89 research outputs found
Extracting Flavor from Quiver Gauge Theories
We consider a large class of models where an SU(5) gauge symmetry and a
Froggatt-Nielsen (FN) Abelian flavor symmetry arise from a quiver gauge theory.
Such quiver models are very restrictive and therefore have strong predictive
power. In particular, under mild assumptions neutrino mass anarchy is
predicted.Comment: 4 pages, 1 figure, to appear in Proceedings of SUSY06, the 14th
International Conference on Supersymmetry and the Unification of Fundamental
Interactions, UC Irvine, California, 12-17 June 200
Implications of Higgs Searches on the Four Generation Standard Model
Within the four generation Standard Model, the Higgs couplings to gluons and
to photons deviate in a significant way from the predictions of the three
generation Standard Model. As a consequence, large departures in several Higgs
production and decay channels are expected. Recent Higgs search results,
presented by ATLAS, CMS and CDF, hint on the existence of a Higgs boson with a
mass around 125 GeV. Using these results and assuming such a Higgs boson, we
derive exclusion limits on the four generation Standard Model. For m_H = 125
GeV, the model is excluded at 99.9% confidence level. For 124 GeV <= m_H <= 127
GeV, an exclusion limit above 95% confidence level is found.Comment: 4 pages, 2 figures; v2: updated LHC results, refined sca
Semi-direct Gauge Mediation
We describe a framework for gauge mediation of supersymmetry breaking in
which the messengers are charged under the hidden sector gauge group but do not
play a role in breaking supersymmetry. From this point of view, our framework
is between ordinary gauge mediation and direct mediation. As an example, we
consider the 3-2 model of dynamical supersymmetry breaking, and add to it
massive messengers which are SU(2) doublets. We briefly discuss the
phenomenology of this scenario.Comment: 24 pages. v2: Typos corrected and reference added. v3: Reference
adde
Hybrid Inflation and the Moduli Problem
We revisit some questions in supersymmetric hybrid inflation (SHI). We
analyze the amount of fine tuning required in various models, the problem of
decay at the end of inflation and the generation of baryons after inflation. We
find that the most natural setting for HI is in supersymmetric models with
non-renormalizable couplings. Furthermore, we argue that almost inevitably, one
of the fields involved is a modulus, with Planck scale variation. The resulting
moduli problem can be solved in two ways: either by a massive modulus (which
requires some fine tuning), or an enhanced symmetry point, in which the moduli
becomes strongly coupled to the Standard Model. Various possibilities for
baryon production are discussed.Comment: 19 page
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