Yukawa Structure from U(1) Fluxes in F-theory Grand Unification

Understand

In F-theory GUT constructions Yukawa couplings necessarily take place at the intersection of three matter curves.

• For generic geometric configurations this gives rise to problematic Yukawa couplings unable to reproduce the observed hierarchies.
• We point out that if the U(1)_{B-L}/U(1)_Y flux breaking the SO(10)/SU(5) GUT symmetry is allowed to go through pairs of matter curves with the same GUT representation, the quark/lepton content is redistributed in such a way that all quark and leptons are allowed to have hierarchical Yukawas.
• This reshuffling of fermions is quite unique and is particularly elegant for the case of three generations and SO(10).