Chiral supergravities
Author(s)
Pugh, Tom
Type
Thesis
Abstract
A large class of dimensional reductions of interesting ultraviolet theories do not give rise
to chiral effective theories. As the Standard Model is a chiral theory this represents
an obstacle for many phenomenological constructions. The aim of this thesis will be to
present a series of constructions and reductions in which chiral theories are produced,
with the intention that these may be used as illustrative examples of situations in which
the problems associated with chirality in dimensional reductions can be avoided.
We will consider the way in which a chiral theory may be generated, in the reduction
of an odd-dimensional theory, by focusing on a reduction on the orbifold S1/Z2 . In doing
this we will adopt the picture in which the orbifold is viewed as being a manifold with
boundaries. Many of the features of these reductions will be demonstrated by analysing
seven-dimensional supergravity with six-dimensional boundaries. A critical part of this
discussion will center around the cancellation of anomalies which can form on these boundaries.
This cancellation will be arranged by coupling certain boundary-localised matter.
We will then consider the constraints that arise in allowing a consistent set of boundary-localised
matter to be coupled to a given bulk system. We will illustrate this by analysing
three-dimensional supergravity on a manifold with two-dimensional boundaries. We will
then demonstrate how these constructions may be carried out in an alternative formalism,
in which the details become more transparent.
We will also explore reductions in which chirality can be preserved, by presenting the
reduction of six-dimensional gauged supergravity on a sphere and monopole background.
We will show that in this case a bifurcation occurs and a consistent reduction to either a
chiral or a non-chiral theory may be carried out.
to chiral effective theories. As the Standard Model is a chiral theory this represents
an obstacle for many phenomenological constructions. The aim of this thesis will be to
present a series of constructions and reductions in which chiral theories are produced,
with the intention that these may be used as illustrative examples of situations in which
the problems associated with chirality in dimensional reductions can be avoided.
We will consider the way in which a chiral theory may be generated, in the reduction
of an odd-dimensional theory, by focusing on a reduction on the orbifold S1/Z2 . In doing
this we will adopt the picture in which the orbifold is viewed as being a manifold with
boundaries. Many of the features of these reductions will be demonstrated by analysing
seven-dimensional supergravity with six-dimensional boundaries. A critical part of this
discussion will center around the cancellation of anomalies which can form on these boundaries.
This cancellation will be arranged by coupling certain boundary-localised matter.
We will then consider the constraints that arise in allowing a consistent set of boundary-localised
matter to be coupled to a given bulk system. We will illustrate this by analysing
three-dimensional supergravity on a manifold with two-dimensional boundaries. We will
then demonstrate how these constructions may be carried out in an alternative formalism,
in which the details become more transparent.
We will also explore reductions in which chirality can be preserved, by presenting the
reduction of six-dimensional gauged supergravity on a sphere and monopole background.
We will show that in this case a bifurcation occurs and a consistent reduction to either a
chiral or a non-chiral theory may be carried out.
Date Issued
2012-03
Date Awarded
2012-10
Copyright Statement
Attribution NoDerivatives 4.0 International Licence (CC BY-ND)
Advisor
Stelle, Kellogg
Sponsor
Science and Technology Facilities Council (Great Britain)
Publisher Department
Physics
Publisher Institution
Imperial College London
Qualification Level
Doctoral
Qualification Name
Doctor of Philosophy (PhD)