The Conformal Sector of F-theory GUTs

TL;DR

This paper explores D3-brane probes in F-theory GUTs, revealing new conformal fixed points, small anomalous dimensions for MSSM fields, and improved gauge coupling unification, with implications for SUSY breaking scenarios.

Contribution

It identifies a new class of N=1 conformal fixed points from D3-brane probes and analyzes their effects on MSSM coupling and unification.

Findings

Discovery of computable infrared R-charges at fixed points

Small anomalous dimensions for MSSM fields due to weak coupling

Calculable threshold corrections improve gauge coupling unification

Abstract

D3-brane probes of exceptional Yukawa points in F-theory GUTs are natural hidden sectors for particle phenomenology. We find that coupling the probe to the MSSM yields a new class of N = 1 conformal fixed points with computable infrared R-charges. Quite surprisingly, we find that the MSSM only weakly mixes with the strongly coupled sector in the sense that the MSSM fields pick up small exactly computable anomalous dimensions. Additionally, we find that although the states of the probe sector transform as complete GUT multiplets, their coupling to Standard Model fields leads to a calculable threshold correction to the running of the visible sector gauge couplings which improves precision unification. We also briefly consider scenarios in which SUSY is broken in the hidden sector. This leads to a gauge mediated spectrum for the gauginos and first two superpartner generations, with additional contributions to the third generation superpartners and Higgs sector.