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In physics, asymptotic freedom is the property of some gauge theories in which the interaction between the particles, such as quarks, becomes arbitrarily weak at ever shorter distances, i.e. length scales that asymptotically converge to zero (or, equivalently, energy scales that become arbitrarily large).1 Discovery
The fact that asymptotic freedom is a feature of quantum chromodynamics (QCD), the quantum field theory of the interactions of quarks and gluons, was discovered by David Gross, Frank Wilczek, and David Politzer in 1973. For their discovery, Gross, Wilczek and Politzer were awarded the Nobel Prize in Physics in 2004.
Asymptotic freedom implies that in high-energy scattering the quarks move within nucleonNucleon is the common name used in nuclear chemistry to refer to a neutron or a proton, the components of an atom's nucleus. The total number of nucleons in an atom is the mass number on the atom, as nucleons each have a mass of one amu. See also List ofs, such as the neutronNeutron Classification Subatomic particle Fermion Hadron Baryon Nucleon Neutron Properties Mass: 940 MeV/ c 2 Electric Charge: 0 C Spin: 1/2 In physics, the neutron is a subatomic particle with no net electric charge and a mass of 940 MeV/ c 2 ( kg; very and protonFor alternative meanings see proton (disambiguation). Proton Classification Subatomic particle Fermion Hadron Baryon Nucleon Proton Properties Mass: 938 MeV/ c2 Electric Charge: 1. 6 × 10−19 C Spin: 1/2 In physics, the proton is a subatomic particle, essentially as free, non-interacting particles, and it allows physicists to calculate the cross sectionsSoda can stove with a Cross section in yellow. In geometry, a cross section is the intersection of a body in 3-dimensional space with a plane, or of a body in 2-dimensional space with a line, etc. More plainly, when cutting an object into slices one gets of various events in particle physicsParticle physics is a branch of physics that studies the elementary constituents of matter and radiation, and the interactions between them. It is also called high energy physics because many elementary particles do not occur under normal circumstances in reliably using partonIn particle physics, the parton was an hypothetical fundamental particle considered, in the 'parton model' of strong interactions, to be a constituent of the hadron. In the 1970s, quantum chromodynamics showed that hadrons are composed of quarks, but the techniques.
The discovery also helped rehabilitate the reputation of quantum field theory (QFT) as a coherent description of particle interactions. Prior to 1973, many theorists suspected that QFT was rendered fundamentally incoherent by the short-distance Landau poleIn physics, Landau pole is the energy scale (or the precise value of the energy) where a coupling constant (the strength of an interaction) of a quantum field theory becomes infinite. Such a possibility was pointed out by the eminent Russian physicist Lev that arose in quantum electrodynamicsQuantum electrodynamics QED is a quantum field theory of electromagnetism. QED describes all phenomena involving electrically charged particles interacting by means of the electromagnetic force and has been called "the jewel of physics" for its extremely and some other field theories. Asymptotically free theories, however, lack this Landau pole. The discovery of asymptotic freedom was therefore a key development toward the emergence of a Standard Model of particle physics based on quantum field theory.
(While the Standard Model is not itself entirely asymptotically free, the phenomenon raises the possibility that it could be an effective field theory approximation to an asymptotically free grand unified theory; and since its strong interactions are asymptotically free, any Landau poles in it are banished anyway to a realm far beneath the Planck length.)
