On the D-branes Standard-like Models
  Based on the low-energy effective field theory of D-branes, the mass spectrum of an extended Standard Model with two-Higgs doublets used to generate all the mass terms is investigated. Besides the gauge bosons, the fermion mass spectrum is weighted by the Higgs VEVs with a partial hierarchy and the smallness of neutrino masses is exhibited. With reference to the known data, the involved scales of the model are approached. 
Salah-Eddine Ennadifi
hep-th