Assuming that the Standard Model arises from the $E_8\times E_8$ Heterotic Superstring, we try to solve the discrepancy between the unification scale predicted by this theory ($\approx g_{ GUT}\times 5.27\cdot 10^{ 17}$ GeV) and the value deduced from LEP experiments ($\approx 2\cdot 10^{ 16}$ GeV). This will allow us to predict the presence at low energies of three generations of supersymmetric Higgses and vector-like colour triplets.
Categories: hep-ph hep-th