172 research outputs found
Algebraic renormalization of N=2 Super Yang-Mills theories coupled to matter
We study the algebraic renormalization of Supersymmetric Yang--Mills
theories coupled to matter. A regularization procedure preserving both the BRS
invariance and the supersymmetry is not known yet, therefore it is necessary to
adopt the algebraic method of renormalization, which does not rely on any
regularization scheme. The whole analysis is reduced to the solution of
cohomology problems arising from the generalized Slavnov operator which
summarizes all the symmetries of the model. Besides to unphysical
renormalizations of the quantum fields, we find that the only coupling constant
of SYMs can get quantum corrections. Moreover we prove that all the
symmetries defining the theory are algebraically anomaly--free.Comment: typing error in eq. (A.9) correcte
Chiral Current Algebras in Three--Dimensional Bf--Theory with Boundary
We consider the three--dimensional BF--model with planar boundary in the
axial gauge. We find two--dimensional conserved chiral currents living on the
boundary and satisfying Kac--Moody algebras.Comment: 18 page
Massive gravity and Fierz-Pauli theory
Linearized gravity is considered as an ordinary gauge field theory. This
implies the need for gauge fixing in order to have well defined propagators.
Only after having achieved this, the most general mass term is added. The aim
of this paper is to study of the degrees of freedom of the gauge fixed theory
of linearized gravity with mass term. The main result is that, even outside the
usual Fierz-Pauli constraint on the mass term, it is possible to choose a gauge
fixing belonging to the Landau class, which leads to a massive theory of
gravity with the five degrees of freedom of a spin two massive particle.Comment: 12 pages, no figure
Massive deformations of rank-2 symmetric tensor theory (a.k.a. BRS characterization of Fierz-Pauli massive gravity)
In this paper we consider the issue of massive gravity from a pure field
theoretical point of view, as the massive deformation of the gauge theory for a
symmetric rank-2 tensor field. We look for the most general massive theory with
well defined propagators, imposing the absence of unphysical poles (ghosts). We
find several possibilities, depending on the choice of the gauge fixing term.
{Amongst these, two solutions with good massless limit are found.} The request
of the absence of ghosts, alone, does not isolate the Fierz-Pauli case: several
examples of massive theories, which may include or not the Fierz-Pauli mass
term, are given. On the other hand, the Fierz-Pauli theory can be uniquely
identified by means of a symmetry: it turns out the the Fierz-Pauli massive
gravity is the only element of the cohomology of a BRS operator.Comment: 18 pages, minor changes, refs adde
Infrared Regularization of Yang-Mills Theories
We introduce an infrared regulator in Yang--Mills theories under the form of
a mass term for the nonabelian fields. We show that the resulting action, built
in a covariant linear gauge, is multiplicatively renormalizable by proving the
validity at all orders of the Slavnov identity defining the theory.Comment: final version to appear in Mod.Phys.Lett.A. 8 pages + cover, plain
LaTe
Infrared and Ultraviolet Finiteness of Topological BF Theory in Two Dimensions
The two--dimensional topological BF model is considered in the Landau gauge
in the framework of perturbation theory. Due to the singular behaviour of the
ghost propagator at long distances, a mass term to the ghost fields is
introduced as infrared regulator. Relying on the supersymmetric algebraic
structure of the resulting massive theory, we study the infrared and
ultraviolet renormalizability of the model, with the outcome that it is
perturbatively finite.Comment: 26 pages, GEF-TH-11/199
Repairing Broken Algebras
We consider theories characterized by a set of Ward operators which do not
form a closed algebra. We impose the Slavnov--Taylor identity built out of the
Ward operators and we derive the acceptable breaking of the algebra and the
general form of the classical action. The 1PI generating functional is
expressed in terms of the known quantities characterizing the theory and of a
nontrivial integrability condition. As a nontrivial application of our
formalism, we discuss the N=4 supersymmetric nonlinear sigma model.Comment: one section containing a remarkable (and unexpected) result on N=4
supersymmetric sigma model has been added. 10 pages, plain LaTeX, no figure
Perturbation Theory for Antisymmetric Tensor Fields in Four Dimensions
Perturbation theory for a class of topological field theories containing
antisymmetric tensor fields is considered. These models are characterized by a
supersymmetric structure which allows to establish their perturbative
finiteness.Comment: 23 page
Algebraic Renormalization of Supersymmetric Yang-Mills Chern-Simons Theory in the Wess-Zumino Gauge
We consider a N=2 supersymmetric Yang-Mills-Chern-Simons model, coupled to
matter, in the Wess-Zumino gauge. The theory is characterized by a superalgebra
which displays two kinds of obstructions to the closure on the translations:
field dependent gauge transformations, which give rise to an infinite algebra,
and equations of motion. The aim is to put the formalism in a closed form,
off-shell, without introducing auxiliary fields. In order to perform that, we
collect all the symmetries of the model into a unique nilpotent Slavnov-Taylor
operator. Furthermore, we prove the renormalizability of the model through the
analysis of the cohomology arising from the generalized Slavnov-Taylor
operator. In particular, we show that the model is free of anomaly.Comment: 17 pages, latex, no figures. Computation of the cohomology corrected.
Appendix adde
Non-Renormalization Properties of the Chern-Simons Action Coupled to Matter
We analyze an abelian gauge model in 3 dimensions which includes massless
scalar matter fields. By controlling the trace anomalies with a local
dilatation Ward identity, we show that, in perturbation theory and within the
BPHZL scheme, the Chern-Simons term has no radiative corrections. This implies,
in particular, the vanishing of the corresponding function in the
renormalization group equation.Comment: 11 page
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