  We consider the most general axial torsion completion of gravity with
electrodynamics for $\frac{1}{2}$-spin spinors in an $8$-dimensional
representation of the Dirac matter field: this theory will allow to define
antimatter as matter with all quantum numbers reversed, where also the sign of
the mass beside that of the charge is inverted: we shall see that matter and
antimatter solutions of the Dirac field equations coincide with the known ones
with respect to all observables, that despite the inversion of the sign of the
mass term only positive-mass states are present and only positive-energy
densities are given; the present and the common approach will be compared, and
some experimental implications will be discussed.
