There is a well known anomaly between the value of the Fermi decay constant
extracted from super-allowed Fermi beta-decay of nuclear isotriplets and that
required by unitarity of the Cabibbo-Kobayashi-Maskawa matrix. This discrepancy
remains at the level of a few tenths of a percent after the most rigorous
investigation of conventional nuclear and radiative corrections. Within the
framework of the quark-meson coupling model of nuclear matter, which has been
previously applied successfully to phenomena such as nuclear saturation and
nuclear charge symmetry violation, we show that it is possible to understand a
significant fraction of the observed anomaly.Comment: 11 pages with 1 figure and 1 tabl
