Heterotic GUT and Standard Model Vacua from simply connected Calabi-Yau Manifolds

TL;DR

This paper constructs GUT and Standard Model vacua from simply connected Calabi-Yau manifolds in heterotic string theory, demonstrating realistic models with desirable features like proton stability and altered gauge coupling relations.

Contribution

It introduces a method to realize GUT and Standard Model vacua on simply connected Calabi-Yau manifolds with specific vector bundles and five-branes, including concrete three-generation models.

Findings

Realization of GUT models with U(1) factors on simply connected Calabi-Yau manifolds.

Models exhibit flipped SU(5) features such as doublet-triplet splitting.

Tree level gauge coupling relations differ from conventional GUT models.

Abstract

We consider four-dimensional supersymmetric compactifications of the E8 x E8 heterotic string on Calabi-Yau manifolds endowed with vector bundles with structure group SU(N) x U(1) and five-branes. After evaluating the Green-Schwarz mechanism and deriving the generalized Donaldson-Uhlenbeck-Yau condition including the five-brane moduli, we show that this construction can give rise to GUT models containing U(1) factors like flipped SU(5) or directly the Standard Model even on simply connected Calabi-Yau manifolds. Concrete realizations of three-generation models on elliptically fibered Calabi-Yau manifolds are presented. They exhibit the most attractive features of flipped SU(5) models such as doublet-triplet splitting and proton stability. In contrast to conventional GUT string models, the tree level relations among the Standard Model gauge couplings at the GUT scale are changed.