  We consider a geometric approach to field theory in which torsion is present
beside gravity and also electrodynamics for the matter field equations, and we
develop the consequences of the torsion-spin coupling for the spinor fields; we
show that these interactions have the structure of the weak interactions acting
among leptons: we discuss the implications for the standard model of
fundamental interactions of elementary fields in the perspective of the
foundations of unification in theoretical physics.
