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A Feynman diagram of a positron and an electron annihilating into a photon which then decays back into a positron and an electron.

Annihilation is defined as "total destruction" or "complete obliteration" of an object;^[1] having its root in the Latin nihil (nothing). A literal translation is "to make into nothing". Annihilation is the opposite of exnihilation, which means "to create something out of nothing". Look up annihilation in Wiktionary, the free dictionary. ... Image File history File links Wikitext. ... Image File history File links Electron-positron-annihilation. ... Image File history File links Electron-positron-annihilation. ... In this Feynman diagram, an electron and positron annihilate and become a quark-antiquark pair. ... The first detection of the positron in 1932 by Carl D. Anderson The positron is the antiparticle or the antimatter counterpart of the electron. ... For other uses, see Electron (disambiguation). ...

In physics, the word is used to denote the process that occurs when a subatomic particle collides with its respective antiparticle. Since energy and momentum must be conserved, the particles are not actually made into nothing, but rather into new particles. Antiparticles have exactly opposite additive quantum numbers from particles, so the sums of all quantum numbers of the original pair are zero. Hence, any set of particles may be produced whose total quantum numbers are also zero as long as conservation of energy and conservation of momentum are obeyed. A magnet levitating above a high-temperature superconductor demonstrates the Meissner effect. ... Helium atom (schematic) Showing two protons (red), two neutrons (green) and two electrons (yellow). ... Corresponding to most kinds of particle, there is an associated antiparticle with the same mass and opposite charges. ... Quantum numbers describe values of conserved quantity in the dynamics of the quantum system. ... Look up conservation of energy in Wiktionary, the free dictionary. ... In physics, a conservation law states that a particular measurable property of an isolated physical system does not change as the system evolves. ...

During a low-energy annihilation, photon production is favored, since these particles have no rest mass. However, high-energy particle colliders produce annihilations where a wide variety of exotic heavy particles are created. In modern physics the photon is the elementary particle responsible for electromagnetic phenomena. ... A particle accelerator uses electric fields to propel charged particles to great energies. ...

Examples of annihilation

An example of a virtual pion pair which influences the propagation of a kaon causing a neutral kaon to mix with the antikaon. This is an example of renormalization in quantum field theory— the field theory being necessary because the number of particles changes from one to two and back again.

When a low-energy electron annihilates a low-energy positron (anti-electron), they can only produce two or more gamma ray photons, since the electron and positron do not carry enough mass-energy to produce heavier particles. However, if one or both particles carry a larger amount of kinetic energy, various other particle pairs can be produced. See electron-positron annihilation. Image File history File links K0-Kobar oscillation through a two pion intermediate state File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... In particle physics, pion (short for pi meson) is the collective name for three subatomic particles: π0, π+ and π−. Pions are the lightest mesons and play an important role in explaining low-energy properties of the strong nuclear force. ... In particle physics, Kaons (also called K-mesons and denoted K) are a group of four mesons distinguished by the fact that they carry a quantum number called strangeness. ... Figure 1. ... Quantum field theory (QFT) is the quantum theory of fields. ... For other uses, see Electron (disambiguation). ... The first detection of the positron in 1932 by Carl D. Anderson The positron is the antiparticle or the antimatter counterpart of the electron. ... This article is about electromagnetic radiation. ... In modern physics the photon is the elementary particle responsible for electromagnetic phenomena. ... E=mc² is a physical equation, first given by Albert Einstein in his 1905 paper Does the Inertia of a Body Depend Upon Its Energy Content? (Ist die Trägheit eines Körpers von seinem Energieinhalt abhängig?), one of the articles now known as his Annus Mirabilis Papers. ... Naturally occurring electron-positron annihilation as a result of beta plus decay Feynman Diagram of Electron-Positron Annihilation Electron-positron annihilation occurs when an electron and a positron (the electrons anti-particle) collide. ...

The annihilation (or decay) of an electron-positron pair into a single photon, e⁺ + e^- → γ, cannot occur because energy and momentum would not be conserved in this process. The reverse reaction is also impossible for this reason, except in the presence of another particle that can carry away the excess energy and momentum. However, in quantum field theory this process is allowed as an intermediate quantum state. Some authors justify this by saying that the photon exists for a time which is short enough that the violation of energy conservation can be accommodated by the uncertainty principle. Others choose to assign the intermediate photon a non-zero mass. (The mathematics of the theory are unaffected by which view is taken.) This opens the way for virtual pair production or annihilation in which a one-particle quantum state may fluctuate into a two-particle state and back again.^{[citation needed]} These processes are important in the vacuum state and renormalization of a quantum field theory. It also allows neutral particle mixing through processes such as the one pictured here. Quantum field theory (QFT) is the quantum theory of fields. ... Look up conservation of energy in Wiktionary, the free dictionary. ... In quantum physics, the outcome of even an ideal measurement of a system is not deterministic, but instead is characterized by a probability distribution, and the larger the associated standard deviation is, the more uncertain we might say that that characteristic is for the system. ... In quantum field theory, the vacuum state, usually denoted , is the element of the Hilbert space with the lowest possible energy, and therefore containing no physical particles. ... Figure 1. ...

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