Towards a Realistic F-theory GUT
James C. Callaghan, Stephen F. King, George K. Leontaris, G.G. Ross · 2016
We consider semi-local F-theory GUTs arising from a single E 8 point of local enhancement, leading to simple GUT groups based on E 6, SO(10) and SU(5) with SU(3), SU(4) and SU(5) spectral covers, respectively. Assuming the minimal $ {\mathcal{Z}_2} $ monodromy, we determine the homology classes and the associated spectra after flux breaking for each case. Using these results we construct an E 6 based model that demonstrates, for the first time, that it is possible to construct a phenomenologically viable model which leads to the MSSM at low energies. The exotics that result from flux breaking all get a large mass when singlet fields acquire vacuum expectation values driven by D- and F-flatness. Due to the underlying GUT symmetry and the U(1)s descending from E 8, bare baryon- and lepton-number violating terms are forbidden up to and including dimension 5. As a result nucleon decay is naturally suppressed below present bounds. The μ-term is generated by non-perturbative U(1) breaking effects. After including the effect of flux and instanton corrections acceptable quark and charged lepton masses and mixing angles can be obtained. Neutrinos get a mass from the see-saw mechanism through their coupling to singlet neutrinos that acquire large Majorana mass as a result of the monodromy.