How to Reach the Correct sin^2θ_W and α_S in String Theory

Abstract

Effective theories with the matter content of the minimal supersymmetric Standard Model below the string scale M_string predict a wrong value for the weak--mixing angle sin^2θ_W and strong coupling constant α_S at the scale M_Z. To resolve this problem one needs large threshold corrections. At the same time one would like to avoid introducing new intermediate scales that are small compared to M_string. Two requests which seem to be incompatible. We show how both requirements can be satisfied in a class of (0,2) heterotic superstring compactifications with a natural choice of the vevs of the moduli fields entering the moduli dependent string threshold corrections.

11 LaTex pages with 2 figures

References in corpus (3)

• Moduli Dependence of One--Loop Gauge Couplings in (0,2) Compactifications
• Making Ends Meet: String Unification and Low-Energy Data
• Threshold corrections in orbifold models and superstring unification of gauge interactions

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