More on Non-supersymmetric Asymmetric Orbifolds with Vanishing Cosmological Constant

TL;DR

This paper investigates non-supersymmetric type II string vacua constructed via asymmetric orbifolds of tori, focusing on models with vanishing one-loop cosmological constant and analyzing their unitarity and stability.

Contribution

It introduces new classes of non-supersymmetric string vacua with asymmetric orbifolds, extending previous models by including different chiral reflections and excluding shift operators.

Findings

Models exhibit vanishing one-loop cosmological constant.

Certain orbifold modifications preserve unitarity and stability.

Common features of these non-supersymmetric vacua are identified.

Abstract

We explore various non-supersymmetric type II string vacua constructed based on asymmetric orbifolds of tori with vanishing cosmological constant at the one loop. The string vacua we present are modifications of the models studied in arXiv:1512.05155[hep-th], of which orbifold group is just generated by a single element. We especially focus on two types of modifications: (i) the orbifold twists include different types of chiral reflections not necessarily removing massless Rarita-Schwinger fields in the 4-dimensional space-time, (ii) the orbifold twists do not include the shift operator. We further discuss the unitarity and stability of constructed non-supersymmetric string vacua, with emphasizing the common features of them.