Minimal String Unification in Orbifold Models

Abstract

We study the minimal supersymmetric standard model derived from orbifold models. We use a target-space duality anomaly cancellation and a unification of gauge couplings as constraints. The allowed levels of U(1)γ are calculated for the MSSM derived from the orbifold models. Further we investigate the hidden sectors consistent with the observable MSSM under the anomaly cancellation and estimate the gauge coupling constants of the hidden sectors. The calculation is important from the point of view of the gaugino condensation, which is one of the most promissing mechanism to break the supersymmetry.