De Sitter Vacua from Heterotic M-Theory

TL;DR

This paper demonstrates how metastable de Sitter vacua can be achieved in heterotic M-theory through non-perturbative effects, leading to spontaneous supersymmetry breaking and realistic phenomenological features without fine-tuning.

Contribution

It introduces a mechanism for stabilizing moduli and obtaining de Sitter vacua in heterotic M-theory using non-perturbative effects without relying on exotic assumptions.

Findings

Stable de Sitter vacua are achieved without fine-tuning.

Charged scalar matter fields acquire non-zero VEVs and masses.

Realistic supersymmetry breaking scales are attainable.

Abstract

It is shown how metastable de Sitter vacua might arise from heterotic M-theory. The balancing of its two non-perturbative effects, open membrane instantons against gaugino condensation on the hidden boundary, which act with opposing forces on the interval length, is used to stabilize the orbifold modulus (dilaton) and other moduli. The non-perturbative effects break supersymmetry spontaneously through F-terms which leads to a positive vacuum energy density. In contrast to the situation for the weakly coupled heterotic string, the charged scalar matter fields receive non-vanishing vacuum expectation values and therefore masses in a phenomenologically relevant regime. It is important that in order to obtain these de Sitter vacua we are not relying on exotic effects or fine-tuning of parameters. Vacua with more realistic supersymmetry breaking scales and gravitino masses are obtained by breaking the hidden $E_8$ gauge group down to groups of smaller rank. Also small values for the open membrane instanton Pfaffian are favored in this respect. Finally we outline how the incorporation of additional flux superpotentials can be used to stabilize the remaining moduli.