5,865 research outputs found
The New Flavor of Higgsed Gauge Mediation
Recent LHC bounds on squark masses combined with naturalness and flavor
considerations motivate non-trivial sfermion mass spectra in the supersymmetric
Standard Model. These can arise if supersymmetry breaking is communicated to
the visible sector via new extended gauge symmetries. Such extended symmetries
must be spontaneously broken, or confined, complicating the calculation of soft
masses. We develop a new formalism for calculating perturbative gauge-mediated
two-loop soft masses for gauge groups with arbitrary patterns of spontaneous
symmetry breaking, simplifying the framework of "Higgsed gauge mediation." The
resulting expressions can be applied to Abelian and non-Abelian gauge groups,
opening new avenues for supersymmetric model building. We present a number of
examples using our method, ranging from grand unified threshold corrections in
standard gauge mediation to soft masses in gauge extensions of the Higgs sector
that can raise the Higgs mass through non-decoupling D-terms. We also outline a
new mediation mechanism called "flavor mediation", where supersymmetry breaking
is communicated via a gauged subgroup of Standard Model flavor symmetries.
Flavor mediation can automatically generate suppressed masses for
third-generation squarks and implies a nearly exact U(2) symmetry in the first
two generations, yielding a "natural SUSY" spectrum without imposing ad hoc
global symmetries or giving preferential treatment to particular generations.Comment: 13 pages, 3 figures; v2: typos corrected, references adde
The Goldstini Variations
We study the 'goldstini' scenario of Cheung, Nomura, and Thaler, in which
multiple independent supersymmetry (SUSY) breaking sectors lead to multiple
would-be goldstinos, changing collider and cosmological phenomenology. In
supergravity, potentially large corrections to the previous prediction of twice
the gravitino mass for goldstini masses can arise when their scalar partners
are stabilized far from the origin. Considerations arising from the complexity
of realistic string compactifications indicate that many of the independent
SUSY-breaking sectors should be conformally sequestered or situated in warped
Randall-Sundrum-like throats, further changing the predicted goldstini masses.
If the sequestered hidden sector is a metastable SUSY-breaking sector of the
Intriligator-Seiberg-Shih (ISS) type then multiple goldstini can originate from
within a single sector, along with many supplementary 'modulini', all with
masses of order twice the gravitino mass. These fields can couple to the
Supersymmetric Standard Model (SSM) via the 'Goldstino Portal'. Collider
signatures involving SSM sparticle decays can provide strong evidence for
warped-or-conformally-sequestered sectors, and of the ISS mechanism of SUSY
breaking. Along with axions and photini, the Goldstino Portal gives another
potential window to the hidden sectors of string theory.Comment: 30 pages, 3 figures; v2 minor changes, references adde
The Vector-like Twin Higgs
We present a version of the twin Higgs mechanism with vector-like top
partners. In this setup all gauge anomalies automatically cancel, even without
twin leptons. The matter content of the most minimal twin sector is therefore
just two twin tops and one twin bottom. The LHC phenomenology, illustrated with
two example models, is dominated by twin glueball decays, possibly in
association with Higgs bosons. We further construct an explicit
four-dimensional UV completion and discuss a variety of UV completions relevant
for both vector-like and fraternal twin Higgs models.Comment: 39 pages; v2 published versio
AJAE Appendix: Nonlinear Dynamics and Structural Change in the U.S. Hog-Corn Ratio: A Time-Varying Star Approach
The material contained herein is supplementary to the article named in the title and published in the American Journal of Agricultural Economics, Volume 88, Number 1, February 2006.Agribusiness,
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