11 research outputs found
A Formalism to Analyze the Spectrum of Brane World Scenarios
In this paper we develop a formalism to analyze the spectrum of small
perturbations about arbitrary solutions of Einstein, Yang-Mills and scalar
systems. We consider a general system of gravitational, gauge and scalar fields
in a dimensional space-time and give the bilinear action for the
fluctuations of the fields in the system around an arbitrary solution of the
classical field equations. We then consider warped geometries, popular in brane
world scenarios, and use the light cone gauge to separate the bilinear action
into a totally decoupled spin-two, -one and -zero fluctuations. We apply our
general scheme to several examples and discuss in particular localization of
abelian and non-abelian gauge fields of the standard model to branes generated
by scalar fields. We show in particular that the Nielsen-Olsen string solution
gives rise to a normalizable localized spin-1 field in any number of
dimensions.Comment: Latex, 31 pages. Final version appeared in Nucl. Phy
Fermion zero-modes on brane-worlds
We study localization of bulk fermions on a brane with inclusion of
Yang-Mills and scalar backgrounds in higher dimensions and give the conditions
under which localized chiral fermions can be obtained.Comment: Latex, 5 pages. A factor "2" mistake that propagated through a number
of equations is corrected. Conclusions unchange
On some new warped brane world solutions in higher dimensions
We present new solutions of higher dimensional Einstein's equations with a cosmological constant that localize gravity on branes which are transverse to Ricci-flat manifolds or to homogeneous spaces with topologically non-trivial solutions of gauge field equations. These solutions are relevant for the localization of chiral fermions on a brane. (C) 2000 Published by Elsevier Science B.V
QED from six-dimensional vortex and gauge anomalies
Starting from an anomaly-free Abelian Higgs model coupled to gravity in a
6-dimensional space-time we construct an effective four-dimensional theory of
charged fermions interacting with U(1) Abelian gauge field and gravity, both
localised near the core of a Nielsen-Olesen vortex configuration. We show that
an anomaly free theory in 6-dimensions can give rise to an anomalous theory in
D=4, which suggests a possibility of consistent regularisation of abelian
anomalous chiral gauge theories in four dimensions. We also show that the
spectrum of charged bulk fermions has a mass gap.Comment: Latex, 19 page
A New Anomaly-Free Gauged Supergravity in Six Dimensions
We present a new anomaly-free gauged N=1 supergravity model in six
dimensions. The gauge group is E_7xG_2xU(1)_R, with all hyperinos transforming
in the product representation {56,14). The theory admits monopole
compactifications to R^4xS^2, leading to D=4 effective theories with broken
supersymmetry and massless fermions.Comment: 9 pages, RevTeX
A Brane model with two asymptotic regions
Some brane models rely on a generalization of the Melvin magnetic universe
including a complex scalar field among the sources. We argue that the geometric
interpretation of Kip.S.Thorne of this geometry restricts the kind of potential
a complex scalar field can display to keep the same asymptotic behavior. While
a finite energy is not obtained for a Mexican hat potential in this
interpretation, this is the case for a potential displaying a broken phase and
an unbroken one. We use for technical simplicity and illustrative purposes an
ad hoc potential which however shares some features with those obtained in some
supergravity models. We construct a sixth dimensional cylindrically symmetric
solution which has two asymptotic regions: the Melvin-like metric on one side
and a flat space displaying a conical singularity on the other. The causal
structure of the configuration is discussed. Unfortunately, gravity is not
localized on the brane.Comment: 9 pages revtex, 4 figures,version to appear in PR