1,783 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
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
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
The GUT Scale and Superpartner Masses from Anomaly Mediated Supersymmetry Breaking
We consider models of anomaly-mediated supersymmetry breaking (AMSB) in which
the grand unification (GUT) scale is determined by the vacuum expectation value
of a chiral superfield. If the anomaly-mediated contributions to the potential
are balanced by gravitational-strength interactions, we find a
model-independent prediction for the GUT scale of order . The GUT threshold also affects superpartner masses, and can easily
give rise to realistic predictions if the GUT gauge group is asymptotically
free. We give an explicit example of a model with these features, in which the
doublet-triplet splitting problem is solved. The resulting superpartner
spectrum is very different from that of previously considered AMSB models, with
gaugino masses typically unifying at the GUT scale.Comment: 17 page
Gauge/Anomaly Syzygy and Generalized Brane World Models of Supersymmetry Breaking
In theories in which SUSY is broken on a brane separated from the MSSM matter
fields, supersymmetry breaking is naturally mediated in a variety of ways.
Absent other light fields in the theory, gravity will mediate supersymmetry
breaking through the conformal anomaly. If gauge fields propagate in the extra
dimension they, too, can mediate supersymmetry breaking effects. The presence
of gauge fields in the bulk motivates us to consider the effects of new
messenger fields with holomorphic and non-holomorphic couplings to the
supersymmetry breaking sector. These can lead to contributions to the soft
masses of MSSM fields which dramatically alter the features of brane world
scenarios of supersymmetry breaking. In particular, they can solve the negative
slepton mass squared problem of anomaly mediation and change the predictions of
gaugino mediation.Comment: 4 pages, RevTe
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