133 research outputs found
Electric Dipole Moments in Natural Supersymmetry
We discuss electric dipole moments (EDMs) in the framework of CP-violating
natural supersymmetry (SUSY). Recent experimental results have significantly
tightened constraints on the EDMs of electrons and of mercury, and substantial
further progress is expected in the near future. We assess how these results
constrain the parameter space of natural SUSY. In addition to our discussion of
SUSY, we provide a set of general formulas for two-loop fermion EDMs, which can
be applied to a wide range of models of new physics. In the SUSY context, the
two-loop effects of stops and charginos respectively constrain the phases of
and to be small in the natural part of parameter space. If
the Higgs mass is lifted to 125 GeV by a new tree-level superpotential
interaction and soft term with CP-violating phases, significant EDMs can arise
from the two-loop effects of bosons and tops. We compare the bounds arising
from EDMs to those from other probes of new physics including colliders, , and dark matter searches. Importantly, improvements in reach not
only constrain higher masses, but require the phases to be significantly
smaller in the natural parameter space at low mass. The required smallness of
phases sharpens the CP problem of natural SUSY model building.Comment: 37 pages plus appendices, 16 figures; v2: journal versio
Inflation and Gauge Mediation in Supersymmetric Gauge Theory
We propose a simple high-scale inflationary scenario based on a
phenomenologically viable model with direct gauge mediation of low-scale
supersymmetry breaking. Hybrid inflation is occurred in a hidden supersymmetry
breaking sector. Two hierarchical mass scales to reconcile both high-scale
inflation and gauge mediation are necessary for the stability of the metastable
supersymmetry breaking vacuum. Our scenario is also natural in light of the
Landau pole problem of direct gauge mediation.Comment: 10 pages; v2: presentation changed, qualitative results unchanged,
references added; v3: minor correction, published in PT
Natural Supersymmetry in Warped Space
We explore the possibility of solving the hierarchy problem by combining the
paradigms of supersymmetry and compositeness. Both paradigms are under pressure
from the results of the Large Hadron Collider (LHC), and combining them allows
both a higher confinement scale -- due to effective supersymmetry in the low
energy theory -- and heavier superpartners -- due to the composite nature of
the Higgs boson -- without sacrificing naturalness. The supersymmetric
Randall-Sundrum model provides a concrete example where calculations are
possible, and we pursue a realistic model in this context. With a few
assumptions, we are led to a model with bulk fermions, a left-right gauge
symmetry in the bulk, and supersymmetry breaking on the UV brane. The first two
generations of squarks are decoupled, reducing LHC signatures but also leading
to quadratic divergences at two loops. The model predicts light and
gauge bosons, and present LHC constraints on exotic gauge bosons imply a high
confinement scale and mild tuning from the quadratic divergences, but the model
is otherwise viable. We also point out that R-parity violation can arise
naturally in this context.Comment: 60 pages, 7 figures; v2: minor changes, references added, published
versio
- …