Comments on A,B,C Chains of Heterotic and Type II Vacua

TL;DR

This paper constructs new Calabi-Yau manifolds as hypersurfaces in toric varieties, expanding the landscape of F-theory vacua dual to heterotic string compactifications with non-semisimple gauge backgrounds, using extremal transitions.

Contribution

It extends previous work by generating many new examples of Calabi-Yau manifolds with enhanced gauge symmetries through conifold extremal transitions from known models.

Findings

Constructed numerous new Calabi-Yau examples with enhanced gauge symmetries.

Demonstrated that these vacua can be obtained via extremal transitions from known models.

Extended the class of F-theory vacua dual to heterotic string compactifications.

Abstract

We construct, as hypersurfaces in toric varieties, Calabi-Yau manifolds corresponding to F-theory vacua dual to E8*E8 heterotic strings compactified to six dimensions on K3 surfaces with non-semisimple gauge backgrounds. These vacua were studied in the recent work of Aldazabal, Font, Ibanez and Uranga. We extend their results by constructing many more examples, corresponding to enhanced gauge symmetries, by noting that they can be obtained from previously known Calabi-Yau manifolds corresponding to K3 compactification of heterotic strings with simple gauge backgrounds by means of extremal transitions of the conifold type.