Toric K3-Fibred Calabi-Yau Manifolds with del Pezzo Divisors for String Compactifications

TL;DR

This paper explores explicit toric K3-fibred Calabi-Yau three-folds with del Pezzo divisors, crucial for string compactifications, moduli stabilization, and model building in string phenomenology.

Contribution

It identifies and analyzes 158 examples of K3-fibred Calabi-Yau manifolds with specific del Pezzo divisors suitable for string model building.

Findings

158 examples of K3-fibred Calabi-Yau manifolds with del Pezzo divisors

Distinction between diagonal and non-diagonal del Pezzo divisors in simplicial and non-simplicial polytopes

Explicit topological analysis of selected examples for string compactification applications

Abstract

We analyse several explicit toric examples of compact K3-fibred Calabi-Yau three-folds which can be used for the study of string dualities and are crucial ingredients for the construction of LARGE Volume type IIB vacua with promising applications to cosmology and particle phenomenology. In order to build a phenomenologically viable model, on top of the two moduli corresponding to the base and the K3 fibre, we demand also the existence of two additional rigid divisors: the first supporting the non-perturbative effects needed to achieve moduli stabilisation, and the second allowing the presence of chiral matter on wrapped D-branes. We clarify the topology of these rigid divisors by discussing the interplay between a diagonal structure of the Calabi-Yau volume and D-terms. Del Pezzo divisors appearing in the volume form in a completely diagonal way are natural candidates for supporting non-perturbative effects and for quiver constructions, while `non-diagonal' del Pezzo and rigid but not del Pezzo divisors are particularly interesting for model building in the geometric regime. Searching through the existing list of four dimensional reflexive lattice polytopes, we find 158 examples admitting a Calabi-Yau hypersurface which is a K3 fibration with four K\"ahler moduli where at least one of them is a `diagonal' del Pezzo. We work out explicitly the topological details of a few examples showing how, in the case of simplicial polytopes, all the del Pezzo divisors are `diagonal', while `non-diagonal' ones appear only in the case of non-simplicial polytopes. A companion paper will use these results in the study of moduli stabilisation for globally consistent explicit Calabi-Yau compactifications with the local presence of chirality.