2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/42984The 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 $ρ$-meson with its excellent agreement between theory and experiment is discussed as a pedagogical example.LaTeX2e, 10 pages, 5 figures, 24 references. Invited talk at LC03 at IPPP Durham, 5--9 August 2003High Energy Physics - Phenomenologytext