9,455 research outputs found
Inflation and Gauge Hierarchy in Randall-Sundrum Compactification
We obtain the general inflationary solutions for the slab of five-dimensional
AdS spacetime where the fifth dimension is an orbifold and two
three-branes reside at its boundaries, of which the Randall-Sundrum model
corresponds to the static limit. The investigation of the general solutions and
their static limit reveals that the RS model recasts both the cosmological
constant problem and the gauge hierarchy problem into the balancing problem of
the bulk and the brane cosmological constants.Comment: 9 pages, revtex, minor changes and more references adde
Quark and Lepton Masses in 5D SO(10)
We construct a five dimensional supersymmetric SO(10)D grand
unified model with an orbifold as the extra
dimension. The orbifold breaks half of the supersymmetry and breaks the SO(10)
gauge symmetry down to . The Higgs mechanism is used to break the remaining gauge symmetry
the rest of the way to the Standard Model. We place matter fields variously in
the bulk and on the orbifold fixed points and the resulting massless fields are
mixtures between these brane and bulk fields. A chiral adjoint field in the
bulk gets a U(1) vacuum expectation value, resulting in an -dependent
localization of the bulk matter fields and the Standard Model Higgs field. This
Higgs field localization allows us to simultaneously explain the hierarchies
and . The model uses 11 parameters to fit the 13
independent low energy observables of the quark and charged lepton Yukawa
matrices. The model predicts the values of two quark mass combinations,
\f{m_u}{m_c} and , each of which are predicted to be
approximately above their experimental values. The remaining
observables are successfully fit at the 5% level.Comment: 52 pages, published version, includes more discussion of 6D version
of mode
Core-Level X-Ray Photoemission Satellites in Ruthenates: A New Mechanism Revealing the Mott Transition
Ru 3d core-level x-ray photoemission spectra of various ruthenates are
examined. They show in general two-peak structures, which can be assigned as
the screened and unscreened peaks. The screened peak is absent in a Mott
insulator, but develops into a main peak in the metallic regime. This spectral
behavior is well explained by the dynamical mean-field theory calculation for
the single-band Hubbard model with on-site core-hole potential using the exact
diagonalization method. The new mechanism of the core-level photoemission
satellite can be utilized to reveal the Mott transition phenomenon in various
strongly correlated electron systems, especially in nano-scale devices and
phase-separated materials.Comment: 4 pages, 5 figures, submitted to PR
Gauge coupling renormalization in orbifold field theories
We investigate the gauge coupling renormalization in orbifold field theories
preserving 4-dimensional N=1 supersymmetry in the framework of 4-dimensional
effective supergravity. As a concrete example, we consider the 5-dimensional
Super-Yang-Mills theory on a slice of AdS_5. In our approach, one-loop gauge
couplings can be determined by the loop-induced axion couplings and the tree
level properties of 4-dimensional effective supergravity which are much easier
to be computed.Comment: 18 pages, JHEP style; 1-loop corrections to gauge kinetic functions
are fully computed, references are adde
Neutrinos in 5D SO(10) Unification
We study neutrino physics in a 5D supersymmetric SO(10) GUT. We analyze
several different choices for realizing the See-Saw mechanism. We find that the
"natural" scale for the Majorana mass of right-handed neutrinos depends
critically on whether the right-handed neutrinos are located in the bulk or
localized on a brane. In the former case, the effective Majorana mass is
"naturally" of order the compactification scale, about 10^{14} GeV. Note, this
is the value necessary for obtaining a light tau neutrino mass approximately
10^{-2} eV which, within the context of hierarchical neutrino masses, is the
right order of magnitude to explain atmospheric neutrino oscillations. On the
other-hand when the right-handed neutrino is localized on the brane, the
effective Majorana mass is typically larger than the compactification scale.
Nevertheless with small parameters of order 1/10 - 1/30, an effective Majorana
mass of order 10^{14} GeV can be accommodated. We also discuss the constraints
on model building resulting from the different scenarios for locating the
right-handed neutrinos.Comment: 24 page
Running of Gauge Couplings in AdS5 via Deconstruction
Running of gauge couplings on a slice of AdS5 is examined using the
deconstruction set-up. Logarithmic running instead of (linear) power law is
justified when the cutoff is lower than the curvature scale. Most of
interesting features in warped gauge theory including the localization of
Kaluza-Klein modes, the widening of higher Kaluza-Klein spectrum spacing are
well captured within the framework of the deconstruction.Comment: 20 pages, 3 figures, revtex, refereces added and typos corrected; the
version published in JHE
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