annihilation


annihilation
/euh nuy'euh lay"sheuhn/, n.
1. the act or an instance of annihilating.
2. the state of being annihilated; extinction; destruction.
3. Physics.
a. Also called pair annihilation. the process in which a particle and antiparticle unite, annihilate each other, and produce one or more photons. Cf. positronium.
b. the conversion of rest mass into energy in the form of electromagnetic radiation.
[1630-40; ( < F) < LL annihilation- (s. of annihilatio). See ANNIHILATE, -ION]

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In physics, a reaction in which a particle and its antiparticle (see antimatter) collide and disappear.

The annihilation releases energy equal to the original mass m multiplied by the square of the speed of light c, or E = mc2, in accordance with Albert Einstein's special theory of relativity. The energy can appear directly as gamma rays or can convert back to particles and antiparticles (see pair production).

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      in physics, reaction in which a particle (subatomic particle) and its antiparticle collide and disappear, releasing energy. The most common annihilation on Earth occurs between an electron and its antiparticle, a positron. A positron, which may originate in radioactive decay (radioactivity) or, more commonly, in the interactions of cosmic rays (cosmic ray) in matter, usually combines briefly with an electron to form a quasi-atom called positronium. The quasi-atom is composed of the two particles spinning around each other before they annihilate. After the annihilation, two or three gamma rays (gamma ray) radiate from the point of collision.

      The amount of energy (E) produced by annihilation is equal to the mass (m) that disappears multiplied by the square of the speed of light in a vacuum (c)—i.e., E = mc2. Thus, annihilation is an example of the equivalence of mass and energy and a confirmation of the theory of special relativity, which predicts this equivalence. (See Einstein's mass-energy relation.)

      At the higher energies characteristic of particle-antiparticle collisions taking place in colliding-beam storage ring particle accelerators or in the big-bang model (Cosmos) of the early universe, the annihilation energy is sufficient to create heavier particles and their antiparticles, such as muons (muon) and antimuons or quarks (quark) and antiquarks. Combinations of these latter particles and antiparticles, in turn, form mesons (meson)—including pi-mesons and K-mesons—which are classified within the hadron (subatomic particle) group of subatomic particles. Other annihilation reactions also occur. Nucleons (nucleon) (protons and neutrons), for example, annihilate antinucleons (antiprotons and antineutrons), and the energy is also carried away in the form of particles such as pi-mesons and K-mesons and their corresponding antiparticles.

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Universalium. 2010.

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  • annihilation — [ aniilasjɔ̃ ] n. f. • XVIe; anichilation XIVe; lat. ecclés. annihilatio → annihiler 1 ♦ Vx Anéantissement, annulation. L annihilation de ses projets. 2 ♦ Mod. Phys. Transformation d une paire (particule et antiparticule) en un rayonnement de… …   Encyclopédie Universelle

  • Annihilation — is defined as total destruction or complete obliteration of an object; [ [http://dictionary.reference.com/search?r=2 q=Annihilation Dictionary Definition] (2006) Dictionary.com.] having its root in the Latin nihil (nothing). A literal translation …   Wikipedia

  • Annihilation — (lat.: annihilatio „das Zunichtemachen“) bedeutet in der Physik die gegenseitige Vernichtung zweier entgegengesetzter Erscheinungen. Inhaltsverzeichnis 1 Elementarteilchenphysik 1.1 Hochenergiephysik Forschung 1.2 Positron Elektron Vernichtung in …   Deutsch Wikipedia

  • Annihilation — An*ni hi*la tion, n. [Cf. F. annihilation.] 1. The act of reducing to nothing, or nonexistence; or the act of destroying the form or combination of parts under which a thing exists, so that the name can no longer be applied to it; as, the… …   The Collaborative International Dictionary of English

  • annihilation — (n.) 1630s, from M.Fr. annihilation (restored from O.Fr. anichilacion, 14c.), or directly from L.L. annihilationem (nom. annihilatio), noun of action from pp. stem of annihilare (see ANNIHILATE (Cf. annihilate)) …   Etymology dictionary

  • Annihĭlation — (v. lat.), Nichtigerklärung, Aufhebung; daher annihiliren …   Pierer's Universal-Lexikon

  • Annihilation — (lat.), Nichtigkeitserklärung; annihilieren, vernichten, für nichtig erklären …   Kleines Konversations-Lexikon

  • Annihilation — См. Аннигиляция Термины атомной энергетики. Концерн Росэнергоатом, 2010 …   Термины атомной энергетики

  • annihilation — index abolition, assassination, demise (death), destruction, dissolution (termination), homicide …   Law dictionary

  • annihilation — ANNIHILATION. s. f. (On pron. les N.) Terme didactique. Anéantissement …   Dictionnaire de l'Académie Française 1798

  • Annihilation — Cette page d’homonymie répertorie les différents sujets et articles partageant un même nom. Sur les autres projets Wikimedia : « Annihilation », sur le Wiktionnaire (dictionnaire universel) l’annihilation entre une particule et son …   Wikipédia en Français


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