High U(1) charges in type IIB models and their F-theory lift

Understand

We construct models with U(1) gauge group and matter with charges up to 6, in the context of type IIB compactifications.

• We show explicitly that models with charges up to 4 can be derived from corresponding models in F-theory by applying the Sen weak coupling limit.
• We derive which type IIB models should be the limit of charge 5 and 6 F-theory models.
• Explicit six dimensional type IIB models with maximal charge 5 and 6 are constructed on an algebraic K3 surface that is the double cover of $\mathbb{CP}^2$.