43 research outputs found
Supersymmetric Randall-Sundrum Scenario
We present the supersymmetric version of the minimal Randall-Sundrum model
with two opposite tension branes.Comment: Latex, 9 pages. Published versio
Supersymmetry Breaking in Warped Geometry
We examine the soft supersymmetry breaking parameters in supersymmetric
theories on a slice of AdS_5 which generate the hierarchical Yukawa couplings
by dynamically localizing the bulk matter fields in extra dimension. Such
models can be regarded as the AdS dual of the recently studied 4-dimensional
models which contain a supersymmetric CFT to generate the hierarchical Yukawa
couplings. In such models, if supersymmetry breaking is mediated by the bulk
radion superfield and/or some brane chiral superfields, potentially dangerous
flavor-violating soft parameters can be naturally suppressed, thereby avoiding
the SUSY flavor problem. We present some models of radion-dominated
supersymmetry breaking which yield a highly predictive form of soft parameters
in this framework.Comment: 17 pages, no figures, uses JHEP clas
Mediation of supersymmetry breaking in extra dimensions
We review the mechanisms of supersymmetry breaking mediation that occur in
sequestered models, where the visible and the hidden sectors are separated by
an extra dimension and communicate only via gravitational interactions. By
locality, soft breaking terms are forbidden at the classical level and reliably
computable within an effective field theory approach at the quantum level. We
present a self-contained discussion of these radiative gravitational effects
and the resulting pattern of soft masses, and give an overview of realistic
model building based on this set-up. We consider both flat and warped extra
dimensions, as well as the possibility that there be localized kinetic terms
for the gravitational fields.Comment: LaTex, 15 pages; brief review prepared for MPLA. v2: minor
correction
One loop gauge couplings in AdS5
We calculate the full 1-loop corrections to the low energy coupling of bulk
gauge boson in a slice of AdS5 which are induced by generic 5-dimensional
scalar, Dirac fermion, and vector fields with arbitrary Z_2 times Z_2' orbifold
boundary conditions. In supersymmetric limit, our results correctly reproduce
the results obtained by an independent method based on 4-dimensional effective
supergravity. This provides a nontrivial check of our results and assures the
regularization scheme-independence of the results.Comment: RevTeX, 22 pages, 2 figures, some typos corrected and notations
change
Interesting consequences of brane cosmology
We discuss cosmology in four dimensions within a context of brane-world
scenario.Such models can predict chaotic inflation with very low reheat
temperature depending on the brane tension. We notice that the gravitino
abundance is different in the brane-world cosmology and by tuning the brane
tension it is possible to get extremely low abundance. We also study
Affleck-Dine baryogenesis in our toy model.Comment: 5 pages, Trivial changes to match the published versio
The supermultiplet of boundary conditions in supergravity
Boundary conditions in supergravity on a manifold with boundary relate the
bulk gravitino to the boundary supercurrent, and the normal derivative of the
bulk metric to the boundary energy-momentum tensor. In the 3D N=1 setting, we
show that these boundary conditions can be stated in a manifestly
supersymmetric form. We identify the Extrinsic Curvature Tensor Multiplet, and
show that boundary conditions set it equal to (a conjugate of) the boundary
supercurrent multiplet. Extension of our results to higher-dimensional models
(including the Randall-Sundrum and Horava-Witten scenarios) is discussed.Comment: 22 pages. JHEP format; references added; published versio
Torsion Constraints in the Randall--Sundrum Scenario
Torsion appears due to fermions coupled to gravity and leads to the strongest
particle physics bounds on flat extra dimensions. In this work, we consider
torsion constraints in the case of a warped extra dimension with brane and bulk
fermions. From current data we obtain a 3-sigma bound on the TeV--brane mass
scale scale \Lambda_\pi > 2.2 (10) TeV for the AdS curvature k=1 (0.01) in
(reduced) Planck units. If Dirac or light sterile neutrinos reside on the
brane, the bound increases to 17 (78) TeV.Comment: typos corrected, matches the Phys. Rev. D versio
Universal contributions to scalar masses from five dimensional supergravity
We compute the effective Kahler potential for matter fields in warped
compactifications, starting from five dimensional gauged supergravity, as a
function of the matter fields localization. We show that truncation to zero
modes is inconsistent and the tree-level exchange of the massive gravitational
multiplet is needed for consistency of the four-dimensional theory. In addition
to the standard Kahler coming from dimensional reduction, we find the quartic
correction coming from integrating out the gravity multiplet. We apply our
result to the computation of scalar masses, by assuming that the SUSY breaking
field is a bulk hypermultiplet. In the limit of extreme opposite localization
of the matter and the spurion fields, we find zero scalar masses, consistent
with sequestering arguments. Surprisingly enough, for all the other cases the
scalar masses are tachyonic. This suggests the holographic interpretation that
a CFT sector always generates operators contributing in a tachyonic way to
scalar masses. Viability of warped su- persymmetric compactifications
necessarily asks then for additional contributions. We discuss the case of
additional bulk vector multiplets with mixed boundary conditions, which is a
partic- ularly simple and attractive way to generate large positive scalar
masses. We show that in this case successful fermion mass matrices implies
highly degenerate scalar masses for the first two generations of squarks and
sleptons.Comment: 23 pages. v2: References added, new section on effect of additional
bulk vector multiplets and phenomenolog
Flavour Violation in SUSY SU(5) GUT at Large tan beta
We study flavour violation in the minimal SUSY SU(5) GUT assuming all the
third generation Yukawa couplings to be due to the renormalizable physics above
GUT scale. At large as suggested by Yukawa unification in SU(5),
sizable flavour violation in the left (right) slepton (down squark) sector is
induced due to renormalization effects of down type Yukawa couplings between
GUT and Planck scales in addition to the flavour violation in the right slepton
sector. The new flavour physics contribution to mixing
is small but might be of phenomenological interest in the case of The sign of the latter contribution is the same as the sign of the
dominant chargino contribution, thus making the constraints on SUSY scale
coming from somewhat more restrictive. The most important
feature of the considered scenario is the large rate of lepton flavour
violation. Given the present experimental constraints, the and
conversion branching ratios are above the sensitivity of the planned
experiments unless the SUSY scale is pushed above one TeV.Comment: 22 pages, 7 figure
Cosmological Solutions on Compactified AdS_5 with a Thermal Bulk
This paper is an investigation of the effects of a thermal bulk fluid in
brane world models compactified on AdS_5. Our primary purpose is to study how
such a fluid changes the bulk dynamics and to compare these effects with those
generated by matter localized to the branes. We find an exact cosmological
solution for a thermally excited massless bulk field, as well as perturbative
solutions with matter on the brane and in the bulk. We then perturb around
these solutions to find solutions for a massive bulk mode in the limit where
the bulk mass (m_B) is small compared to the AdS curvature scale and T< m_B. We
find that without a stabilizing potential there are no physical solutions for a
thermal bulk fluid. We then include a stabilizing potential and calculate the
shift in the radion as well as the time dependence of the weak scale as a
function of the bulk mass. It is shown that, as opposed to a brane fluid, the
bulk fluid contribution to the bulk dynamics is controlled by the bulk mass.Comment: 20 pages LATE