Nonperturbative Physics at Short Distances
نویسنده
چکیده
There is accumulating evidence in lattice QCD that attempts to locate confining fields in vacuum configurations bring results explicitly depending on the lattice spacing (that is, ultraviolet cut off). Generically, one deals with lowdimensional vacuum defects which occupy a vanishing fraction of the total four-dimensional space. We review briefly existing data on the vacuum defects and their significance for confinement and other non-perturbative phenomena. We introduce the notion of ‘quantum numbers’ of the defects and draw an analogy, rather formal one, to developments which took place about 50 years ago and were triggered by creation of the Sakata model.
منابع مشابه
Nonperturbative Effects in Quarkonia Associated with Large Orders in Perturbation Theory
We show that the perturbation series for quarkonia energies diverges at large orders. This results in a perturbative ambiguity in the energy that scales as e−1/aΛ where a is the Bohr radius of quarkonium and Λ is the QCD scale parameter. This ambiguity is associated with a nonperturbative contribution to the energy from distances of order Λ−1 and greater. This contribution is separate from that...
متن کاملHard Scattering in Qcd
Recent developments in the theory and experiment of QCD hard scattering are described. 1 Preamble: How Perturbative QCD Works This has been an active year for experimental results and theoretical developments in quantum chromodynamics. In this talk I will cover a selection of topics presented at this conference, tied together by the interplay of soft and hard physics. QCD is certainly the most ...
متن کاملPerturbative-nonperturbative interference in the static QCD interaction at small distances
Short distance static quark–antiquark interaction is studied systematically using the background perturbation theory with nonperturbative background described by field correlators. A universal linear term 3Ncαsσr 2π is observed at small distance r due to the interference between perturbative and nonperturbative contributions. Possible modifications of this term due to additional subleading term...
متن کاملar X iv : h ep - p h / 96 10 33 6 v 1 1 1 O ct 1 99 6 Nonperturbative Flow Equations and Low – Energy QCD ∗
We review the formalism of the effective average action in quantum field theory which corresponds to a coarse grained free energy in statistical mechanics. The associated exact renormalization group equation and possible nonperturbative approximations for its solution are discussed. This is applied to QCD where one observes the consecutive emergence of mesonic bound states and spontaneous chira...
متن کاملA Weak-Coupling Treatment of Nonperturbative QCD Dynamics to Heavy Hadrons
Based on the recently developed light-front similarity renormalization group approach and the light-front heavy quark effective theory, we derive analytically from QCD a heavy quark light-front Hamiltonian which contains explicitly a confinement interaction at long distances and a Coulomb-type interaction at short distances. With this light-front QCD Hamiltonian, we further demonstrate that the...
متن کاملHard scattering factorization and light cone hamiltonian approach to diffractive processes
We describe diffractive deeply inelastic scattering in terms of diffractive parton distributions. We investigate these distributions in a hamiltonian formulation that emphasizes the spacetime picture of diffraction scattering. For hadronic systems with small transverse size, diffraction occurs predominantly at short distances and the diffractive parton distributions can be studied by perturbati...
متن کامل