31 research outputs found
Gauged supersymmetric \gs--models and soft breaking terms
Supersymmetric non--linear \gs--models in four dimensions with a --term
potentials can sometimes have singular kinetic metric terms. As the kinetic
terms of scalar fields and their chiral fermionic partners are determine by
this metric, it follow that their kinetic energy vanishes in the vacuum. In
previous work, it has been shown in a simple model that soft supersymmetry
breaking terms can lift the degenerate the sigma-model metric and provide a
consistent mass-spectra. In this letter I introduce soft breaking terms in a
more realistic models based on SO(10) and and compute the resulting mass
spectrum.Comment: Latex 6 pages, added references, typos corrected; final published
versio
Fluid Super-Dynamics from Black Hole Superpartners
Recently the Navier-Stokes equations have been derived from the duality with
the black branes in AdS_5. The zero modes of black branes are reinterpreted as
dynamical degrees of freedom of a conformal fluid on the boundary of AdS_5.
Here, we derive the corrections to the Navier-Stokes equations due to fermionic
zero modes of the black branes. We study only the contributions due to
bilinears in the fermionic zero modes in the first order of the parameter
expansion. The need of a superextension of the fluid dynamics is a consequence
of the full AdS/CFT correspondence and yet to be investigated.Comment: 15 pages, LaTex2
Effective Action of Softly Broken Supersymmetric Theories
We study the renormalization of (softly) broken supersymmetric theories at
the one loop level in detail. We perform this analysis in a superspace approach
in which the supersymmetry breaking interactions are parameterized using
spurion insertions. We comment on the uniqueness of this parameterization. We
compute the one loop renormalization of such theories by calculating superspace
vacuum graphs with multiple spurion insertions. To preform this computation
efficiently we develop algebraic properties of spurion operators, that
naturally arise because the spurions are often surrounded by superspace
projection operators. Our results are general apart from the restrictions that
higher super covariant derivative terms and some finite effects due to
non-commutativity of superfield dependent mass matrices are ignored. One of the
soft potentials induces renormalization of the Kaehler potential.Comment: 1+28 pages LaTeX, A few references adde
Singular supersymmetric sigma models
Supersymmetric non-linear sigma-models are described by a field dependent
Kaehler metric determining the kinetic terms. In general it is not guaranteed
that this metric is always invertible. Our aim is to investigate the symmetry
structure of supersymmetric models in four dimensional space-time in which
metric singularities occur. For this purpose we study a simple anomaly-free
extension of the supersymmetric CP^1 model from a classical point of view. We
show that the metric singularities can be regularized by the addition of a soft
supersymmetry-breaking mass parameter.Comment: 21 pages, no figure
Two loop effective kaehler potential of (non-)renormalizable supersymmetric models
We perform a supergraph computation of the effective Kaehler potential at one
and two loops for general four dimensional N=1 supersymmetric theories
described by arbitrary Kaehler potential, superpotential and gauge kinetic
function. We only insist on gauge invariance of the Kaehler potential and the
superpotential as we heavily rely on its consequences in the quantum theory.
However, we do not require gauge invariance for the gauge kinetic functions, so
that our results can also be applied to anomalous theories that involve the
Green-Schwarz mechanism. We illustrate our two loop results by considering a
few simple models: the (non-)renormalizable Wess-Zumino model and Super Quantum
Electrodynamics.Comment: 1+26 pages, LaTeX, 6 figures; a missing diagram added and typos
correcte