1,885 research outputs found

### Shape of Deconstruction

We construct a six-dimensional Maxwell theory using a latticized extra space,
the continuum limit of which is a shifted torus recently discussed by Dienes.
This toy model exhibits the correspondence between continuum theory and
discrete theory, and give a geometrical insight to theory-space model building.Comment: 10 pages, 2 figures, RevTeX4. a citation adde

### Discretizing Gravity in Warped Spacetime

We investigate the discretized version of the compact Randall-Sundrum model.
By studying the mass eigenstates of the lattice theory, we demonstrate that for
warped space, unlike for flat space, the strong coupling scale does not depend
on the IR scale and lattice size. However, strong coupling does prevent us from
taking the continuum limit of the lattice theory. Nonetheless, the lattice
theory works in the manifestly holographic regime and successfully reproduces
the most significant features of the warped theory. It is even in some respects
better than the KK theory, which must be carefully regulated to obtain the
correct physical results. Because it is easier to construct lattice theories
than to find exact solutions to GR, we expect lattice gravity to be a useful
tool for exploring field theory in curved space.Comment: 17 pages, 4 figures; references adde

### The Minimal Moose for a Little Higgs

Recently a new class of theories of electroweak symmetry breaking have been
constructed. These models, based on deconstruction and the physics of theory
space, provide the first alternative to weak-scale supersymmetry with naturally
light Higgs fields and perturbative new physics at the TeV scale. The Higgs is
light because it is a pseudo-Goldstone boson, and the quadratically divergent
contributions to the Higgs mass are cancelled by new TeV scale ``partners'' of
the {\em same} statistics. In this paper we present the minimal theory space
model of electroweak symmetry breaking, with two sites and four link fields,
and the minimal set of fermions. There are very few parameters and degrees of
freedom beyond the Standard Model. Below a TeV, we have the Standard Model with
two light Higgs doublets, and an additional complex scalar weak triplet and
singlet. At the TeV scale, the new particles that cancel the 1-loop quadratic
divergences in the Higgs mass are revealed. The entire Higgs potential needed
for electroweak symmetry breaking--the quartic couplings as well as the
familiar negative mass squared--can be generated by the top Yukawa coupling,
providing a novel link between the physics of flavor and electroweak symmetry
breaking.Comment: 15 pages. References added. Included clarifying comments on the
origin of quartic couplings, and on power-counting. More elegant model for
generating Higgs potential from top Yukawa coupling presente

### On the one-loop Kahler potential in five-dimensional brane-world supergravity

We present an on-shell formulation of 5d gauged supergravity coupled to
chiral matter multiplets localized at the orbifold fixed points. The brane
action is constructed via the Noether method. In such set-up we compute
one-loop corrections to the Kahler potential of the effective 4d supergravity
and compare the result with previous computations based on the off-shell
formalism. The results agree at lowest order in brane sources, however at
higher order there are differences. We explain this discrepancy by an ambiguity
in resolving singularities associated with the presence of infinitely thin
branes.Comment: 20 page

### A "Littlest Higgs" Model with Custodial SU(2) Symmetry

In this note, a ``littlest higgs'' model is presented which has an
approximate custodial SU(2) symmetry. The model is based on the coset space
$SO(9)/(SO(5)\times SO(4))$. The light pseudo-goldstone bosons of the theory
include a {\it single} higgs doublet below a TeV and a set of three $SU(2)_W$
triplets and an electroweak singlet in the TeV range. All of these scalars
obtain approximately custodial SU(2) preserving vacuum expectation values. This
model addresses a defect in the earlier $SO(5)\times SU(2)\times U(1)$ moose
model, with the only extra complication being an extended top sector. Some of
the precision electroweak observables are computed and do not deviate
appreciably from Standard Model predictions. In an S-T oblique analysis, the
dominant non-Standard Model contributions are the extended top sector and higgs
doublet contributions. In conclusion, a wide range of higgs masses is allowed
in a large region of parameter space consistent with naturalness, where large
higgs masses requires some mild custodial SU(2) violation from the extended top
sector.Comment: 22 pages + 8 figures; JHEP style, added references and extra
discussion on size of T contributions, as well as some other minor
clarifications. Version to appear in JHE

### D-type supersymmetry breaking and brane-to-brane gravity mediation

We revisit the issue of gravitational contributions to soft masses in
five-dimensional sequestered models. We point out that, unlike for the case of
F-type supersymmetry breaking, for D-type breaking these effects generically
give positive soft masses squared for the sfermions. This drastically improves
model building. We discuss the phenomenological implications of our result.Comment: 16 pages. Typos corrected, minor clarifications. To be published in
Phys. Lett.

### The Simplest Little Higgs

We show that the SU(3) little Higgs model has a region of parameter space in
which electroweak symmetry breaking is natural and in which corrections to
precision electroweak observables are sufficiently small. The model is anomaly
free, generates a Higgs mass near 150 GeV, and predicts new gauge bosons and
fermions at 1 TeV.Comment: 13 pages + appendix, typos corrected, version to appear in JHE

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