Light $U(1)$s in heterotic string models

Abstract

We present a novel string-derived $U(1)$ combination that satisfies necessary properties to survive to low scales. We discuss previous attempts at acquiring such an abelian gauge symmetry from two different string embeddings and the pitfalls associated with them. Finally, we give an example of how a satisfactory model may be constructed within our framework.

Comments: Contribution to the proceedings of the DISCRETE 2014 Colloquium at King's College, London