Discrete R-symmetries and Anomaly Universality in Heterotic Orbifolds

TL;DR

This paper derives discrete R-symmetries in heterotic orbifold models from geometric symmetries, providing a more general framework that reveals differences from previous explicit calculations and discusses anomaly implications.

Contribution

It introduces a geometric approach to determine R-charges in heterotic orbifolds, extending beyond prior explicit correlation function methods and including models with Wilson lines.

Findings

Derived R-charges differ from previous explicit results in certain models.

Established a geometric method for R-symmetry determination.

Analyzed anomalies associated with these R-symmetries.

Abstract

We study discrete R-symmetries, which appear in 4D low energy effective field theory derived from hetetoric orbifold models. We derive the R-symmetries directly from geometrical symmetries of orbifolds. In particular, we obtain the corresponding R-charges by requiring that the couplings be invariant under these symmetries. This allows for a more general treatment than the explicit computations of correlation functions made previously by the authors, including models with discrete Wilson lines, and orbifold symmetries beyond plane-by-plane rotational invariance. Surprisingly, for the cases covered by earlier explicit computations, the R-charges differ from the previous result. We study the anomalies associated with these R-symmetries, and comment on the results.