22 research outputs found
Decoupling Solution to SUSY Flavor Problem via Extra Dimensions
We discuss the decoupling solution to SUSY flavor problem in the fat brane
scenario. We present a simple model to yield the decoupling sfermion spectrum
in a five dimensional theory. Sfermion masses are generated by the overlap
between the wave functions of the matter fields and the chiral superfields on
the SUSY breaking brane. Two explicit examples of the spectrum are given.Comment: 8 pages, LaTe
(S)fermion Masses in Fat Brane Scenario
We discuss the fermion mass hierarchy and the flavor mixings in the fat brane
scenario of a five dimensional SUSY theory. Assuming that the matter fields
lives in the bulk, their zero mode wave functions are Gaussians, and Higgs
fields are localized on the brane, we find simple various types of the matter
configurations generating the mass matrices consistent with experimental data.
Sfermion mass spectrum is also discussed using the matter configurations found
above. Which type of squark mass spectra (the degeneracy, the decoupling and
the alignment) is realized depends on the relative locations of SUSY breaking
brane and the brane where Higgs fields are localized.Comment: 18 pages, LaTe
Aspects of Phase Transition in Gauge-Higgs Unification at Finite Temperature
We study the phase transition in gauge-Higgs unification at finite
temperature. In particular, we obtain the strong first order electroweak phase
transition for a simple matter content yielding the correct order of Higgs mass
at zero temperature. Two stage phase transition is found for a particular
matter content, which is the strong first order at each stage. We further study
supersymmetric gauge models with the Scherk-Schwarz supersymmetry breaking. We
again observe the first order electroweak phase transition and multi stage
phase transition.Comment: 18 pages, 7 figures, references corrected, minor correctio
Finite Gluon Fusion Amplitude in the Gauge-Higgs Unification
We show that the gluon fusion amplitude in the gauge-Higgs unification
scenario is finite in any dimension regardless of its nonrenormalizability.
This result is supported by the fact that the local operator describing the
gluon fusion process is forbidden by the higher dimensional gauge invariance.
We explicitly calculate the gluon fusion amplitude in an arbitrary dimensional
gauge-Higgs unification model and indeed obtain the finite result.Comment: 15 pages, final version to appear in MPL
Gauge-Higgs Dark Matter
When the anti-periodic boundary condition is imposed for a bulk field in
extradimensional theories, independently of the background metric, the lightest
component in the anti-periodic field becomes stable and hence a good candidate
for the dark matter in the effective 4D theory due to the remaining accidental
discrete symmetry. Noting that in the gauge-Higgs unification scenario,
introduction of anti-periodic fermions is well-motivated by a phenomenological
reason, we investigate dark matter physics in the scenario. As an example, we
consider a five-dimensional SO(5)\timesU(1)_X gauge-Higgs unification model
compactified on the with the warped metric. Due to the structure of
the gauge-Higgs unification, interactions between the dark matter particle and
the Standard Model particles are largely controlled by the gauge symmetry, and
hence the model has a strong predictive power for the dark matter physics.
Evaluating the dark matter relic abundance, we identify a parameter region
consistent with the current observations. Furthermore, we calculate the elastic
scattering cross section between the dark matter particle and nucleon and find
that a part of the parameter region is already excluded by the current
experimental results for the direct dark matter search and most of the region
will be explored in future experiments.Comment: 16 pages, 2 figure
Realistic construction of split fermion models
The Standard Model flavor structure can be explained in theories where the
fermions are localized on different points in a compact extra dimension. We
show that models with two bulk scalars compactified on an orbifold can produce
such separations in a natural way. We study the shapes and overlaps of the
fermion wave functions. We show that, generically, realistic models of Gaussian
overlaps are unnatural since they require very large Yukawa couplings between
the fermions and the bulk scalars. We give an example of a five dimensional two
scalar model that accounts naturally for the observed quark masses, mixing
angles and CP violation.Comment: 15 pages, 5 figures, typos corrected, discussion on the implications
of SM rare decay processes added, to appear in PR
Solitonic supersymmetry restoration
Q-balls are a possible feature of any model with a conserved, global U(1)
symmetry and no massless, charged scalars. It is shown that for a broad class
of models of metastable supersymmetry breaking they are extremely influential
on the vacuum lifetime and make seemingly viable vacua catastrophically short
lived. A net charge asymmetry is not required as there is often a significant
range of parameter space where statistical fluctuations alone are sufficient.
This effect is examined for two supersymmetry breaking scenarios. It is found
that models of minimal gauge mediation (which necessarily have a messenger
number U(1)) undergo a rapid, supersymmetry restoring phase transition unless
the messenger mass is greater than 10^8 GeV. Similarly the ISS model, in the
context of direct mediation, quickly decays unless the perturbative
superpotential coupling is greater than the Standard Model gauge couplings.Comment: 17 pages, 3 figures, minor comments added, accepted for publication
in JHE
Dynamical completions of generalized O'Raifeartaigh models
We present gauge theory completions of Wess-Zumino models admitting
supersymmetry breaking vacua with spontaneously broken R-symmetry. Our models
are simple deformations of generalized ITIY models, a supersymmetric theory
with gauge group Sp(N), N+1 flavors plus singlets, with a modified tree level
superpotential which explicitly breaks (part of) the global symmetry. Depending
on the nature of the deformation, we obtain effective O'Raifeartaigh-like
models whose pseudomoduli space is locally stable in a neighborhood of the
origin of field space, or in a region not including it. Hence, once embedded in
direct gauge mediation scenarios, our models can give low energy spectra with
either suppressed or unsuppressed gaugino mass.Comment: 21 pages, 1 figure; v3: reference adde
An Extension for Direct Gauge Mediation of Metastable Supersymmetry Breaking
We study the direct mediation of metastable supersymmetry breaking by a
\Phi^2-deformation to the ISS model and extend it by splitting both Tr\Phi and
Tr\Phi^2 terms in the superpotential and gauging the flavor symmetry. We find
that with such an extension the enough long-lived metastable vacua can be
obtained and the proper gaugino masses can be generated. Also, this allows for
constructing a kind of models which can avoid the Landau pole problem.
Especially, in our metastable vacua there exist a large region for the
parameter m_3 which can satisfy the phenomenology requirements and allow for a
low SUSY breaking scale (\sim 100 TeV).Comment: version in Europhys. Let
The Discrete Composite Higgs Model
We describe a concrete, predictive incarnation of the general paradigm of a
composite Higgs boson, which provides a valid alternative to the standard
holographic models in five space-time dimensions. Differently from the latter,
our model is four-dimensional and simple enough to be implemented in an event
generator for collider studies. The model is inspired by dimensional
deconstruction and hence it retains useful features of the five-dimensional
scenario, in particular, the Higgs potential is finite and calculable.
Therefore our setup, in spite of being simple, provides a complete description
of the composite Higgs physics. After constructing the model we present a first
analysis of its phenomenology, focusing on the structure of the Higgs
potential, on the constraints from the EWPT and on the spectrum of the new
particles.Comment: 42 pages, 10 figures; v2: minor changes and references added; v3:
version published in JHE