Brane world unification of quark and lepton masses and its implication   for the masses of the neutrinos
  A TeV-scale scenario is constructed in an attempt to understand the relationship between quark and lepton masses. This scenario combines a model of early (TeV) unification of quarks and leptons with the physics of large extra dimensions. It demonstrates a relationship between quark and lepton mass scales at rather ``low'' (TeV) energies which will be dubbed as {\em early quark-lepton mass unification}. It also predicts that the masses of the neutrinos are naturally light and Dirac. There is an interesting correlation between neutrino masses and those of the unconventionally charged fermions which are present in the early unification model. If these unconventional fermions were to lie between 200 GeV and 300 GeV, the Dirac neutrino mass scale is predicted to be between 0.07 eV and 1 eV. 
P. Q. Hung