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Encyclopedia > Pair production

Pair production refers to the creation of an elementary particle and its antiparticle, usually from a photon (or another neutral boson). This is allowed, provided there is enough energy available to create the pair – at least the total rest mass energy of the two particles – and that the situation allows both energy and momentum to be conserved (though not necessarily on shell). All other conserved quantum numbers (angular momentum, electric charge) of the produced particles must sum to zero — thus the created particles shall have opposite values of each (for instance, if one particle has strangeness +1 then another one must have strangeness −1). In particle physics, an elementary particle or fundamental particle is a particle not known to have substructure; that is, it is not made up of smaller particles. ... Corresponding to each kind of particle, there is an associated antiparticle with the same mass and opposite charges. ... The word light is defined here as electromagnetic radiation of any wavelength; thus, X-rays, gamma rays, ultraviolet light, microwaves, radio waves, and visible light are all forms of light. ... In particle physics, bosons, named after Satyendra Nath Bose, are particles having integer spin. ... Energy E = mc^2 of mass m. ... In physics, particularly in classical field theory, configurations of a physical system that satisfy classical equations of motion are called on shell, and those that do not are called off shell. ... Gyroscope. ... Electric charge is a fundamental conserved property of some subatomic particles, which determines their electromagnetic interactions. ... In particle physics, strangeness is the number of anti-strange quarks minus the number of strange quarks in a particle. ...

In nuclear physics, this occurs when a high-energy photon interacts with an atomic nucleus, allowing it to produce an electron and a positron without violating conservation of momentum. Since the momentum of the initial photon must be absorbed by something, pair production cannot occur in empty space out of a single photon; the nucleus is needed to conserve both momentum and energy. Nuclear physics is the branch of physics concerned with the nucleus of the atom. ... The word light is defined here as electromagnetic radiation of any wavelength; thus, X-rays, gamma rays, ultraviolet light, microwaves, radio waves, and visible light are all forms of light. ... A semi-accurate depiction of the helium atom. ... The Electron is a fundamental subatomic particle that carries an electric charge. ... The first detection of the positron in 1932 by Carl D. Anderson The positron is the antiparticle or the antimatter counterpart of the electron. ... In physics, a conservation law states that a particular measurable property of an isolated physical system does not change as the system evolves. ...

Pair production is the chief method by which energy from gamma rays is observed in condensed matter. The photon need only have a total energy of twice the rest mass(me) of an electron (1.022 MeV) for this to occur as described above; if it is much more energetic, heavier particles may also be produced. These interactions were first observed in Patrick Blackett's counter-controlled bubble chamber, leading to the 1948 Nobel Prize in Physics. This article is about electromagnetic radiation. ... In physics, matter is commonly defined as the substance of which physical objects are composed, not counting the contribution of various energy or force-fields, which are not usually considered to be matter per se (though they may contribute to the mass of objects). ... An electronvolt (symbol: eV) is the amount of energy gained by a single unbound electron when it falls through an electrostatic potential difference of one volt. ... Patrick Maynard Stuart Blackett, Baron Blackett (November 18, 1897&#8212;July 13, 1974) was a British experimental physicist known for his work on cloud chambers, cosmic rays, and paleomagnetism. ... A bubble chamber A bubble chamber is a vessel filled with a superheated transparent liquid used to detect electrically charged particles moving through it. ... Hannes AlfvÃ©n (1908â€“1995) accepting the Nobel Prize for his work on magnetohydrodynamics [1]. List of Nobel Prize laureates in Physics from 1901 to the present day. ...

In semiclassical general relativity, pair production is also invoked to explain the Hawking radiation effect. According to quantum mechanics, at short scales short-lived particle-pairs are constantly appearing and disappearing (see quantum foam); in a region of strong gravitational tidal forces, the two particles in a pair may sometimes be wrenched apart before they have a chance to mutually annihilate. When this happens in the region around a black hole, one particle may escape, with its antiparticle being captured by the hole. In physics, the adjective semiclassical has different precise meanings depending on the context. ... General relativity (GR) is the geometrical theory of gravitation published by Albert Einstein in 1915. ... In physics, Hawking radiation is thermal radiation thought to be emitted by black holes due to quantum effects. ... Fig. ... This article needs to be cleaned up to conform to a higher standard of quality. ... The tidal force is a secondary effect of the force of gravity and is responsible for the tides. ... Annihilation occurs when a particle collides with an antiparticle. ... A black hole is an object predicted by general relativity[1] with a gravitational field so strong that nothing can escape it â€” not even light. ...

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 Pair production - Wikipedia, the free encyclopedia (355 words) Pair production refers to the creation of an elementary particle and its antiparticle, usually from a photon (or another neutral boson). Pair production is the chief method by which energy from gamma rays is observed in condensed matter. In semiclassical general relativity, pair production is also invoked to explain the Hawking radiation effect.
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