The recent literature shows a renewed interest, with various independent
approaches, in the classical theories for spin. Considering the possible
interest of those results, at least for the electron case, we purpose in this
paper to explore their physical and mathematical meaning, by the natural and
powerful language of Clifford algebras (which, incidentally, will allow us to
unify those different approaches). In such theories, the ordinary electron is
in general associated to the mean motion of a point-like "constituent" Q, whose
trajectory is a cylindrical helix. We find, in particular, that the object Q
obeys a new, non-linear Dirac-like equation, such that --when averaging over an
internal cycle (which corresponds to linearization)-- it transforms into the
ordinary Dirac equation (valid for the electron as a whole).Comment: LaTeX; 19 pages; this is a corrected version of work appeared partly
in Hadronic J. 18 (1995) 97 and partly in Phys.Lett. B318 (1993) 48