Flavor changing neutral current constraints on standard-like orbifold   models
  We examine for standard-like orbifold compactification models the constraints due to quarks and leptons generation non-universality of soft supersymmetry breaking interactions. We follow the approach initiated by Ibanez and Lust and developed by Brignole, Ibanez and Munoz. The breaking of supersymmetry is represented in terms of dilaton and moduli auxiliary field components and, consistently with a vanishing cosmological constant, is parametrized in terms of the dilaton-moduli mixing angle $\theta $ and the gravitino mass scale $m_g$. The soft breaking interactions (gaugino masses, squarks and sleptons mass matrices, scalars interactions A and B coupling constants) are calculable as a function of these parameters and of the discrete set of modular weight parameters specifying the modular transformation properties of the low-energy fields. We solve the renormalization group one-loop equations for the full set of gauge, Yukawa and supersymmetry breaking coupling constants. 
P. Brax and M. Chemtob