Non-universal $Z'$ from Fluxed GUTs

Abstract

We make a first systematic study of non-universal TeV scale neutral gauge bosons $Z'$ arising naturally from a class of F-theory inspired models broken via $SU(5)$ by flux. The phenomenological models we consider may originate from semi-local F-theory GUTs arising from a single $E_8$ point of local enhancement, assuming the minimal ${\cal Z}_2$ monodromy in order to allow for a renormalisable top quark Yukawa coupling. We classify such non-universal anomaly-free $U(1)'$ models requiring a minimal low energy spectrum and also allowing for a vector-like family. We discuss to what extent such models can account for the anomalous $B$-decay ratios $R_{K}$ and $R_{K^*}$.