  The long standing problem of non perturbative renormalization of a gauge
field theoretical Hamiltonian is addressed and explicitly carried out within an
(effective) light-cone Hamiltonian approach to QCD. The procedure is in line
with the conventional ideas: The Hamiltonian is first regulated by suitable
cut-off functions, and subsequently renormalized by suitable counter terms to
make it cut-off independent. The formalism is applied to physical mesons with a
different flavor of quark and anti-quark. The excitation spectrum of the
$\rho$-meson with its excellent agreement between theory and experiment is
discussed as a pedagogical example.

High Energy Physics - Phenomenology