Unified Models at Intermediate Energy Scales and Kaluza-Klein Excitations

TL;DR

This paper explores gauge coupling unification at intermediate energy scales in string-inspired models, emphasizing the role of Kaluza-Klein excitations and deriving conditions for unification in specific gauge symmetry frameworks.

Contribution

It introduces relations for beta-function coefficients that facilitate unification with Kaluza-Klein modes in models with specific gauge groups.

Findings

Derived conditions for coupling unification including Kaluza-Klein excitations.

Applied the framework to models with SU(3)^3 and SU(4)×O(4) gauge symmetries.

Provided insights into intermediate energy scale unification in string-inspired models.

Abstract

We discuss the possibility of intermediate gauge coupling unification in unified models of string origin. Useful relations of the \beta-function coefficients are derived, which ensure unification of couplings when Kaluza--Klein excitations are included above the compactification scale. We apply this procedure to two models with SU(3)\times SU(3)_L\times SU(3)_R and SU(4)\times O(4) gauge symmetries.