Gauge Unification in Extra Dimensions: Power Corrections vs. Higher-Dimension Operators

TL;DR

This paper explores how power corrections to gauge couplings in higher-dimensional supersymmetric theories can be precisely understood and calculated using higher-dimension operators, potentially enabling TeV-scale gauge unification.

Contribution

It demonstrates that power corrections in 5d supersymmetric GUTs are governed by higher-dimension operators, allowing for unambiguous, non-perturbative predictions of gauge coupling unification.

Findings

Power corrections are constrained by gauge symmetry and supersymmetry.

Non-perturbative contributions to unification can be precisely calculated.

A 5d SU(5) model exhibits MSSM-like power-law unification.

Abstract

Power-like loop corrections to gauge couplings are a generic feature of higher-dimensional field theories. In supersymmetric grand unified theories in d=5 dimensions, such corrections arise only in the presence of a vacuum expectation value of the adjoint scalar of the gauge multiplet. We show that, using the analysis of the exact quantum effective action by Intriligator, Morrison and Seiberg, these power corrections can be understood as the effect of higher-dimension operators. Such operators, both classical and quantum, are highly constrained by gauge symmetry and supersymmetry. As a result, even non-perturbatively large contributions to gauge coupling unification can be unambiguously determined within 5d low-energy effective field theory. Since no massive hypermultiplet matter exists in 6 dimensions, the predictivity is further enhanced by embedding the 5d model in a 6d gauge theory relevant at smaller distances. Thus, large and quantitatively controlled power-law contributions to gauge couplings arise naturally and can, in the most extreme case, lead to calculable TeV-scale power law unification. We identify a simple 5d SU(5) model with one massless 10 in the bulk where the power-law effect is exactly MSSM-like.