Type I string phenomenology and extra dimensional models
Type I string phenomenology and extra dimensional models
We study the phenomenological consequences of type I string constructions and higher-dimensional effective field theories involving Dirichlet-branes with the aim of forging a connection between the underlying string theory and observable low-energy physics. First, we propose a mechanism for mediating supersymmetry (SUSY) breaking in type I string constructions with intersecting D-branes. We consider an explicit example with a Pati-Salam-like gauge symmetry, where only the third family and Higgs scalars acquire large soft masses. We compare the low-energy sparticle spectrum with gaugino mediation and no-scale supergravity models. Second, we use a model-independent parameterisation to study the localised twisted moduli contributions to supersymmetry breaking in the effective low-energy supergravity description of type I models. We derive general expressions for soft masses and trilinears in terms of Goldstino angles that control the relative contributions to supersymmetry breaking from the closed string sector. Finally, we study electroweak symmetry breaking in a five-dimensional effective field theory were supersymmetry is broken on a spatially-separated brane. We evaluate the dominant Kaluza-Klein (KK) contributions to the I-loop effective potential, and calculate the physical Higgs mass spectrum as a function of tan 3 and the compactification of scale MC.
University of Southampton
Rayner, David A. J
43d227f9-ed4d-4eae-80b3-12f1ce12e559
2002
Rayner, David A. J
43d227f9-ed4d-4eae-80b3-12f1ce12e559
Rayner, David A. J
(2002)
Type I string phenomenology and extra dimensional models.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
We study the phenomenological consequences of type I string constructions and higher-dimensional effective field theories involving Dirichlet-branes with the aim of forging a connection between the underlying string theory and observable low-energy physics. First, we propose a mechanism for mediating supersymmetry (SUSY) breaking in type I string constructions with intersecting D-branes. We consider an explicit example with a Pati-Salam-like gauge symmetry, where only the third family and Higgs scalars acquire large soft masses. We compare the low-energy sparticle spectrum with gaugino mediation and no-scale supergravity models. Second, we use a model-independent parameterisation to study the localised twisted moduli contributions to supersymmetry breaking in the effective low-energy supergravity description of type I models. We derive general expressions for soft masses and trilinears in terms of Goldstino angles that control the relative contributions to supersymmetry breaking from the closed string sector. Finally, we study electroweak symmetry breaking in a five-dimensional effective field theory were supersymmetry is broken on a spatially-separated brane. We evaluate the dominant Kaluza-Klein (KK) contributions to the I-loop effective potential, and calculate the physical Higgs mass spectrum as a function of tan 3 and the compactification of scale MC.
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Published date: 2002
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Local EPrints ID: 464703
URI: http://eprints.soton.ac.uk/id/eprint/464703
PURE UUID: b110d2f1-9132-48ae-826b-87b16372b48f
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Date deposited: 04 Jul 2022 23:57
Last modified: 16 Mar 2024 19:42
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Author:
David A. J Rayner
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