Branching ratio forC10superallowed Fermi β decay

Currents and Their Couplings in the Weak Sector of the Standard Model

“…The f t value that characterizes a particular β-transition is determined by three measured parameters: the transition energy, Q EC , which is used in calculating the statistical rate function, f ; the half-life, t 1/2 , of the β-emitter and the branching ratio, R, for the transition of interest, which together yield the partial half-life, t. World data have been surveyed recently 12 for eight of the best-known superallowed emitters: 14 O, 26m Al, 34 Cl, 38m K, 42 Sc, 46 V, 50 Mn and 54 Co. The results given in Table 2 are drawn from that survey, augmented by data on 10 C decay 13,14,15,16,17,18,19,20,21 and by several other recent measurements of significance. 22,23,24,25,26,27,28,29 The experimental uncertainties quoted for the measured decay energies (typically 1 part in 20,000), half-lives (1 part in 3,000) and branching ratios (1 part in 70,000) are at the limits of what is currently possible.…”

“…It is then a straightforward matter with these inputs to eliminate λ and, allowing for experimental uncertainties, to set limits 210,211,212,213 on ζ and δ. A similar analysis 214 can be performed for the mirror transition in the decay of 19 Ne, for which the beta asymmetry and lifetime have been determined. Carnoy et al 214 have also performed a combined fit to both data sets and obtain at the 90% confidence level: δ = 0.12 ± 0.04 and ζ = −0.003 ± 0.009.…”

“…β-ν angular correlations. The classic e − ν correlation data were obtained by observation of the lepton-recoil effect on the energy distribution of stable daughter nuclei from 6 He, 19 Ne, 23 Ne and 35 Ar decays. Such experiments are very difficult because the recoil energies are only a few hundred eV.…”

Branching ratio of the super-allowed beta decay of 10C

“…Freeman Robinson Kroupa Nagai Fujikawa Savard average et al [2] et al [3] et al [4] et al [5] et al [6] et al [7] et al [8] [1] 1.65(20) % 1.523(30) % 1.465(14) % 1.465(9) % 1.473(7) % 1.4625(25) % 1.4665(38) % 1.4646(19) % Before the present work, the world data for 10 C decay were as follows [1]:…”