Article

# Unitarity analysis of a non-Abelian gauge invariant action with a mass

Phys. Rev. D 07/2007; 76(2). DOI:10.1103/PhysRevD.76.025006
Source: arXiv

ABSTRACT In previous work done by us and coworkers, we have been able to construct a local, non-Abelian gauge invariant action with a mass parameter, based on the nonlocal gauge invariant mass dimension two operator Fμν(D2)-1Fμν. The renormalizability of the resulting action was proven to all orders of perturbation theory, in the class of linear covariant gauges. We also discussed the perturbative equivalence of the model with ordinary massless Yang-Mills gauge theories when the mass is identically zero. Furthermore, we pointed out the existence of a Becchi-Rouet-Stora-Tyutin (BRST) symmetry with corresponding nilpotent charge. In this paper, we study the issue of unitarity of this massive gauge model. First, we provide a short review how to discuss the unitarity making use of the BRST charge. Afterwards we make a detailed study of the most general version of our action, and we come to the conclusion that the model is not unitary, as we are unable to remove all the negative norm states from the physical spectrum in a consistent way.

0 0
·
0 Bookmarks
·
27 Views
• ##### Article: Emerging phenomenology of 〈 A min 2〉
[hide abstract]
ABSTRACT: We consider phenomenology of the vacuum condensate 〈Amin2〉 in SU(2) gauge theory, where A is the gauge potential. Both physical manifestations and measurements of the condensate are discussed. A two-component picture for the condensate is presented according to which finite values of order Λ2QCD are associated both with large and short distances. We obtain a lower bound on the 〈Amin2〉 by considering its change across the phase transition.
Physics Letters B - PHYS LETT B. 01/2001; 501(1):28-36.
• Source
##### Article: Gluon propagator and quark confinement
[hide abstract]
ABSTRACT: The gluon propagator is investigated in Landau and in maximal center gauge for the gauge group SU(2) by means of lattice gauge simulations. We find that Gribov ambiguities arising from the implementation of Landau gauge have a small influence on the propagator. In agreement with previous findings, we obtain that the small momentum behavior is dominated by a mass, which is of order , where σ is the string tension. By removing the confining vortices from the full Yang–Mills ensemble, we convert full YM-theory into a theory which does not confine quarks. We find that in the latter case the strength of the gluon propagator in the intermediate momentum range is strongly reduced. The spectral functions which reproduce the numerical data for the propagators are analyzed using a generalized Maximum Entropy Method.
Nuclear Physics B. 01/2002;
• Source
##### Article: An analytic study of the off-diagonal mass generation for Yang-Mills theories in the maximal Abelian gauge
[hide abstract]
ABSTRACT: We investigate a dynamical mass generation mechanism for the off-diagonal gluons and ghosts in SU(N) Yang-Mills theories, quantized in the maximal Abelian gauge. Such a mass can be seen as evidence for the Abelian dominance in that gauge. It originates from the condensation of a mixed gluon-ghost operator of mass dimension two, which lowers the vacuum energy. We construct an effective potential for this operator by a combined use of the local composite operators technique with the algebraic renormalization and we discuss the gauge parameter independence of the results. We also show that it is possible to connect the vacuum energy, due to the mass dimension two condensate discussed here, with the non-trivial vacuum energy originating from the condensate <A^2>, which has attracted much attention in the Landau gauge. Comment: 24 pages, 2 .eps figures. v2: version accepted for publication in Phys.Rev.D
Physical Review D 12/2004; 70:114038. · 4.69 Impact Factor