New F-theory lifts II: Permutation orientifolds and enhanced singularities

Understand

In this paper, a procedure is developed to construct compact F-theory fourfolds corresponding to perturbative IIB O7/O3 models on CICY threefolds with permutation involutions.

• The method is explained in generality, and then applied to specific examples where the involution permutes two Del Pezzo surfaces.
• The fourfold construction is successfully tested by comparing the D3 charges predicted by F-theory and IIB string theory.
• The constructed smooth fourfolds are then taken to the locus in moduli space where they have enhanced SU(5) singularities.