FACTOID # 14: North Carolina has a larger Native American population than North Dakota, South Dakota and Montana combined.
 
 Home   Encyclopedia   Statistics   States A-Z   Flags   Maps   FAQ   About 
 
WHAT'S NEW
 

SEARCH ALL

FACTS & STATISTICS    Advanced view

Search encyclopedia, statistics and forums:

 

 

(* = Graphable)

 

 


Encyclopedia > Strong interaction

The strong interaction or strong force is today understood to represent the interactions between quarks and gluons as detailed by the theory of quantum chromodynamics (QCD). The strong force is the fundamental force mediated by gluons, acting upon quarks, antiquarks, and the gluons themselves. Of the four fundamental forces, the strong interaction is the most powerful. For other uses, see Interaction (disambiguation). ... For other uses, see Quark (disambiguation). ... In particle physics, gluons are subatomic particles that cause quarks to interact, and are indirectly responsible for the binding of protons and neutrons together in atomic nuclei. ... Quantum chromodynamics (abbreviated as QCD) is the theory of the strong interaction (color force), a fundamental force describing the interactions of the quarks and gluons found in hadrons (such as the proton, neutron or pion). ... A fundamental interaction is a mechanism by which particles interact with each other, and which cannot be explained by another more fundamental interaction. ... In physics, gluons are the bosonic particles which are responsible for the strong nuclear force. ... For other uses, see Quark (disambiguation). ... Corresponding to most kinds of particle, there is an associated antiparticle with the same mass and opposite charges. ... In particle physics, gluons are subatomic particles that cause quarks to interact, and are indirectly responsible for the binding of protons and neutrons together in atomic nuclei. ...


The strong force only acts directly upon elementary particles. However, a residual of the force is observed between hadrons (the best known example being the force that acts between nucleons in atomic nuclei) as the nuclear force. Here the strong force acts indirectly, transmitted as gluons which form part of the virtual pi and rho mesons which classically transmit the nuclear force (see this topic for more). As has been shown by many failed free quark searches, the elementary particles affected are unobservable directly. This phenomenon is called confinement, a theory which allows only hadrons to be seen. A hadron, in particle physics, is a subatomic particle which experiences the nuclear force. ... In physics a nucleon is a collective name for two baryons: the neutron and the proton. ... A Feynman diagram of a strong proton-neutron interaction mediated by a neutral pion. ... In particle physics, a meson is a strongly interacting boson, that is, it is a hadron with integral spin. ... A free quark is a quark that is not bound to another quark (or, in general, not part of a color-neutral) group. ... Colour confinement (often just confinement) is the physics phenomenon that color charged particles (such as quarks) cannot be isolated. ...


History

Before the 1970s, when protons and neutrons were thought to be fundamental particles, the phrase "strong force" referred to what is today known as the nuclear force or the residual strong force. What were being observed were the "residual" effects of the strong force, which act on hadrons, both baryons and mesons. This force was postulated to overcome the electric repulsion between protons in the nucleus, and for its strength (at short distances) it was dubbed the "strong force". After the discovery of quarks, scientists realized that the force was actually acting upon the quarks and gluons making up the protons, not the protons themselves. For some time after this realization, the older notion was referred to as the residual strong force, and the "new" strong interaction was called color force. The 1970s decade refers to the years from 1970 to 1979, also called The Seventies. ... For other uses, see Proton (disambiguation). ... This article or section does not adequately cite its references or sources. ... In particle physics, an elementary particle is a particle of which other, larger particles are composed. ... A Feynman diagram of a strong proton-neutron interaction mediated by a neutral pion. ... Combinations of three u, d or s-quarks with a total spin of 3/2 form the so-called baryon decuplet. ... Mesons of spin 1 form a nonet In particle physics, a meson is a strongly interacting boson, that is, it is a hadron with integral spin. ... Electromagnetism is the physics of the electromagnetic field: a field which exerts a force on particles that possess the property of electric charge, and is in turn affected by the presence and motion of those particles. ... The nucleus of an atom is the very small dense region, of positive charge, in its centre consisting of nucleons (protons and neutrons). ...


