an electron moving backward in time, reinterpreting the negative-energy solutions of the Dirac equation. Persuaded by Oppenheimer's and Weyl's argument, Dirac published a paper in 1931 that predicted the existence of an as-yet-unobserved particle that he called an "anti-electron" that would have the same mass and the opposite charge as an electron and that would mutually annihilate upon contact with an electron. Hermann Weyl in 1931 showed that the negative-energy electron must have the same mass as that of the positive-energy electron. He asserted that if it were, the hydrogen atom would rapidly self-destruct. Robert Oppenheimer argued strongly against the proton being the negative-energy electron solution to Dirac's equation. Dirac acknowledged that the proton having a much greater mass than the electron was a problem, but expressed "hope" that a future theory would resolve the issue. The paper also explored the possibility of the proton being an island in this sea, and that it might actually be a negative-energy electron. an electron with negative energy moves in an external field as though it carries a positive charge." He further asserted that all of space could be regarded as a "sea" of negative energy states that were filled, so as to prevent electrons jumping between positive energy states (negative electric charge) and negative energy states (positive charge). ĭirac wrote a follow-up paper in December 1929 that attempted to explain the unavoidable negative-energy solution for the relativistic electron. However, no such transition had yet been observed experimentally. Quantum mechanics did not allow the negative energy solution to simply be ignored, as classical mechanics often did in such equations the dual solution implied the possibility of an electron spontaneously jumping between positive and negative energy states. The positive-energy solution explained experimental results, but Dirac was puzzled by the equally valid negative-energy solution that the mathematical model allowed. Hermann Weyl then published a paper discussing the mathematical implications of the negative energy solution. The paper did not explicitly predict a new particle but did allow for electrons having either positive or negative energy as solutions. This paper introduced the Dirac equation, a unification of quantum mechanics, special relativity, and the then-new concept of electron spin to explain the Zeeman effect. In 1928, Paul Dirac published a paper proposing that electrons can have both a positive and negative charge. Positrons can be created by positron emission radioactive decay (through weak interactions), or by pair production from a sufficiently energetic photon which is interacting with an atom in a material. If this collision occurs at low energies, it results in the production of two or more photons. When a positron collides with an electron, annihilation occurs. It has an electric charge of +1 e, a spin of 1/2 (the same as the electron), and the same mass as an electron. The positron or antielectron is the antiparticle ( antimatter counterpart) of the electron. The deflection and direction of the particle's ion trail indicate that the particle is a positron. Anderson of the first positron ever identified.
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