1,031 research outputs found
Algebraic Properties of BRST Coupled Doublets
We characterize the dependence on doublets of the cohomology of an arbitrary
nilpotent differential s (including BRST differentials and classical linearized
Slavnov-Taylor (ST) operators) in terms of the cohomology of the
doublets-independent component of s. All cohomologies are computed in the space
of local integrated formal power series. We drop the usual assumption that the
counting operator for the doublets commutes with s (decoupled doublets) and
discuss the general case where the counting operator does not commute with s
(coupled doublets). The results are purely algebraic and do not rely on
power-counting arguments.Comment: Some explanations enlarged, references adde
Symmetry aspects of fermions coupled to torsion and electromagnetic fields
We study and explore the symmetry properties of fermions coupled to dynamical
torsion and electromagnetic fields. The stability of the theory upon radiative
corrections as well as the presence of anomalies are investigated.Comment: 9 pages, LaTe
Space-time dependent couplings in N=1 SUSY gauge theories: Anomalies and Central Functions
We consider N=1 supersymmetric gauge theories in which the couplings are
allowed to be space-time dependent functions. Both the gauge and the
superpotential couplings become chiral superfields. As has recently been shown,
a new topological anomaly appears in models with space-time dependent gauge
coupling. Here we show how this anomaly may be used to derive the NSVZ beta
function in a particular, well-determined renormalisation scheme, both without
and with chiral matter. Moreover we extend the topological anomaly analysis to
theories coupled to a classical curved superspace background, and use it to
derive an all-order expression for the central charge c, the coefficient of the
Weyl tensor squared contribution to the conformal anomaly. We also comment on
the implications of our results for the central charge a expected to be of
relevance for a four-dimensional C-theorem.Comment: 28 pages, LaTeX, no figure
A Massive Yang-Mills Theory based on the Nonlinearly Realized Gauge Group
We propose a subtraction scheme for a massive Yang-Mills theory realized via
a nonlinear representation of the gauge group (here SU(2)). It is based on the
subtraction of the poles in D-4 of the amplitudes, in dimensional
regularization, after a suitable normalization has been performed. Perturbation
theory is in the number of loops and the procedure is stable under iterative
subtraction of the poles. The unphysical Goldstone bosons, the Faddeev-Popov
ghosts and the unphysical mode of the gauge field are expected to cancel out in
the unitarity equation. The spontaneous symmetry breaking parameter is not a
physical variable. We use the tools already tested in the nonlinear sigma
model: hierarchy in the number of Goldstone boson legs and weak power-counting
property (finite number of independent divergent amplitudes at each order). It
is intriguing that the model is naturally based on the symmetry SU(2)_L local
times SU(2)_R global. By construction the physical amplitudes depend on the
mass and on the self-coupling constant of the gauge particle and moreover on
the scale parameter of the radiative corrections. The Feynman rules are in the
Landau gauge.Comment: 44 pages, 1 figure, minor changes, final version accepted by Phys.
Rev.
The Jackiw-Pi model and its symmetries
The non-Abelian gauge model proposed by Jackiw and Pi, which generates an
even-parity mass term in three space-time dimensions, is revisited in this
letter. All the symmetries of the model are collected and established by means
of BRS invariance and Slavnov-Taylor identity. The path for the perturbatively
quantization of the Jackiw-Pi model, through the algebraic method of
renormalization, is presented.Comment: 5 page
Anomalous Transformation in Supersymmetric Yang-Mills Theory
An ``anomalous'' supersymmetry transformation of the gaugino axial current is
given in supersymmetric Yang-Mills theory. The contact term is computed to
one-loop order by a gauge-invariant point-splitting procedure. We reexamine the
supercurrent anomaly in this method.Comment: 8 p
General Solution Of Linear Vector Supersymmetry
We give the general solution of the Ward identity for the linear vector
supersymmetry which characterizes all topological models. Such solution, whose
expression is quite compact and simple, greatly simplifies the study of
theories displaying a supersymmetric algebraic structure, reducing to a few
lines the proof of their possible finiteness. In particular, the cohomology
technology usually involved for the quantum extension of these theories, is
completely bypassed. The case of Chern-Simons theory is taken as an example.Comment: 18 pages, LaTeX, no figure
Notes on Operator Equations of Supercurrent Multiplets and the Anomaly Puzzle in Supersymmetric Field Theories
Recently, Komargodski and Seiberg have proposed a new type of supercurrent
multiplet which contains the energy-momentum tensor and the supersymmetry
current consistently. In this paper we study quantum properties of the
supercurrent in renormalizable field theories. We point out that the new
supercurrent gives a quite simple resolution to the classic problem, called the
anomaly puzzle, that the Adler-Bardeen theorem applied to an R-symmetry current
is inconsistent with all order corrections to functions. We propose an
operator equation for the supercurrent in all orders of perturbation theory,
and then perform several consistency checks of the equation. The operator
equation we propose is consisitent with the one proposed by Shifman and
Vainshtein, if we take some care in interpreting the meaning of non-conserved
currents.Comment: 28 pages; v2:clarifications and references added, some minor change
WT identities for proper vertices and renormalization in a superspace formulation of gauge theories
We formulate the WT identity for proper vertices in a simple and compact form
in a superspace formulation of gauge
theories proposed earlier. We show this WT identity (together with a subsidiary
constraint) lead, in transparent way, the superfield superspace multiplet
renormalizations formulated earlier (and shown to explain symmetries of
Yang-Mills theory renormalization).Comment: 18 pages, Latex , Revised version, Appeared in PRD 5
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