Fermions on the brane in 6D with nonsingular exponential scale factors
  We introduce new realistic brane-solutions with exponential scale factors in the 6D-space-time. We show that for these solutions the zero modes of all bulk fields are sharply localized at different positions on the brane and have "Gaussian shape" wave-functions in the extra space. We also explicitly show that in the model there are cases when exactly three fermion generations naturally arise only through gravity. Because of localized fermion modes are also stuck at different positions in the extra space, there is possibility to provide a framework for natural explaining the fermion mass hierarchy in terms of higher dimensional geography. 
P.Midodashvili