2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/192469We have calculated the Gamow-Teller matrix elements of 64 decays of nuclei in the mass range A=41--50. In all the cases the valence space of the full pf-shell is used. Agreement with the experimental results demands the introduction of an average quenching factor, q=0.744 +/- 0.015, slightly smaller but statistically compatible with the $sd$-shell value, thus indicating that the present number is close to the limit for large A.RevTeX v3.0 using epsf.sty, 4 Pages, 2 figures. Full postscript version available at http://www.ft.uam.es/~gabriel/ga-eff.ps.gzNuclear Theorytext