542 research outputs found
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
Planar Gravitational Corrections For Supersymmetric Gauge Theories
In this paper we discuss the contribution of planar diagrams to gravitational
F-terms for N=1 supersymmetric gauge theories admitting a large N description.
We show how the planar diagrams lead to a universal contribution at the
extremum of the glueball superpotential, leaving only the genus one
contributions, as was previously conjectured. We also discuss the physical
meaning of gravitational F-terms.Comment: 20 pages, 4 figure
T-Duality in the Green-Schwarz Formalism, and the Massless/Massive IIA Duality Map
We derive a component-field expansion of the Green-Schwarz action for the
type IIA string, in an arbitrary background of massless NS-NS and R-R bosonic
fields, up to quadratic order in the fermionic coordinates \theta. Using this
action, we extend the usual derivation of Buscher T-duality rules to include
not only NS-NS, but also R-R fields. Our implementation of the T-duality
transformation rules makes use of adapted background-field parametrizations,
which provide a more geometrically natural and elegant description for the
duality maps than the ones previously presented. These T-duality rules allow us
to derive the Green-Schwarz action for the type IIB string in an arbitrary
background of massless NS-NS and R-R bosonic fields, up to O(\theta^2).
Implemention of another T-duality transformation on this type IIB action then
allows us also to derive the Green-Schwarz action for the massive IIA string.
By further considering T-duality transformations for backgrounds with the two
U(1) isometries of a 2-torus, we give a string-theoretic derivation of the
direct T-duality relation between the massless and massive type IIA strings. In
addition, we give an explicit construction of the D=8 SL(3,R)xSL(2,R) invariant
supergravity with two mass parameters that form a doublet under the SL(2,R)
factor.Comment: Latex, 34 pages. Minor typographical corrections, and various
improvements to notation and conventions. Detailed discussion of changes
given in Addendum sectio
Factorization in graviton interactions
The study of factorization in the linearized gravity is extended to the
graviton scattering processes with a massive scalar particle, with a massless
vector boson and also with a graviton. Every transition amplitude is shown to
be completely factorized and the physical implications of their common factors
are discussed.Comment: 5 pages, Revtex 3.0, SNUTP 93-7
Non(anti)commutative SYM theory: Renormalization in superspace
We present a systematic investigation of one-loop renormalizability for
nonanticommutative N=1/2, U(N) SYM theory in superspace. We first discuss
classical gauge invariance of the pure gauge theory and show that in
contradistinction to the ordinary anticommutative case, different
representations of supercovariant derivatives and field strengths do not lead
to equivalent descriptions of the theory. Subsequently we develop background
field methods which allow us to compute a manifestly covariant gauge effective
action. One-loop evaluation of divergent contributions reveals that the theory
simply obtained from the ordinary one by trading products for star products is
not renormalizable. In the case of SYM with no matter we present a N=1/2
improved action which we show to be one-loop renormalizable and which is
perfectly compatible with the algebraic structure of the star product. For this
action we compute the beta functions. A brief discussion on the inclusion of
chiral matter is also presented.Comment: Latex file, 59 pages, 10 figures, One reference adde
One-loop divergences in the two-dimensional non-anticommutative supersymmetric sigma-model
We discuss the structure of the non-anticommutative N=2 non-linear
sigma-model in two dimensions, constructing differential operators which
implement the deformed supersymmetry generators and using them to reproduce the
classical action. We then compute the one-loop quantum corrections and express
them in a more compact form using the differential operators.Comment: 20pp, 8 figures, uses LaTeX. Title expanded to clarify conten
Clarifying Some Remaining Questions in the Anomaly Puzzle
We discuss several points that may help to clarify some questions that remain
about the anomaly puzzle in supersymmetric theories. In particular, we consider
a general N=1 supersymmetric Yang-Mills theory. The anomaly puzzle concerns the
question of whether there is a consistent way to put the R-current and the
stress tensor in a single supercurrent, even though in the classical theory
they are in the same supermultiplet. As is well known, the classically
conserved supercurrent bifurcates into two supercurrents having different
anomalies in the quantum regime. The most interesting result we obtain is an
explicit expression for the lowest component of one of the two supercurrents in
4-dimensional spacetime, namely the supercurrent that has the energy-momentum
tensor as one of its components. This expression for the lowest component is an
energy-dependent linear combination of two chiral currents, which itself does
not correspond to a classically conserved chiral current. The lowest component
of the other supercurrent, namely, the R-current, satisfies the Adler-Bardeen
theorem. The lowest component of the first supercurrent has an anomaly that we
show is consistent with the anomaly of the trace of the energy-momentum tensor.
Therefore, we conclude that there is no consistent way to put the R-current and
the stress tensor in a single supercurrent in the quantized theory. We also
discuss and try to clarify some technical points in the derivations of the
two-supercurrents in the literature. These latter points concern the
significance of infrared contributions to the NSVZ beta-function and the role
of the equations of motion in deriving the two supercurrents.Comment: 22 pages, no figure. v2: minor changes. v3: sections re-organized.
new subsections (IVA, IVB) added. references adde
The Supersymmetric Effective Action of the Heterotic String in Ten Dimensions
We construct the supersymmetric completion of quartic -actions in the
ten-dimensional effective action of the heterotic string. Two invariants, of
which the bosonic parts are known from one-loop string amplitude calculations,
are obtained. One of these invariants can be generalized to an
-invariant for supersymmetric Yang-Mills theory coupled to
supergravity.
Supersymmetry requires the presence of -terms, ( for
Yang-Mills) which correspond to counterterms in the Green-Schwarz anomaly
cancellation. Within the context of our calculation the -term from
the tree-level string effective action does not allow supersymmetrization.Comment: 42 pages, UG-9/9
Boundary S matrices for the open Hubbard chain with boundary fields
Using the method introduced by Grisaru et al., boundary S matrices for the
physical excitations of the open Hubbard chain with boundary fields are
studied. In contrast to the open supersymmetric t-J model, the boundary S
matrix for the charge excitations depend on the boundary fields though the
boundary fields do not break the spin-SU(2) symmetry.Comment: Latex,12 page
Bubbling Geometries for Half BPS Wilson lines
We consider the supergravity backgrounds that correspond to supersymmetric
Wilson line operators in the context of AdS/CFT correspondence. We study the
gravitino and dilatino conditions of the IIB supergravity under the appropriate
ansatz, and obtain some necessary conditions for a supergravity background that
preserves the same symmetry as the supersymmetric Wilson lines. The
supergravity solutions are characterized by continuous version of maya
diagrams. This diagram is related to the eigenvalue distribution of the
Gaussian matrix model. We also consider the similar backgrounds of the
11-dimensional supergravity.Comment: 25 pages, 9 figures. v2:typos corrected. v3:added the differential
conditions and comments at the end of section 2. typos correcte
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