The Standard Model from Stable Intersecting Brane World Orbifolds

TL;DR

This paper investigates the stability of non-supersymmetric intersecting brane models on tori, showing how certain orbifold constructions can avoid instabilities and naturally produce a Standard Model-like spectrum with GUT-scale string physics.

Contribution

It constructs explicit orbifold models that stabilize complex structure moduli and realize a three-generation Standard Model from an SU(5) GUT framework, highlighting phenomenological implications.

Findings

Certain orbifold models lack dynamical instabilities.

The string scale must be at least GUT scale for phenomenological viability.

Some Yukawa couplings are absent, affecting the Higgs mechanism.

Abstract

We analyze the perturbative stability of non-supersymmetric intersecting brane world models on tori. Besides the dilaton tadpole, a dynamical instability in the complex structure moduli space occurs at string disc level, which drives the background geometry to a degenerate limit. We show that in certain orbifold models this latter instability is absent as the relevant moduli are frozen. We construct explicit examples of such orbifold intersecting brane world models and discuss the phenomenological implications of a three generation Standard Model which descends naturally from an SU(5) GUT theory. It turns out that various phenomenological issues require the string scale to be at least of the order of the GUT scale. As a major difference compared to the Standard Model, some of the Yukawa couplings are excluded so that the standard electroweak Higgs mechanism with a fundamental Higgs scalar is not realized in this set-up.