Effective μ-term in superstring theory☆

Abstract In four-dimensional compactifications of the heterotic superstring theory the Kahler potential has a form which generilly induces a superpotential mass term for Higgs particles once supersymmetry is broken at low energies. This “μ-term” is analyzed in a model-independent way at the tree level and in the one-loop approximation, and explicit expressions are obtained for orbifold compactifications. Additional contributions which arise in the case of supersymmetry breaking induced by gaugino condensation are also discussed.