Tachyon-Free Non-Supersymmetric Strings on Orbifolds

TL;DR

This paper presents non-supersymmetric orbifold string models that are free of tachyons due to discrete torsion and Scherk-Schwarz phases, enabling stable gauge theories with chiral spectra but broken supersymmetry.

Contribution

It introduces tachyon-free non-supersymmetric orbifold constructions with stable D3-brane gauge theories, combining discrete torsion and Scherk-Schwarz phases to break supersymmetry.

Findings

Tachyons are projected out by discrete torsion.

Stable non-supersymmetric D3-brane gauge theories with chiral spectra.

Absence of tachyons supports non-supersymmetric model building.

Abstract

We discuss tachyon-free examples of (Type IIB on) non-compact non-supersymmetric orbifolds. Tachyons are projected out by discrete torsion between orbifold twists, while supersymmetry is broken by a Scherk-Schwarz phase (+1/-1 when acting on space-time bosons/fermions) accompanying some even order twists. The absence of tachyons is encouraging for constructing non-supersymmetric D3-brane gauge theories with stable infrared fixed points. The D3-brane gauge theories in our orbifold backgrounds have chiral N = 1 supersymmetric spectra, but non-supersymmetric interactions.