Gauge Coupling Unification in Superstring Derived Standard–like Models

I discuss gauge coupling unification in a class of superstring standard–like models, which are derived in the free fermionic formulation. Recent calculations indicate that the superstring unification scale is at O(10GeV ) while the minimal supersymmetric standard model is consistent with LEP data if the unification scale is at O(10)GeV . A generic feature of the superstring standard–like models is the appearance of extra color triplets (D, D̄), and electroweak doublets (l, l̄), in vector–like representations, beyond the minimal supersymmetric standard model. I show that gauge coupling unification at O(10GeV ) in the superstring standard– like models can be consistent with LEP data. I present an explicit standard–like model that can realize superstring gauge coupling unification.