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strong interaction

n. (context physics English) The interactions caused by the strong force

strong interaction

n. (physics) the interaction that binds protons and neutrons together in the nuclei of atoms; mediated by gluons [syn: strong force, color force]

Strong interaction

In particle physics, the strong interaction is the mechanism responsible for the strong nuclear force (also called the strong force, nuclear strong force), one of the four known fundamental interactions, the others are electromagnetism, the weak interaction and gravitation. At the range of a femtometer, it is the strongest force, is approximately 137 times stronger than electromagnetism, a million times stronger than weak interaction and 10 times stronger than gravitation. The strong nuclear force ensures the stability of ordinary matter, confining quarks into hadron particles, such as the proton and neutron, and the further binding of neutrons and protons into atomic nuclei. Most of the mass-energy of a common proton or neutron is in the form of the strong force field energy; the individual quarks provide only about 1% of the mass-energy of a proton.

The strong interaction is observable at two ranges: on a larger scale (about 1 to 3 femtometers (fm)), it is the force that binds protons and neutrons (nucleons) together to form the nucleus of an atom. On the smaller scale (less than about 0.8 fm, the radius of a nucleon), it is the force (carried by gluons) that holds quarks together to form protons, neutrons, and other hadron particles. In the latter context, it is often known as the color force. The strong force inherently has such a high strength that hadrons bound by the strong force can produce new massive particles. Thus, if hadrons are struck by high-energy particles, they give rise to new hadrons instead of emitting freely moving radiation ( gluons). This property of the strong force is called color confinement, and it prevents the free "emission" of the strong force: instead, in practice, jets of massive particles are observed.

In the context of binding protons and neutrons together to form atomic nuclei, the strong interaction is called the nuclear force (or residual strong force). In this case, it is the residuum of the strong interaction between the quarks that make up the protons and neutrons. As such, the residual strong interaction obeys a quite different distance-dependent behavior between nucleons, from when it is acting to bind quarks within nucleons. The binding energy that is partly released on the breakup of a nucleus is related to the residual strong force and is harnessed in nuclear power and fission-type nuclear weapons.

The strong interaction is hypothesized to be mediated by massless particles called gluons, that are exchanged between quarks, antiquarks, and other gluons. Gluons, in turn, are thought to interact with quarks and gluons as all carry a type of charge called color charge. Color charge is analogous to electromagnetic charge, but it comes in three types rather than one (+/- red, +/- green, +/- blue) that results in a different type of force, with different rules of behavior. These rules are detailed in the theory of quantum chromodynamics (QCD), which is the theory of quark-gluon interactions.

After the Big Bang, during the electroweak epoch, the electroweak force separated from the strong force. A Grand Unified Theory is hypothesized to exist to describe this, no such theory has been successfully formulated yet, and the unification remains an unsolved problem in physics.

Usage examples of "strong interaction".

In the para-Universe, the strong interaction is a hundred times stronger than it is here, which means that nuclear fission is much more likely here than there, and nuclear fusion is much more likely there than here.

At some point the loss of force from the strong interaction of the local atomic nuclei would diminish their cohesion, and matter as this galaxy knew it would cease to exist.

Mary showed up, one year to the day after her first visit, for the formal ceremony in which an award was made, posthumously, to Heinrich Grunewald for his part in the development of the Grunewald-McAndrew formalism for the modified strong interaction.

That speeding H-sixty abruptly put three ships together within strong interaction range, since the other two were already at minimum safe separation.