Ratio of the Gamow-Teller and Fermi Coupling Constants Determined fromftValues

A comparison is made of the ratios of the squares of the Gamow-Teller and Fermi coupling constants, CGT²CF², calculated from the latest experimental ft values and the theoretical matrix elements for the "doubly closed shell±{}one nucleon" mirror transitions and the 0⁺-0⁺ transitions. The ft value of the neutron derived from the recent half-life measurement of 11.7±{}0.3 minutes leads to a value for CGT²CF² of 1.42±{}0.06, which is in agreement with the ratio obtained from the correlation coefficient for the betaparticle momentum and the spin direction of the decaying neutron. The ft value for the decay of H³ is also in good agreement with this ratio if the Gamow-Teller matrix element for this transition does not differ appreciably from that predicted by the individual particle model. The ft value of the heavier mirror nuclei, O¹⁵, F¹⁷ and Ca³⁹, are consistent with a considerably lower ratio. In particular, O¹⁵ and F¹⁷, for which the Gamow-Teller matrix elements are considered the most reliable because the magnetic moments of the daughter nuclei are especially close to the Schmidt limits, lead to a value for CGT²CF² of 1.16±{}0.05. These results are consistent with recent theoretical considerations which suggest that meson exchange effects may give rise to appreciable corrections in the calculation of the matrix elements.