  A standard model is formulated in a Weyl space, $W_4$, yielding a Weyl
covariant dynamics of massless chiral Dirac fermion fields for leptons and
quarks as well as the gauge fields involved for the groups D(1)\,(Weyl),
$U(1)_Y{\times} SU(2)_W$\,(electroweak), $SU(3)_c$\,(colour),
SO(3,1)\,(gravity) and SO(4,1)\,(strong interaction, symmetry breaking). The
dynamics is based on a gauge and Weyl invariant Lagrangean density ${\cal L}$.
Gravitation is included from the beginning as the gauge aspect of the Lorentz
group which is here extended in the hadronic sector of the model to the ten
parameter SO(4,1) de Sitter group. A part of the dynamics is, as usual, a
scalar isospinor field $\phi$ being a section on a bundle related to the
electroweak gauge group and to symmetry breaking. In parallel to $\phi$ on the
leptonic side a section $\tilde\xi^a$ on the hadronic side is considered as
part of the dynamics, governing the symmetry breaking $SO(4,1)\longrightarrow
SO(3,1)$ and recovering gravitation in the symmetry breaking limit outside the
regions in space-time where strong interactions persist. Besides spin, isospin
and helicity the Weyl weights determine the form of the contributions of fields
in ${\cal L}$. Of particular interest is the appearance of a current-current
self-interaction of quark fields allowed by the Weyl weight changing the debate
about quark masses. In a second step the D(1)-Weyl symmetry is explicitly
broken and a universal mass scale is established through the mass of the
$\phi$-field appearing in the symmetry breaking Lagrangean ${\cal L}_B$. The
Weyl symmetry breaking is governed by the relation $D_\mu \Phi^2{=}0$, where
$\Phi$ is the norm of $\phi$. After D(1) symmetry breaking the masses of the
weak bosons and of the electron appear on the scene through the energy-momentum
tensor of the $\phi$-field.
