Where is the string limit in QCD?
Abstract
The energies of glue in the presence of a static quark-antiquark pair are calculated for separations r ranging from 0.1 fm to 4 fm and for various quark-antiquark orientations on the lattice. Our simulations use an improved gauge-field action on anisotropic space-time lattices. Discretization errors and finite volume effects are studied. We find that the spectrum does not exhibit the expected onset of the universal pi/r Goldstone excitations of the effective QCD string, even for r as large as 4 fm. Our results cast serious doubts on the validity of treating glue in terms of a fluctuating string for r below 2 fm. Retardation effects in the Upsilon system are also studied by comparing level splittings from the Born-Oppenheimer approximation with those directly obtained in simulations.
Keywords
Cite
@article{arxiv.hep-lat/9809098,
title = {Where is the string limit in QCD?},
author = {K. J. Juge and J. Kuti and C. J. Morningstar},
journal= {arXiv preprint arXiv:hep-lat/9809098},
year = {2009}
}
Comments
LATTICE98(confine), 6 pages, LaTeX (3 figures), uses espcrc2.sty. Talk and poster given at the XVI International Symposium on Lattice Field Theory, Boulder, CO, USA, 13-18 July 1998