  The fermionic sector of the Standard Model of Elementary Particles emerges as
the low energy limit of a single fermionic field freely propagating in a higher
dimensional background. The local geometrical framework is obtained by
enforcing at a space-time level the whole gauge group SO(1,3) x U(1) x SU(2) x
SU(3) associated to fundamental interactions; equivalently, by assuming that
internal gauge transformations are indeed local space-time transformations. The
geometry naturally embodies freedoms corresponding to gravitational and
non-gravitational gauge fields. As a consequence of the fact that the
structural group is in part unitary, the motion of test particles gets
automatically squeezed on an effective 1+3 space-time. Dimensional reduction
takes place without compactification. In close analogy to the special
relativistic mass-energy relation, the theory associates to every elementary
particle an intrinsic energy presumably of the order of the Planck scale. The
theory predicts the existence of a right-handed component of the neutrino and
indicates the possibility of an extra U(1) gauge interaction.
