2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/47172The formulation of QCD which contains no divergences and no renormalization procedure is presented. It contains both perturbative and non-perturbative phenomena. It is shown that, due to its asymptotically free nature, the theory is not defined uniquely. The chiral symmetry breaking and the nature of the octet of pseudo-scalar particles as quasi-Goldstone states are analysed in the theory with massless and massive quarks. The U(1) problem is discussed.39 pages, Latex, 115 figures included using epsfig.styHigh Energy Physics - Phenomenologytext