Precision Tests of Fundamental Interactions

Half-life measurement provides clearer view of the weak force

Half-life measurement provides clearer view of the weak force: Scientists using GRIFFIN achieved a half-life measurement of magnesium-22 (22Mg) three times more precise than the previously adopted world average. As reported in Physical Review C (2017), this high-precision measurement provides a clearer view of the dynamics of the weak force. Precision measurements of the ft values for superallowed Fermi β-decay transitions between isobaric analog states provide fundamental tests of the Standard Model's description of electroweak interaction. These transitions provide a stringent test of the conserved vector-current (CVC) hypothesis, and in combination with other values, they also provide the most precise determination of Vud, the most precisely determined element of the Cabibbo-Kobayashi-Maskawa quark-mixing matrix. Researchers used a 4π proportional gas counter and the GRIFFIN spectrometer to make the 22Mg half-life measurement, resolving a discrepancy between the two previously published 22Mg half-life measurements.