Asymptotic freedom

Since limL oo E.r(L, P) = 0, we find that y(oo, oo, A) = A is the renormalized fixed coupling constant in free space at zero temperature. On the other hand, for either L — 0 or P —> 0, T,r(L,P) diverges implying that we have ultraviolet asymptotic freedom for short distances and/or for high temperatures, irrespective of the value of A. 

At high density, quarks in dense matter interact weakly with each other and form a Fermi sea, due to asymptotic freedom. When the energy is much less... 

S. C. Frautschi, Asymptotic freedom and color superconductivity in dense quark matter, in Proceedings of the Workshop on Hadronic Matter at Extreme Energy Density, N. Cabibbo, Editor, Erice, Italy (1978). 

Asymptotic freedom explains the successes of the parton model of pointlike objects inside hadrons and enables systematic corrections to the parton model to be calculated using perturbation theory. That the in-... 

QCD has the important property of asymptotic freedom - that at very high energies (and, hence, short distances) the interactions between quarks tend to zero as the distance between them tends to zero. Because of asymptotic freedom, perturbation theory maybe used to calculate the high energy aspects of strong interactions, such as those described by the parton modeL... 

For the discovery of asymptotic freedom in the theory of the strong interaction 1973-1974 D. J. Gross 2004 (physics)... 

Due to the asymptotic freedom in QCD, the interaction between quarks and gluons becomes arbitrarily weak at short distances. Consequently hadrons behave as collections of free partons at large transferred momenta and their interaction can therefore be described using a parton model. 

H.D. Politzer, Asymptotic freedom an approach to strong interactions. Phys. Rept. 14,129-180... 

G. AltareUi, G. Parisi, Asymptotic freedom in parton panguage. Nucl. Phys. B 126,298 (1977)... 

The procedure for obtaining the QED potential cannot be directly taken over into QCD to calculate the properties of quarkonium. The reason is that in contrast to QED, QCD is a non-Abelian field theory. Because of this, the running coupling of QCD is weak at very small distances between quarks (asymptotic freedom), but becomes strong at large interquark separations. Therefore, we can use lowest-order QCD perturbation theory to describe the quark-antiquark potential only at very small distances. 

Many authors have computed corrections to the static QCD perturbative potential (Coulomb potential). The simplest correction is to let the coupling run in accordance with asymptotic freedom. Also, one-loop terms have been computed, for example, by Pantaleone et al (1986). But, so far, even the Coulomb nature of the short-distance potential has not been established firom quarkonium data, much less the nature of the higher-order corrections. 

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