The (Lattice) QCD potential and coupling: How to accurately interpolate between multiloop QCD and the string picture
Aug, 199447 pages
Published in:
- Phys.Rev.D 51 (1995) 5130-5152
e-Print:
- hep-lat/9408016 [hep-lat]
Report number:
- CLNS-94-1294-REV,
- CLNS-94-1294
Citations per year
Abstract: (APS)
We present a simple parametrization of the running coupling constant αV(q), defined via the static potential, that interpolates between two-loop QCD in the UV and the string prediction V(r)=σr-π/12r in the IR. In addition to the usual Λ parameter and the string tension σ, αV(q) depends on one dimensionless parameter, determining how fast the crossover from UV to IR behavior occurs (in principle we know how to take into account any number of loops by adding more parameters). Using a new Ansatz for the lattice potential in terms of the continuum αV(q), we can fit quenched and unquenched Monte Carlo results for the potential down to one lattice spacing, and at the same time extract αV(q) to high precision. We compare our Ansatz with one-loop results for the lattice potential, and use αV(q) from our fits to quantitatively check the accuracy of two-loop evolution, compare with the Lepage-Mackenzie estimate of the coupling extracted from the plaquette, and determine Sommer’s scale r0 much more accurately than previously possible. For pure SU(3) we find that αV(q) scales on the percent level for β≥6.Note:
- Revised Version •
- 47 pages, incl. 4 figures in LaTeX [Added remarks on correlated vs. uncorrelated fits in sect. 4; corrected misprints; updated references.]
- quantum chromodynamics
- lattice field theory
- quark: potential
- coupling constant: parametrization
- parametrization: coupling constant
- string model
- Wilson loop
- infrared problem
- renormalization
- perturbation theory: higher-order
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