论文标题
$^{62} $ ga superaldoed $β$衰减的高精度分支比率测量和旋转分配含义
High-Precision Branching Ratio Measurement and Spin Assignment Implications for $^{62}$Ga Superallowed $β$ Decay
论文作者
论文摘要
对超级允许的Fermi $β{+} $发射器$^{62} $ GA进行的高精度分支比率测量是通过伽马射线基础架构进行的，用于对同位素分离器和Accelator（ISAC）放射性离子射击设施的基础研究（Griffin）光谱计的基本研究。 Griffin光谱仪的高效率允许63 $γ$ -Ray的过渡，其强度降至每百万$ 1零件（每百万$^{62} $^{62} $ ga $ ga $β^{+} $衰减，以nucleus $^{62} $ zn的级别放置在$ zn $^{62} $ ga衰减为99.8577 $^{+0.0023} _ { - 0.0029} \％$，比以前的世界平均值高4个。对于几个级联，进行了$γ-γ$角相关测量，以分配自旋和/或确定过渡的混合比。特别是，在女儿核$^{62} $ Zn中，2.342 MEV激发状态的旋转定义为$ j = 0 $。该任务解决了以前的测量之间的差异，并且对Isospin对称性破坏校正具有重要影响，$δ_{C1} $，$^{62} $ ga $ ga superforeed fermi $β$衰减。
A high-precision branching ratio measurement for the superallowed Fermi $β^{+}$ emitter $^{62}$Ga was performed with the Gamma-Ray Infrastructure for Fundamental Investigations of Nuclei (GRIFFIN) spectrometer at the Isotope Separator and Accelerator (ISAC) radioactive ion beam facility at TRIUMF. The high efficiency of the GRIFFIN spectrometer allowed 63 $γ$-ray transitions, with intensities down to $\approx$1 part per million (ppm) per $^{62}$Ga $β^{+}$ decay, to be placed in the level scheme of the daughter nucleus $^{62}$Zn, establishing the superallowed $β$ branching ratio for $^{62}$Ga decay to be 99.8577$^{+0.0023}_{-0.0029}\%$, a factor of 4 more precise than the previous world average. For several cascades, $γ-γ$ angular correlation measurements were performed to assign spins and/or determine the mixing ratios of transitions. In particular, the spin of the 2.342 MeV excited state in the daughter nucleus $^{62}$Zn was definitively assigned as $J = 0$. This assignment resolves a discrepancy between previous measurements and has important implications for the isospin symmetry breaking correction, $δ_{C1}$, in $^{62}$Ga superallowed Fermi $β$ decay.
