Large U(1) charges from flux breaking in 4D F-theory models

Abstract

We study the massless charged spectrum of U(1) gauge fields in F-theory that arise from flux breaking of a nonabelian group. The U(1) charges that arise in this way can be very large. In particular, using vertical flux breaking, we construct an explicit 4D F-theory model with a U(1) decoupled from other gauge sectors, in which the massless/light fields have charges as large as 657. This result greatly exceeds prior results in the literature. We argue heuristically that this result may provide an upper bound on charges for light fields under decoupled U(1) factors in the F-theory landscape. We also show that the charges can be even larger when the U(1) is coupled to other gauge groups.

TASI Lectures: (No) Global Symmetries to Axion Physics

“…This is a logical possibility, albeit one that seems implausible. However, the search for quantum gravity theories in which light fields have large integer U(1) charges has recently turned up interesting examples [195], so this remains an active area of investigation that may yet have surprises in store for us.…”

Towards natural and realistic E7 GUTs in F-theory

“…So far we have focused on the nonabelian part of the broken gauge group, but there may also be U(1) factors in the broken gauge group like G SM . In the formalism of flux breaking, there are two ways to get U(1) factors: for U(1) factors not along any roots, we can use vertical flux to get these factors using the Stückelberg mechanism; for a recent application see [65]. On the other hand, U(1) factors like the hypercharge in G SM are along some roots of a higher gauge group (SU(5) in the case of hypercharge), and remainder flux is necessary for obtaining these factors.…”