630 research outputs found
Domain Wall World(s)
Gravitational properties of domain walls in fundamental theory and their
implications for the trapping of gravity are reviewed. In particular, the
difficulties to embed gravity trapping configurations within gauged
supergravity is reviewed and the status of the domain walls obtained via the
breathing mode of sphere reduced Type IIB supergravity is presented.Comment: 11 pages, Based on talk given at Strings 2000 Minor corrections,
references adde
Kaluza-Klein Consistency, Killing Vectors, and Kahler Spaces
We make a detailed investigation of all spaces Q_{n_1... n_N}^{q_1... q_N} of
the form of U(1) bundles over arbitrary products \prod_i CP^{n_i} of complex
projective spaces, with arbitrary winding numbers q_i over each factor in the
base. Special cases, including Q_{11}^{11} (sometimes known as T^{11}),
Q_{111}^{111} and Q_{21}^{32}, are relevant for compactifications of type IIB
and D=11 supergravity. Remarkable ``conspiracies'' allow consistent
Kaluza-Klein S^5, S^4 and S^7 sphere reductions of these theories that retain
all the Yang-Mills fields of the isometry group in a massless truncation. We
prove that such conspiracies do not occur for the reductions on the Q_{n_1...
n_N}^{q_1... q_N} spaces, and that it is inconsistent to make a massless
truncation in which the non-abelian SU(n_i+1) factors in their isometry groups
are retained. In the course of proving this we derive many properties of the
spaces Q_{n_1... n_N}^{q_1... q_N} of more general utility. In particular, we
show that they always admit Einstein metrics, and that the spaces where
q_i=(n_i+1)/\ell all admit two Killing spinors. We also obtain an iterative
construction for real metrics on CP^n, and construct the Killing vectors on
Q_{n_1... n_N}^{q_1... q_N} in terms of scalar eigenfunctions on CP^{n_i}. We
derive bounds that allow us to prove that certain Killing-vector identities on
spheres, necessary for consistent Kaluza-Klein reductions, are never satisfied
on Q_{n_1... n_N}^{q_1... q_N}.Comment: Latex, 43 pages, references added and typos correcte
Supersymmetric Intersecting D6-Branes and Fluxes in Massive Type IIA String Theory
We study N=1 supersymmetric four-dimensional solutions of massive Type IIA supergravity with intersecting D6-branes in the presence NS-NS three-form fluxes. We derive N=1 supersymmetry conditions for the D6-brane and flux configurations in an internal manifold X6 and derive the intrinsic torsion (or SU(3)-structure) related to the fluxes. In the absence of fluxes, N=1 supersymmetry implies that D6-branes wrap supersymmetric three-cycles of X6 that intersect at angles of SU(3) rotations and the geometry is deformed by SU(3)-structures. The presence of fluxes breaks the SU(3) structures to SU(2) and the D6-branes intersect at angles of SU(2) rotations; non-zero mass parameter corresponds to D8-branes which are orthogonal to the common cycle of all D6-branes. The anomaly inflow indicates that the gauge theory on intersecting (massive) D6-branes is not chiral
Z' Physics and Supersymmetry
We review the status of heavy neutral gauge bosons, Z', with emphasis on
constraints that arise in supersymmetric models, especially those motivated
from superstring compactifications. We first summarize the current
phenomenological constraints and the prospects for Z' detection and diagnostics
at the LHC and NLC. After elaborating on the status and (lack of) predictive
power for general models with an additional Z', we concentrate on motivations
and successes for Z' physics in supersymmetric theories in general and in a
class of superstring models in particular. We review phenomenologically viable
scenarios with the Z' mass in the electroweak or in the intermediate scale
region.Comment: 30 pages. To appear in Perspectives in Supersymmetry, World
Scientific, ed. G. L. Kan
Non-extreme black holes from non-extreme intersecting M-branes
We present non-extreme generalisations of intersecting p-brane solutions of
eleven-dimensional supergravity which upon toroidal compactification reduce to
non-extreme static black holes in dimensions D=4, D=5 and 5<D<10, parameterized
by four, three and two charges, respectively. The D=4 black holes are obtained
either from non-extreme configuration of three intersecting five-branes with a
boost along the common string or from non-extreme intersecting system of two
two-branes and two five-branes. The D=5 black holes arise from three
intersecting two-branes or from a system of intersecting two-brane and
five-brane with a boost along the common string. Five-brane and two-brane with
a boost along one direction reduce to black holes in D=6 and D=9, respectively,
while D=7 black hole can be interpreted in terms of non-extreme configuration
of two intersecting two-branes. We discuss the expressions for the
corresponding masses and entropies.Comment: 19 pages, latex (misprints corrected; remarks added in section 6
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