Calabi-Yau compactifications of non-supersymmetric heterotic string theory

TL;DR

This paper explores Calabi-Yau compactifications of all three ten-dimensional heterotic string theories, especially the non-supersymmetric SO(16)xSO(16) theory, to construct SM-like models and analyze their spectra and anomaly structures.

Contribution

It demonstrates the construction of non-supersymmetric Calabi-Yau models with Standard Model features and analyzes their spectra and anomaly cancellation conditions.

Findings

Non-supersymmetric SO(16)xSO(16) models exhibit similarities to supersymmetric theories.

SM-like models can be obtained with specific Wilson lines.

Anomaly factorization limits solutions to at most one brane in certain configurations.

Abstract

Phenomenological explorations of heterotic strings have conventionally focused primarily on the E8xE8 theory. We consider smooth compactifications of all three ten-dimensional heterotic theories to exhibit the many similarities between the non-supersymmetric SO(16)xSO(16) theory and the related supersymmetric E8xE8 and SO(32) theories. In particular, we exploit these similarities to determine the bosonic and fermionic spectra of Calabi-Yau compactifications with line bundles of the non-supersymmetric string. We use elements of four-dimensional supersymmetric effective field theory to characterize the non-supersymmetric action at leading order and determine the Green-Schwarz induced axion-couplings. Using these methods we construct a non-supersymmetric Standard Model(SM)-like theory. In addition, we show that it is possible to obtain SM-like models from the standard embedding using at least an order four Wilson line. Finally, we make a proposal of the states that live on five branes in the SO(16)xSO(16) theory and find under certain assumptions the surprising result that anomaly factorization only admits at most a single brane solution.