On QCD strings beyond non-interacting model

Abstract

We investigate the implications of Nambu-Goto (NG), Lscher-Weisz (LW) and Polyakov-Kleinert (PK) string actions for the Casimir energy of the QCD flux-tube at one and two loop order at finite temperature. We perform our numerical study on the 4-dim pure SU(3) Yang-Mills lattice gauge theory at finite temperature and coupling β = 6.0. The static quark-antiquark potential is calculated using link-integrated Polyakov loop correlators. At a high temperature-close to the critical point-We find that the rigidity and self-interactions effects of the QCD string to become detectable. The remarkable feature of this model is that it retrieves a correct dependency of the renormalized string tension on the temperature. Good fit to static potential data at source separations R ≥ 0.5 fm is obtained when including additional two-boundary terms of (LW) action. On the other-hand, at a lower temperature-near the QCD plateau-We detect signatures of two boundary terms of the Lscher-Weisz (LW) string action. The (LW) string with boundary action is yielding a static potential which is in a good agreement with the lattice Monte-Carlo data, however, for color source separation as short as R = 0.3 fm.