Gauge Unification in Nonminimal Models with Extra Dimensions

TL;DR

This paper explores gauge unification in nonminimal models with extra dimensions, demonstrating that unification can be achieved without exotic matter or large threshold corrections, by selectively placing fields in the bulk.

Contribution

It introduces specific models with partial bulk matter fields that preserve gauge unification without requiring additional exotic multiplets or high string scales.

Findings

Gauge unification is possible with selective bulk matter placement.

Models do not require exotic matter beyond mirror fields for vector-like Kaluza-Klein excitations.

Unification can occur without large string scale threshold corrections.

Abstract

We consider gauge unification in nonminimal models with extra spacetime dimensions above the TeV scale. We study the possibility that only a a subset of the supersymmetric standard model gauge and Higgs fields live in the higher dimensional `bulk'. In two of the models we present, a choice for bulk MSSM matter fields can be found that preserves approximate gauge unification. This is true without the addition of any exotic matter multiplets, beyond the chiral conjugate mirror fields required to make the Kaluza-Klein excitations of the matter fields vector-like. In a third model, only a small sector of additional matter fields is introduced. In each of these examples we show that gauge unification can be obtained without the necessity of large string scale threshold corrections. We comment briefly on the phenomenology of these models in the case where the compactification scale is as low as possible.