Wilson Lines and a Canonical Basis of SU(4) Heterotic Standard Models

TL;DR

This paper investigates the breaking of SU(4) heterotic models to the MSSM using Wilson lines, identifying a unique basis for uncorrelated soft parameters and analyzing gauge coupling unification.

Contribution

It introduces a canonical basis for SU(4) heterotic models with uncorrelated soft parameters and no kinetic mixing, and explores intermediate models with gauge unification from string theory spectra.

Findings

Unique basis for soft parameters with no kinetic mixing.

Intermediate models with gauge unification at different scales.

Direct computation of spectra from string theory.

Abstract

The spontaneous breaking of SU(4) heterotic standard models by Z_3 x Z_3 Wilson lines to the MSSM with three right-handed neutrino supermultiplets and gauge group SU(3)_C x SU(2)_L x U(1) x U(1) is explored. The two-dimensional subspace of the Spin(10) Lie algebra that commutes with su(3)_C + su(2)_L is analyzed. It is shown that there is a unique basis for which the initial soft supersymmetry breaking parameters are uncorrelated and for which the U(1) x U(1) field strengths have no kinetic mixing at any scale. If the Wilson lines "turn on" at different scales, there is an intermediate regime with either a left-right or a Pati-Salam type model. We compute their spectra directly from string theory, and adjust the associated mass parameter so that all gauge parameters exactly unify. A detailed analysis of the running gauge couplings and soft gaugino masses is presented.