Ball G C, Bishop S, Behr J A, Boisvert G C, Bricault P, Cerny J, D'Auria J M, Dombsky M, Hardy J C, Iacob V, Leslie J R, Lindner T, Macdonald J A, Mak H B, Moltz D M, Powell J, Savard G, Towner I S
TRIUMF, Vancouver, British Columbia, Canada.
Phys Rev Lett. 2001 Feb 19;86(8):1454-7. doi: 10.1103/PhysRevLett.86.1454.
Presently, the world data for superallowed beta decay leads to a result in disagreement (at the 98% confidence level) with the predictions of the minimal standard model for the unitarity of the Cabibbo-Kobayashi-Maskawa matrix. Precise data for the superallowed 0(+)-->0(+) beta decay of (74)Rb would provide a critical test of the nucleus-dependent isospin symmetry-breaking corrections that must be calculated for these superallowed Fermi beta decays. The present work reports the first precise measurement of the half-life for (74)Rb ( t(1/2) = 64.761+/-0.031 ms). The data were obtained at the radioactive beam facility (ISAC) at TRIUMF using a beam of approximately 4000 (74)Rb ions s(-1).
目前，世界上关于超允许β衰变的数据导致了一个与卡比博-小林-益川矩阵幺正性的最小标准模型预测不一致的结果（在98%置信水平）。对于(^{74}Rb)的超允许(0(+) \to 0(+))β衰变的精确数据，将为这些超允许费米β衰变必须计算的与原子核相关的同位旋对称性破缺修正提供关键检验。本工作报道了(^{74}Rb)半衰期的首次精确测量（(t_{1/2} = 64.761 \pm 0.031)毫秒）。数据是在加拿大 TRIUMF 实验室的放射性束流装置（ISAC）上，使用每秒约4000个(^{74}Rb)离子束获得的。
