title: Color Confinement and Screening in the θ Vacuum of QCD.
abstract: QCD perturbation theory ignores the compact nature of the SU(3) gauge group that gives rise to the periodic θ vacuum of the theory. We propose to modify the gluon propagator to reconcile perturbation theory with the anomalous Ward identities for the topological current in the θ vacuum. As a result, the gluon couples to the Veneziano ghost describing the tunneling transitions between different Chern-Simons sectors of the vacuum; we call the emerging gluon dressed by ghost loops a "glost." We evaluate the glost propagator and find that it has the form G(p)=(p(2)+χ(top)/p(2))(-1) where χ(top) is the Yang-Mills topological susceptibility related to the η' mass by the Witten-Veneziano relation; this propagator describes the confinement of gluons at distances ∼χ(top)(-1/4)≃1  fm. The same functional form of the propagator was originally proposed by Gribov as a solution to the gauge copies problem that plagues perturbation theory. The resulting running coupling coincides with the perturbative one at p(2)≫√[χ(top)], but in the infrared region either freezes (in pure Yang-Mills theory) or vanishes (in full QCD with light quarks), in accord with experimental evidence. Our scenario makes explicit the connection between confinement and topology of the QCD vacuum; we discuss the implications for spin physics, high energy scattering, and the physics of quark-gluon plasma.
authors.affiliation: Department of Physics and Astronomy, Stony Brook University, New York 11794-3800, USA.|Department of Physics and RIKEN-BNL Research Center, Brookhaven National Laboratory, Upton, New York 11973-5000, USA.
authors.forename: Dmitri E
authors.initials: DE
authors.lastname: Kharzeev
authors.affiliation: Department of Particle Physics, School of Physics and Astronomy, Tel Aviv University, Tel Aviv 69978, Israel.|Departamento de Física, Universidad Técnica Federico Santa María and Centro Científico-Tecnológico de Valparaíso, Casilla 110-V, Valparaiso, Chile.
authors.forename: Eugene M
authors.initials: EM
authors.lastname: Levin