The Point of E_8 in F-theory GUTs

TL;DR

This paper demonstrates that a single E_8 enhancement point in F-theory GUTs explains flavor hierarchies, predicts specific supersymmetry breaking fields, and identifies gravitino as a dark matter candidate, with implications for recent astrophysical experiments.

Contribution

It reveals the necessity of an E_8 enhancement point for flavor hierarchies and supersymmetry breaking in F-theory GUTs, providing a unified geometric origin for these features.

Findings

E_8 point explains flavor hierarchies in F-theory GUTs.

Messenger fields in SUSY breaking transform as 10 + 10* of SU(5).

Gravitino with 10-100 MeV mass is a viable dark matter candidate.

Abstract

We show that in F-theory GUTs, a natural explanation of flavor hierarchies in the quark and lepton sector requires a single point of E_8 enhancement in the internal geometry, from which all Yukawa couplings originate. The monodromy group acting on the seven-brane configuration plays a key role in this analysis. Moreover, the E_8 structure automatically leads to the existence of the additional fields and interactions needed for minimal gauge mediated supersymmetry breaking,__and almost nothing else__. Surprisingly, we find that in all but one Dirac neutrino scenario the messenger fields in the gauge mediated supersymmetry breaking sector transform as vector-like pairs in the 10 + 10* of SU(5). We also classify dark matter candidates available from this enhancement point, and rule out both annihilating and decaying dark matter scenarios as explanations for the recent experiments PAMELA, ATIC and FERMI. In F-theory GUT models, a 10-100 MeV mass gravitino remains as the prime candidate for dark matter, thus suggesting an astrophysical origin for recent experimental signals.