26,477 research outputs found
Quantum-Induced Soft Supersymmetry Breaking In Supergravity
We calculate the one-loop quantum contributions to soft supersymmetry
breaking terms in the scalar potential in supergravity theories regulated \`a
la Pauli-Villars. We find ``universal'' contributions, independent of the
regulator masses and tree level soft supersymmetry breaking, that contribute
gaugino masses and A-terms equal to the ``anomaly mediated'' contributions
found in analyses using spurion techniques, as well as a scalar mass term not
identified in those analyses. The universal terms are in general modified --
and in some cases canceled -- by model-dependent terms. Under certain
restrictions on the couplings we recover the one-loop results of previous
``anomaly mediated'' supersymmetry breaking scenarios. We emphasize the model
dependence of loop-induced soft terms in the potential, which are much more
sensitive to the details of Planck scale physics then are the one-loop
contributions to gaugino masses. We discuss the relation of our results to
previous analyses.Comment: 18 pages. This replacement corrects eqs. (7) and (31) and adds
clarifying comments after eq. (11) and before eq. (18
Anomaly Structure of Supergravity and Anomaly Cancellation
We display the full anomaly structure of supergravity, including new D-term
contributions to the conformal anomaly. This expression has the super-Weyl and
chiral U(1)_K transformation properties that are required for implementation of
the Green-Schwarz mechanism for anomaly cancellation. We outline the procedure
for full anomaly cancellation. Our results have implications for effective
supergravity theories from the weakly coupled heterotic string theory.Comment: 8 page
Effective Supergravity from the Weakly Coupled Heterotic String
The motivation for Calabi-Yau-like compactifications of the weakly coupled
heterotic string theory, its particle spectrum and the issue
of dilaton stabilization are briefly reviewed. Modular invariant models for
hidden sector condensation and supersymmetry breaking are described at the
quantum level of the effective field theory. Their phenomenological and
cosmological implications, including a possible origin for R-parity, are
discussed.Comment: 17 pages, Talk presented at the Symposium in honor of Julius Wess,
Jan. 10--11, 200
The Axion Mass in Modular Invariant Supergravity
When supersymmetry is broken by condensates with a single condensing gauge
group, there is a nonanomalous R-symmetry that prevents the universal axion
from acquiring a mass. It has been argued that, in the context of supergravity,
higher dimension operators will break this symmetry and may generate an axion
mass too large to allow the identification of the universal axion with the QCD
axion. We show that such contributions to the axion mass are highly suppressed
in a class of models where the effective Lagrangian for gaugino and matter
condensation respects modular invariance (T-duality).Comment: 10 page
One Loop Soft Supersymmetry Breaking Terms in Superstring Effective Theories
We perform a systematic analysis of soft supersymmetry breaking terms at the
one loop level in a large class of string effective field theories. This
includes the so-called anomaly mediated contributions. We illustrate our
results for several classes of orbifold models. In particular, we discuss a
class of models where soft supersymmetry breaking terms are determined by quasi
model independent anomaly mediated contributions, with possibly non-vanishing
scalar masses at the one loop level. We show that the latter contribution
depends on the detailed prescription of the regularization process which is
assumed to represent the Planck scale physics of the underlying fundamental
theory. The usual anomaly mediation case with vanishing scalar masses at one
loop is not found to be generic. However gaugino masses and A-terms always
vanish at tree level if supersymmetry breaking is moduli dominated with the
moduli stabilized at self-dual points, whereas the vanishing of the B-term
depends on the origin of the mu-term in the underlying theory. We also discuss
the supersymmetric spectrum of O-I and O-II models, as well as a model of
gaugino condensation. For reference, explicit spectra corresponding to a Higgs
mass of 114 GeV are given. Finally, we address general strategies for
distinguishing among these models.Comment: 49 pages: includes three tables and nine figure
On Quadratic Divergences in Supergravity, Vacuum Energy and the Supersymmetric Flavor Problem
We examine the phenomenological consequences of quadratically divergent
contributions to the scalar potential in supergravity effective Lagrangians. We
focus specifically on the effect of these corrections on the vacuum
configuration of scalar fields in softly-broken supersymmetric theories and the
role these corrections play in generating non-diagonal soft scalar masses. Both
effects can only be properly studied when the divergences are regulated in a
manifestly supersymmetric manner -- something which has thus far been neglected
in past treatments. We show how a supersymmetric regularization can impact past
conclusions about both types of phenomena and discuss what types of high-energy
theories are likely to be safe from unwanted flavor-changing neutral current
interactions in the context of supergravity theories derived from heterotic
string compactifications
Multi-parametric solutions to the NLS equation
The structure of the solutions to the one dimensional focusing nonlin-ear
Schr{\"o}dinger equation (NLS) for the order N in terms of quasi rational
functions is given here. We first give the proof that the solutions can be
expressed as a ratio of two wronskians of order 2N and then two determinants by
an exponential depending on t with 2N -- 2 parameters. It also is proved that
for the order N , the solutions can be written as the product of an exponential
depending on t by a quotient of two polynomials of degree N (N + 1) in x and t.
The solutions depend on 2N -- 2 parameters and give when all these parameters
are equal to 0, the analogue of the famous Peregrine breather PN. It is
fundamental to note that in this representation at order N , all these
solutions can be seen as deformations with 2N -- 2 parameters of the famous
Peregrine breather PN. With this method, we already built Peregrine breathers
until order N = 10, and their deformations depending on 2N -- 2 parameters
R-parity from the heterotic string
In T-duality invariant effective supergravity with gaugino condensation as
the mechanism for supersymmetry breaking, there is a residual discrete symmetry
that could play the role of R-parity in supersymmetric extensions of the
Standard Model.Comment: 9 page
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