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Register a new userCasimir energy in the Gribov-Zwanziger approach to QCD
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In this paper we study the Casimir energy of QCD within the Gribov-Zwanziger approach. In this model non-perturbative effects of gauge copies are properly taken into account. We show that the computation of the Casimir energy for the MIT bag model within the (refined) Gribov-Zwanziger approach not only gives the correct sign but it also gives an estimate for the radius of the bag.
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The Refined Gribov-Zwanziger framework takes into account the existence of equivalent gauge field configurations in the gauge-fixing quantization procedure of Euclidean Yang-Mills theories. Recently, this setup was extended to the family of linear covariant gauges giving rise to a local and BRST-invariant action. In this paper, we give an algebraic proof of the renormalizability of the resulting action to all orders in perturbation theory.
The 3-point vertices of QCD are examined at the symmetric subtraction point at one loop in the Landau gauge in the presence of the Gribov mass, gamma. They are expanded in powers of gamma^2 up to dimension four in order to determine the order of the leading correction. As well as analysing the pure Gribov-Zwanziger Lagrangian, its extensions to include localizing ghost masses are also examined. For comparison a pure gluon mass term is also considered.
In this paper, we discuss the gluon propagator in the linear covariant gauges in $D=2,3,4$ Euclidean dimensions. Non-perturbative effects are taken into account via the so-called Refined Gribov-Zwanziger framework. We point out that, as in the Landau and maximal Abelian gauges, for $D=3,4$, the gluon propagator displays a massive (decoupling) behaviour, while for $D=2$, a scaling one emerges. All results are discussed in a setup that respects the Becchi-Rouet-Stora-Tyutin (BRST) symmetry, through a recently introduced non-perturbative BRST transformation. We also propose a minimizing functional that could be used to construct a lattice version of our non-perturbative definition of the linear covariant gauge.
In this paper we solved the new evolution equation for high energy scattering amplitudethat stems from the Gribov-Zwanziger approach to the confinement of quarks and gluons. We found that (1) the energy dependence of the scattering amplitude turns out to be the same as for QCD BFKL evolution; (2) the spectrum of the new equation does not depend on the details of the Gribov-Zwanzinger approach and (3) all eigenfunctions coincide with the eigenfunctions of the QCD BFKL equation at large transverse momenta $kappa,geq,1$. The numerical calculations show that there exist no new eigenvalues with the eigenfunctions which decrease faster than solutions of the QCD BFKL equation at large transverse momenta. The structure of the gluon propagator in Gribov-Zwanziger approach, that stems from the lattice QCD and from the theoretical evaluation, results in the exponential suppression of the eigenfunctions at long distances and in the resolution of the difficulties, which the Colour Glass Condensate (CGC) and some other approaches, based on perturbative QCD, face at large impact parameters. We can conclude that the confinement of quark and gluons, at least in the form of Gribov-Zwanziger approach, does not influence on the scattering amplitude except solving the long standing theoretical problem of its behaviour at large impact parameters.
An approach to realize a hyperon as a bound-state of a two-flavor baryon and a kaon is considered in the context of the Sakai-Sugimoto model of holographic QCD, which approach has been known in the Skyrme model as the bound-state approach to strangeness. As a simple case of study, pseudo-scalar kaon is considered as fluctuation around a baryon. In this case, strongly-bound hyperon-states are absent, different from the case of the Skyrme model. Observed is a weak bound-state which would correspond to Lambda(1405).
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