On Moduli Stabilisation and de Sitter Vacua in MSSM Heterotic Orbifolds

TL;DR

This paper investigates moduli stabilization in heterotic orbifold compactifications with MSSM spectra, combining various effects to find de Sitter vacua, which are currently unstable.

Contribution

It provides explicit calculations of the effective action including perturbative and non-perturbative effects, leading to new insights into moduli stabilization and de Sitter vacua.

Findings

All bulk moduli can be stabilized with combined effects.

Several de Sitter solutions are found, but they are unstable.

Concrete models reveal properties often missed in generic analyses.

Abstract

We study the problem of moduli stabilisation in explicit heterotic orbifold compactifications, whose spectra contain the MSSM plus some vector-like exotics that can be decoupled. Considering all the bulk moduli, we obtain the 4D low energy effective action for the compactification, which has contributions from various, computable, perturbative and non-perturbative effects. Hidden sector gaugino condensation and string worldsheet instantons result in a combination of racetrack, KKLT and cusp-form contributions to the superpotential, which lift all the bulk moduli directions. We point out the properties observed in our concrete models, which tend to be missed when only "generic" features of a model are assumed. We search for interesting vacua and find several de Sitter solutions, but -- so far -- they all turn out to be unstable.