High-Precision Half-Life Measurements for the Superallowed β+ Emitter C 10: Implications for Weak Scalar Currents
Precision measurements of superallowed Fermi β-decay transitions, particularly for the lightest superallowed emitters C10 and O14, set stringent limits on possible scalar current contributions to the weak interaction. In the present work, a discrepancy between recent measurements of the C10 half-life is addressed through two high-precision half-life measurements, via γ-ray photopeak and β counting, that yield consistent results for the C10 half-life of T1/2=19.2969±0.0074 s and T1/2=19.3009±0.0017 s, respectively. The latter is the most precise superallowed β-decay half-life measurement reported to date and the first to achieve a relative precision below 10-4. A fit to the world superallowed β-decay data including the C10 half-life measurements reported here yields bF=-0.0018±0.0021 (68% C.L.) for the Fierz interference term and CS/CV=+0.0009±0.0011 for the ratio of the weak scalar to vector couplings assuming left-handed neutrinos.
Publication Source (Journal or Book title)
Physical Review Letters
Dunlop, M., Svensson, C., Ball, G., Grinyer, G., Leslie, J., Andreoiu, C., Austin, R., Ballast, T., Bender, P., Bildstein, V., Diaz Varela, A., Dunlop, R., Garnsworthy, A., Garrett, P., Hackman, G., Hadinia, B., Jamieson, D., Laffoley, A., Maclean, A., Miller, D., Mills, W., Park, J., Radich, A., Rajabali, M., Rand, E., Unsworth, C., Valencik, A., Wang, Z., & Zganjar, E. (2016). High-Precision Half-Life Measurements for the Superallowed β+ Emitter C 10: Implications for Weak Scalar Currents. Physical Review Letters, 116 (17) https://doi.org/10.1103/PhysRevLett.116.172501