1,951 research outputs found
The universal character of Zwanziger's horizon function in Euclidean Yang-Mills theories
In light of the recently established BRST invariant formulation of the
Gribov-Zwanziger theory, we show that Zwanziger's horizon function displays a
universal character. More precisely, the correlation functions of local BRST
invariant operators evaluated with the Yang-Mills action supplemented with a
BRST invariant version of the Zwanziger's horizon function and quantized in an
arbitrary class of covariant, color invariant and renormalizable gauges which
reduce to the Landau gauge when all gauge parameters are set to zero, have a
unique, gauge parameters independent result, corresponding to that of the
Landau gauge when the restriction to the Gribov region in the latter
gauge is imposed. As such, thanks to the BRST invariance, the cut-off at the
Gribov region acquires a gauge independent meaning in the class of the
physical correlators.Comment: 14 pages. v2: version accepted by Phys.Lett.
Cenomanian Ammonites from the Sierra de Tlahualilo, Coahuila, Mexico
267-287http://deepblue.lib.umich.edu/bitstream/2027.42/48310/2/ID150.pd
Some remarks on the spectral functions of the Abelian Higgs Model
We consider the unitary Abelian Higgs model and investigate its spectral
functions at one-loop order. This analysis allows to disentangle what is
physical and what is not at the level of the elementary particle propagators,
in conjunction with the Nielsen identities. We highlight the role of the
tadpole graphs and the gauge choices to get sensible results. We also introduce
an Abelian Curci-Ferrari action coupled to a scalar field to model a massive
photon which, like the non-Abelian Curci-Ferarri model, is left invariant by a
modified non-nilpotent BRST symmetry. We clearly illustrate its non-unitary
nature directly from the spectral function viewpoint. This provides a
functional analogue of the Ojima observation in the canonical formalism: there
are ghost states with nonzero norm in the BRST-invariant states of the
Curci-Ferrari model.Comment: 32 pages, 12 figure
More on the non-perturbative Gribov-Zwanziger quantization of linear covariant gauges
In this paper, we discuss the gluon propagator in the linear covariant gauges
in 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 , the gluon
propagator displays a massive (decoupling) behaviour, while for , 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.Comment: 15 pages, 1 figure; V2 typos fixed and inclusion of section on the
ghost propagator. To appear in PhysRev
An exact nilpotent non-perturbative BRST symmetry for the Gribov-Zwanziger action in the linear covariant gauge
We point out the existence of a non-perturbative exact nilpotent BRST
symmetry for the Gribov-Zwanziger action in the Landau gauge. We then put
forward a manifestly BRST invariant resolution of the Gribov gauge fixing
ambiguity in the linear covariant gauge.Comment: 8 pages. v2: version accepted for publication in PhysRev
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