Nonperturbative ghost dynamics in the maximal Abelian gauge

We construct the effective potential for the ghost condensate in the maximal Abelian gauge. This condensate is an order parameter for a global continuous symmetry, which is spontaneously broken since a nonvanishing value of lowers the vacuum energy. The associated Goldstone mode turns out to be unphysical.Comment: 16 pages. v2: version accepted for publication in JHE

Dimension two gluon condensates in a variety of gauges and a gauge invariant Yang-Mills action with a mass

We give a short overview of our work concerning the dimension two operator A^2 in the Landau gauge and its generalizations to other gauges. We conclude by discussing recent work that leads to a renormalizable gauge invariant action containing a mass parameter, based on the operator F 1/D^2 F.Comment: 4 pages. espcrc2.sty is used. Talk given at "13th International Conference In QCD (QCD 06), 3-7 Jul 2006, Montpellier, France

Renormalization properties of the mass operator A^2 in three dimensional Yang-Mills theories in the Landau gauge

Massive renormalizable Yang-Mills theories in three dimensions are analysed within the algebraic renormalization in the Landau gauge. In analogy with the four dimensional case, the renormalization of the mass operator A^2 turns out to be expressed in terms of the fields and coupling constant renormalization factors. We verify the relation we obtain for the operator anomalous dimension by explicit calculations in the large N_f. The generalization to other gauges such as the nonlinear Curci-Ferrari gauge is briefly outlined.Comment: 15 pages, 3 figure

Ghost Condensates and Dynamical Breaking of SL(2,R) in Yang-Mills in the Maximal Abelian Gauge

Ghost condensates of dimension two in SU(N) Yang-Mills theory quantized in the Maximal Abelian Gauge are discussed. These condensates turn out to be related to the dynamical breaking of the SL(2,R) symmetry present in this gaugeComment: 16 pages, LaTeX2e, final version to appear in J. Phys.

From propagators to glueballs in the Gribov-Zwanziger framework

Over the last years, lattice calculations in pure Yang-Mills gauge theory seem to have come more or less to a consensus. The ghost propagator is not enhanced and the gluon propagator is positivity violating, infrared suppressed and non-vanishing at zero momentum. From an analytical point of view, several groups are agreeing with these results. Among them, the refined Gribov-Zwanziger (RGZ) framework also accommodates for these results. The question which rises next is, if our models hold the right form for the propagators, how to extract information on the real physical observables, i.e. the glueballs? How do the operators which represent glueballs look like? We review the current status of this matter within the RGZ framework.Comment: 3 pages, Conference contribution for Confinement IX, Madrid 2010 (30/08-03/09), to appear in American Institute of Physics (AIP

A study of the zero modes of the Faddeev-Popov operator in Euclidean Yang-Mills theories in the Landau gauge in d=2,3,4 dimensions

Examples of normalizable zero modes of the Faddeev-Popov operator in SU(2) Euclidean Yang-Mills theories in the Landau gauge are constructed in d=2,3,4 dimensions.Comment: 18 pages. Text modifications. References added. Version accepted for publication in the EPJ

Renormalizability of the local composite operator A^2 in linear covariant gauges

The local composite operator $A_{\mu}^{2}$ is analysed within the algebraic renormalization in Yang-Mills theories in linear covariant gauges. We establish that it is multiplicatively renormalizable to all orders of perturbation theory. Its anomalous dimension is computed to two-loops in the MSbar scheme.Comment: 10 pages, LaTeX, final version to appear in Phys. Lett.

(Lattice) Propagators and Extraction of Spectral Densities

In this proceeding, we explain a few steps for an alternative extraction of the spectral density of a two-point function (propagator) based on a discrete set of data points. We present a so-called Tikhonov regularization of this particular inverse problem. We test it on 2 cases: lattice 0++} glueball data and mock gluon data.Comment: 8 pages, 4 figures. Proceedings of Xth Quark Confinement and the Hadron Spectrum, October 8-12, 2012, TUM Campus Garching, Munich, German