2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/198989Using the correlation function of the axial vector mesons, we present a QCD sum rule calculation for the decay constants f_pi and f_K. Our calculations are only weakly dependent on the SU(3) breaking-parameter for the QCD vacuum and give the ratio f_K/f_pi = 1.11 $\pm$ 0.02.revtex, 17 pages; erratum (with a more detailed analysis) added. results are slightly changedNuclear TheoryHigh Energy Physics - Phenomenologytext