A Simplified Scheme for GUT-inspired Theories with Multiple Abelian Factors

TL;DR

This paper introduces a simplified method for handling multiple Abelian factors in GUT-inspired theories, avoiding loop-induced gauge kinetic mixing through a strategic basis choice, with extensions to supersymmetric models.

Contribution

It presents a general scheme for choosing a basis to prevent gauge kinetic mixing in GUT-inspired theories with multiple Abelian factors, including supersymmetric extensions.

Findings

Loop-induced gauge kinetic mixing can be avoided in many cases.

A basis choice can eliminate mixing at the one-loop level.

The scheme is extended to supersymmetric theories with soft SUSY breaking.

Abstract

Grand Unified Theories often involve additional Abelian group factors apart from the standard model hypercharge, that generally lead to loop-induced mixing gauge kinetic terms. In this letter, we show that at the one-loop level this effect can be avoided in many cases by a suitable choice of basis in group space and present a general scheme for the construction of this basis. In supersymmetric theories however, a residual mixing in the soft SUSY breaking gaugino mass terms may appear. We generalize the renormalization group equations for the gaugino mass terms to account for this effect. In a further calculation we also present the necessary adjustments in the renormalization group equations of the trilinear soft breaking couplings and the soft breaking scalar mass squares.