166 research outputs found
Nonrenormalization theorems for N=2 Super Yang-Mills
The BRST algebraic proofs of the the nonrenormalization theorems for the beta
functions of N=2 and N=4 Super Yang-Mills theories are reviewed.Comment: 3 pages, contribution to SUSY 2000 Encyclopedi
Study of the Gribov region in Euclidean Yang-Mills theories in the maximal Abelian gauge
The properties of the Gribov region in SU(2) Euclidean Yang-Mills theories in
the maximal Abelian gauge are investigated. This region turns out to be bounded
in all off-diagonal directions, while it is unbounded along the diagonal one.
The soft breaking of the BRST invariance due to the restriction of the domain
of integration in the path integral to the Gribov region is scrutinized. Owing
to the unboundedness in the diagonal direction, the invariance with respect to
Abelian transformations is preserved, a property which is at the origin of the
local U(1) Ward identity of the maximal Abelian gauge.Comment: 15 pages, one reference added, version accepted for publication in
Phys. Rev.
The action of N=4 Super Yang-Mills from a chiral primary operator
Using the Vafa-Witten twisted version of N=4 Super Yang-Mills a subset of the
supercharges actually relevant for the nonrenormalization properties of the
theory is identified. In particular, a relationship between the gauge-fixed
action and the chiral primary operator tr(\phi)^2 is worked out. This result
can be understood as an off-shell extension of the reduction formula introduced
by Intriligator.Comment: 1+15 pages, LaTeX2e, one reference changed, a footnote adde
The gluon and ghost propagators in Euclidean Yang-Mills theory in the maximal Abelian gauge: taking into account the effects of the Gribov copies and of the dimension two condensates
The infrared behavior of the gluon and ghost propagators is studied in SU(2)
Euclidean Yang-Mills theory in the maximal Abelian gauge within the
Gribov-Zwanziger framework. The nonperturbative effects associated with the
Gribov copies and with the dimension two condensates are simultaneously encoded
into a local and renormalizable Lagrangian. The resulting behavior turns out to
be in good agreement with the lattice data.Comment: final version, to appear in Physical Review
An Algebraic Criterion for the Ultraviolet Finiteness of Quantum Field Theories
An algebraic criterion for the vanishing of the beta function for
renormalizable quantum field theories is presented. Use is made of the descent
equations following from the Wess-Zumino consistency condition. In some cases,
these equations relate the fully quantized action to a local gauge invariant
polynomial. The vanishing of the anomalous dimension of this polynomial enables
us to establish a nonrenormalization theorem for the beta function ,
stating that if the one-loop order contribution vanishes, then will
vanish to all orders of perturbation theory. As a by-product, the special case
in which is only of one-loop order, without further corrections, is
also covered. The examples of the N=2,4 supersymmetric Yang-Mills theories are
worked out in detail.Comment: 1+32 pages, LaTeX2e, typos correcte
A BRST Characterization of the Broken Phase Observables of the Confining Complex Theory
Some time ago we have introduced a route to provide confinement in the sense
that particle excitations would appear from condensates of fields that do not
have physical asymptotic states. We envisaged this mechanism in an asymmetric
vacuum phase of a complex gauge field theory. More recently, we showed how to
define a BRST operator to the broken phase of a generic spontaneous broken
field theory. Our intention here is to apply these late concepts to the
previous complex field theory in order to give a cohomological characterization
of those condensed states as actual physical observables of this theory in its
broken phase.Comment: 2 figures, 12 page
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.
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