82 research outputs found
Anomaly Mediation from Randall-Sundrum to Dine-Seiberg
In this paper we reconsider the derivation of anomaly mediated supersymmetry
breaking. We work in a general formalism where the F-term of the conformal
compensator superfield is arbitrary. This allows for a continuous interpolation
between the original derivation and a more recent Dine-Seiberg derivation of
anomaly mediation. We show that the physical soft parameters are independent of
the compensator F-term and results of two formalisms agree. Finally, we discuss
the role of supersymmetric and non-supersymmetric thresholds in the effective
low energy Lagrangian as well as the effects of explicit small mass parameters
(such as mu-term) on the superpartner spectrum.Comment: 19 pages; v3, published versio
New Models of Gauge Mediated Dynamical Supersymmetry Breaking
We propose a simple class of nonrenormalizable models of gauge mediated
dynamical supersymmetry breaking. The models do not have gauge singlet fields.
The Standard Model gauge group is embedded in the global symmetry of the SUSY
breaking sector. At the renormalizable level the models possess a set of
classical flat directions. Only one of those flat directions is unlifted by
quantum effects, and requires nonrenormalizable term to stabilize the potential
for the corresponding modulus. Large vacuum expectation value of this modulus
at the minimum of the potential generates mass terms for the messenger fields.
There are no light messengers, thus this class of models evades difficulties
encountered in earlier constructions using nonrenormalizable models.Comment: 8 pages, Late
The Problem of Dirac Gauginos and its Solutions
We examine the effective low-energy theory of the adjoint sector of Dirac
gaugino models and its UV completions, and identify the main source of tuning.
A holomorphic scalar adjoint mass square (the " term") is generated at the
same order (1-loop) as the Dirac gaugino mass (the " term"), leading to
the problematic relation , somewhat analogous to the
problem of gauge mediation. We identify the leading operators of
the low-energy effective theory contributing to the adjoint sector, and
evaluate them in various UV completions, confirming the existence of this
problem. We suggest a solution by introducing messenger mixing and tuning the
relevant parameters. We also present a novel dynamical model for Dirac gauginos
based on a strongly coupled SUSY QCD theory, where the additional adjoint
is identified with a confined meson, the U(1) with a baryon-number like
symmetry, and the messengers with the confined baryons. We find a SUSY breaking
vacuum with a non-vanishing D-term, which after tuning the messenger mixing
angles gives rise to a realistic gaugino and squark sector.Comment: 26 pages, 9 figures. v2: references added, typos fixed, minor
corrections to spectrum table. v3: fix to two-loop RGE of sfermion masses and
supertrace definition in the introductio
Moduli Decays and Gravitinos
One proposed solution of the moduli problem of string cosmology requires that
the moduli are quite heavy, their decays reheating the universe to temperatures
above the scale of nucleosynthesis. In many of these scenarios, the moduli are
approximately supersymmetric; it is then crucial that the decays to gravitinos
are helicity suppressed. In this paper, we discuss situations where these
decays are, and are not, suppressed. We also comment on a possible gravitino
problem from inflaton decay.Comment: 16 pages, version to appear in Physical Review
Deformations of the moduli space and superpotential flows in 3D SUSY QCD
We study the moduli space of three-dimensional SQCD with
gauge group and massless flavors. In the case of an
theory with a single massless flavor, we explicitly calculate the quantum
constraint and generalize the calculation to models with arbitrary
and flavors. In theories with flavors, we find that analogous
constraints exist in locally defined coordinate charts of the moduli space. The
existence of such constraints allows us to show that the Coulomb branch
superpotential generated by single monopole effects is equivalent to the
superpotential generated by multi-monopole contributions on the mixed
Higgs-Coulomb branch. As a check for our result, we implement the local
constraints as Lagrange multiplier terms in the superpotential and verify that
deformations of a theory by a large holomorphic mass term for the matter fields
results in a flow of the superpotential from the -flavor model to the
superpotential of an -flavor model.Comment: 18 pages; corrected typo
Twisted Sisters: KK Monopoles and their Zero Modes
We find the conditions for the existence of fermionic zero modes of the
fundamental representation in the background of a Kaluza-Klein (KK) monopole.
We show that while there is no zero mode without a real mass, a normalizable
zero mode appears once the real mass is sufficiently large. This provides an
elegant explanation for the known decoupling of KK monopole effects in
supersymmetric theories when a large real mass term is added. We also present
an application where the correct counting of KK zero modes plays an essential
role in understanding the non-perturbative effects determining the low-energy
dynamics.Comment: 5 pages. References adde
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