A note on non-flat points in the SU(5) × U(1) PQ F-theory model

摘要

A bstract Non-flat fibrations often appear in F-theory GUT models, and their interpretation is still somewhat mysterious. In this note we explore this issue in a model of particular phenomenological interest, the global SU(5) × U(1) Peccei-Quinn F-theory model. We present evidence that co-dimension three non-flat fibres give rise to higher order couplings in the effective four-dimensional superpotential — more specifically, in our example we find 10 5 5 5 couplings.