2,675 research outputs found
Realistic Anomaly Mediation with Bulk Gauge Fields
We present a simple general framework for realistic models of supersymmetry
breaking driven by anomaly mediation. We consider a 5-dimensional "brane
universe" where the visible and hidden sectors are localized on different
branes, and the standard model gauge bosons propagate in the bulk. In this
framework there can be charged scalar messengers that have contact interactions
with the hidden sector, either localized in the hidden sector or in the bulk.
These scalars obtain soft masses that feed into visible sector scalar masses at
two loop order via bulk gauge interactions. This contribution is automatically
flavor-blind, and can be naturally positive. If the messengers are in the bulk
this contribution is automatically the same order of magnitude as the anomaly
mediated contribution, independent of the brane spacing. If the messengers are
localized to a brane the two effects are of the same order for relatively small
brane spacings. The gaugino masses and A terms are determined completely by
anomaly mediation. In order for anomaly mediation to dominate over radion
mediation the radion must be is stabilized in a manner that preserves
supersymmetry, with supergravity effects included. We show that this occurs in
simple models. We also show that the mu problem can be solved by the vacuum
expectation value of a singlet in this framework.Comment: 16 pages, LaTeX2e, no figure
Radion Mediated Supersymmetry Breaking
We point out that in supersymmetric theories with extra dimensions, radius
stabilization can give rise to a VEV for the component of the radius
modulus. This gives an important contribution to supersymmetry breaking of
fields that propagate in the bulk. A particularly attractive class of models is
obtained if the standard-model gauge fields propagate in the bulk, while the
quark and lepton fields are localized on a brane. This leads to gaugino
mediated supersymmetry breaking without the need for singlets in the hidden
sector. We analyze a simple explicit model in which this idea is realized
Calculable Dynamical Supersymmetry Breaking on Deformed Moduli Spaces
We consider models of dynamical supersymmetry breaking in which the
extremization of a tree-level superpotential conflicts with a quantum
constraint. We show that in such models the low-energy effective theory near
the origin of moduli space is an O'Raifeartaigh model, and the sign of the
mass-squared for the pseudo-flat direction at the origin is calculable. We
analyze vector-like models with gauge groups SU(N) and Sp(2N) with and without
global symmetries. In all cases there is a stable minimum at the origin with an
unbroken U(1)_R symmetry.Comment: 8 pages, LaTeX2e, no figure
Realistic Anomaly-mediated Supersymmetry Breaking
We consider supersymmetry breaking communicated entirely by the
superconformal anomaly in supergravity. This scenario is naturally realized if
supersymmetry is broken in a hidden sector whose couplings to the observable
sector are suppressed by more than powers of the Planck scale, as occurs if
supersymmetry is broken in a parallel universe living in extra dimensions. This
scenario is extremely predictive: soft supersymmetry breaking couplings are
completely determined by anomalous dimensions in the effective theory at the
weak scale. Gaugino and scalar masses are naturally of the same order, and
flavor-changing neutral currents are automatically suppressed. The most glaring
problem with this scenario is that slepton masses are negative in the minimal
supersymmetric standard model. We point out that this problem can be simply
solved by coupling extra Higgs doublets to the leptons. Lepton flavor-changing
neutral currents can be naturally avoided by approximate symmetries. We also
describe more speculative solutions involving compositeness near the weak
scale. We then turn to electroweak symmetry breaking. Adding an explicit \mu
term gives a value for B\mu that is too large by a factor of order 100. We
construct a realistic model in which the \mu term arises from the vacuum
expectation value of a singlet field, so all weak-scale masses are directly
related to m_{3/2}. We show that fully realistic electroweak symmetry breaking
can occur in this model with moderate fine-tuning.Comment: 32 pages, LaTeX2e, 3 eps figure
The relationship of the Hebrew priesthood to the Canaanite priesthood
https://place.asburyseminary.edu/ecommonsatsdissertations/1928/thumbnail.jp
Gaugino Mediated Supersymmetry Breaking
We consider supersymmetric theories where the standard-model quark and lepton
fields are localized on a "3-brane" in extra dimensions, while the gauge and
Higgs fields propagate in the bulk. If supersymmetry is broken on another
3-brane, supersymmetry breaking is communicated to gauge and Higgs fields by
direct higher-dimension interactions, and to quark and lepton fields via
standard-model loops. We show that this gives rise to a realistic and
predictive model for supersymmetry breaking. The size of the extra dimensions
is required to be of order 10-100 times larger than fundamental scale (e.g. the
string scale). The spectrum is similar to (but distinguishable from) the
predictions of "no-scale" models. Flavor-changing neutral currents are
naturally suppressed. The \mu term can be generated by the Giudice-Masiero
mechanism. The supersymmetric CP problem is naturally solved if CP violation
occurs only on the observable sector 3-brane. These are the simplest models in
the literature that solve all supersymmetric naturalness problems.Comment: Refs. added. 12 pages, 1 figur
The natural/neglected relationship: liberalism, identity and India-Australia relations
Published online: 27 Oct 2015Recent commentary on India–Australia relations has defined the relationship as ‘natural’ and based on ‘shared values’ and ‘shared history’. The relationship has simultaneously been considered ‘neglected’. The paradoxical juxtaposition of a natural/neglected partnership is yet to be adequately explained. We consider the historical construction of liberalism in both states as a facet of state identity to argue that, far from creating a natural relationship, differing liberal identities have served to keep these two states apart. This is illustrated through case studies of divergent opinions over the Nuclear Non-Proliferation Treaty, Russia's 2014 annexation of Crimea and the rise of China.Priya Chacko & Alexander E. Davi
Supersymmetry in Slow Motion
We construct new theories of electroweak symmetry breaking that employ a
combination of supersymmetry and discrete symmetries to stabilize the weak
scale up to and beyond the energies probed by the LHC. These models exhibit
conventional supersymmetric spectra but the fermion-sfermion-gaugino vertices
are absent. This closes many conventional decay channels, thereby allowing
several superpartners to be stable on collider time scales. This opens the door
to the possibility of directly observing R-hadrons and three flavors of
sleptons inside the LHC detectors.Comment: A reference added. The discussion on the Higgs sector expanded. The
version accepted for publication in JHE
Associated production of the charged Higgs boson and single top quark at the LHC
The left-right twin Higgs(LRTH) model predicts the existence of the charged
Higgs . In this paper, we study the production of the charged Higgs
boson with single top quark via the process at the
Large Hadron Collider(LHC). The numerical results show that the
production cross section can reach the level of in the reasonable
parameter space of the LRTH model. We expect that, as long as it is not too
heavy, the possible signatures of the heavy charged Higgs boson
might be detected via the decay mode at the LHC
experiments.Comment: This paper has been withdrawn by the author(s) due to some mistakes
in this pape
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