Intersecting D-brane Models

TL;DR

This thesis explores intersecting D-brane models in string theory, demonstrating their potential to produce realistic low-energy physics, including the Standard Model spectrum, and analyzing related phenomenological features and geometric relationships.

Contribution

It constructs explicit intersecting D-brane configurations that yield the Standard Model spectrum and investigates their phenomenological and geometric properties.

Findings

Realistic Standard Model chiral spectrum obtained

Absence of open-string tachyons in configurations

Potential to lower string scale in these models

Abstract

This thesis is devoted to the study of a class of constructions based on Superstring Theory, baptized in the literature as Intersecting Brane Worlds. In particular we explore several issues regarding the proposal of Intersecting Brane Worlds as string-based models yielding semi-realistic low-energy physics. We find that they provide an interesting framework where, for instance, just the Standard Model chiral content and gauge group can be obtained. Although many of the results presented in this work are valid for more general constructions, we center on configurations of D-branes intersecting at angles. We construct several classes of such compactifications which may yield realistic D=4 physics. We build several explicit examples giving the Standard Model chiral spectrum, and then proceed to analyze some of the related phenomenology. We pay special attention to features such as the structure of U(1) global symmetries, the absence of open-string tachyons, the appearance of light extra matter and the possibility of lowering the string scale in such scenarios. Finally, we investigate the relationship between low-energy field theory quantities, such as FI-parameters and Yukawa couplings, with the geometrical objects underlying the string construction. We find that their description is closely related to calibration theory and to the construction of Fukaya's category.