Details

Quantum chromodynamics, a part of the standard model of particle physics, is a typical non-Abelian gauge theory based on a local (gauge) symmetry group called SU(3). All the particles in this theory interact with each other, through the strong force. The strength of the interaction is parametrized by the strong coupling constant. This strength is, as usual, modified by the gauge colour charge of the particle. This really refers to a group theoretical property whose meaning is explained in the article on colour charge and has nothing to do with colour as such. Quarks and gluons are the only fundamental particles which carry non-vanishing colour charge, and hence participate in the strong interactions. Quantum chromodynamics (abbreviated as QCD) is the theory of the strong interaction (color force), a fundamental force describing the interactions of the quarks and gluons found in hadrons (such as the proton, neutron or pion). ... The Standard Model of Fundamental Particles and Interactions For the Standard Model in Cryptography, see Standard Model (cryptography). ... In mathematics, an abelian group, also called a commutative group, is a group (G, *) such that a * b = b * a for all a and b in G. Abelian groups are named after Niels Henrik Abel. ... In physics, gauge theories are a class of physical theories based on the idea that symmetry transformations can be performed locally as well as globally. ... The symmetry group of an object (e. ... In mathematics, the special unitary group of degree n is the group of n by n unitary matrices with determinant 1 and entries from the field C of complex numbers, with the group operation that of matrix multiplication. ... In physics, a coupling constant, usually denoted g, is a number that determines the strength of an interaction. ... In physics, a coupling constant, usually denoted g, is a number that determines the strength of an interaction. ... Group theory is that branch of mathematics concerned with the study of groups. ... In quantum chromodynamics (QCD), color or color charge refers to a certain property of the subatomic particles called quarks. ... Color is an important part of the visual arts. ...


See also

The weak interaction (often called the weak force or sometimes the weak nuclear force) is one of the four fundamental interactions of nature. ... Electromagnetism is the physics of the electromagnetic field: a field which exerts a force on particles that possess the property of electric charge, and is in turn affected by the presence and motion of those particles. ... Gravity is a force of attraction that acts between bodies that have mass. ... The Standard Model of Fundamental Particles and Interactions For the Standard Model in Cryptography, see Standard Model (cryptography). ... Thousands of particles explode from the collision point of two relativistic (100 GeV per nucleon) gold ions in the STAR detector of the Relativistic Heavy Ion Collider. ... This is a detailed description of the standard model (SM) of particle physics. ... Quantum field theory (QFT) is the quantum theory of fields. ... In physics, gauge theories are a class of physical theories based on the idea that symmetry transformations can be performed locally as well as globally. ... Quantum chromodynamics (abbreviated as QCD) is the theory of the strong interaction (color force), a fundamental force describing the interactions of the quarks and gluons found in hadrons (such as the proton, neutron or pion). ... Quark matter or QCD matter refers to any of a number of phases of matter whose degrees of freedom include quarks and gluons. ... The nuclear force (or inter-nucleon potential) is the force between two or more nucleons. ... Nuclear physics is the branch of physics concerned with the nucleus of the atom. ... In physics, a coupling constant, usually denoted g, is a number that determines the strength of an interaction. ... Binding energy is the energy required to disassemble a whole into separate parts. ... A Feynman diagram of a strong proton-neutron interaction mediated by a neutral pion. ...

References

  • David J. Griffiths, 1987. Introduction to Elementary Particles. John Wiley & Sons. ISBN 0-471-60386-4
  • Gordon L. Kane (1987). Modern Elementary Particle Physics. Perseus Books. ISBN 0-201-11749-5. 
  • Richard Morris, 2003. The Last Sorcerers: The Path from Alchemy to the Periodic Table. Washington DC: Joseph Henry Press. ISBN 0-309-50593-3

David J. Griffiths is a U.S. physicist and educator. ...

External links


 
 

COMMENTARY     


Share your thoughts, questions and commentary here
Your name
Your comments

Want to know more?
Search encyclopedia, statistics and forums:

 


Press Releases |  Feeds | Contact
The Wikipedia article included on this page is licensed under the GFDL.
Images may be subject to relevant owners' copyright.
All other elements are (c) copyright NationMaster.com 2003-5. All Rights Reserved.
Usage implies agreement with terms, 1022, m