Physics beyond the standard model: moduli stabilisation and neutrino physics


Boudjemaa, Salima (2009) Physics beyond the standard model: moduli stabilisation and neutrino physics. University of Southampton, School of Physics and Astronomy, Doctoral Thesis , 163pp.

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Description/Abstract

We look at models of neutrino mass and mixing which represent an important aspect
of physics beyond the Standard Model (SM). We derive approximate analytic formulae for the neutrino mixing angles in general SD involving NLO and NNLO
corrections. These expressions, which are given in terms of input see-saw parameters, provide a useful guide for unified model building. We then evaluate these
formulae in the cases of CSD and PCSD for two numerical GUT inspired models
in order to measure the effect of NLO and NNLO corrections. In addition to this,
we analyse the effects of charged lepton corrections and Renormalisation Group
(RG) running on neutrino mixing angles and various sum rules, in models where
tri-bimaximal mixing is exactly achieved at high energy scale. We find the RG
corrections to neutrino sum rules to be typically small for the case of hierarchical
neutrinos.

Another aspect of physics beyond the Standard Model concerns the search for viable
four dimensional string models. We look at moduli stabilisation in the framework
of four dimensional models arising from heterotic and type IIA string theories.
The superpotentials in these models involve
ux and non-perturbative terms. We
consider a set of conditions which lead to moduli solutions for Minkowski minima of
the scalar potential. Following this procedure, we correct models presented in the literature and uplift the
at directions. We also study inflation in the framework of
these models. We find that it is successfully achieved along the axionic directions of the moduli fields for values of the initial conditions within substantial regions
of parameter space. A very interesting structure of the potential is obtained when
considering the evolution of two axionic directions in one of the models in the presence
of a gaugino condensate term. This structure, which involves the existence of
multiple local minima surrounding the global one, represents a perfect background
for realising in
ation.

Item Type: Thesis (Doctoral)
Subjects: Q Science > QC Physics
Divisions: University Structure - Pre August 2011 > School of Physics and Astronomy
ePrint ID: 161213
Date Deposited: 30 Jul 2010 15:56
Last Modified: 27 Mar 2014 19:16
URI: http://eprints.soton.ac.uk/id/eprint/161213

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