Improved description of the 2νββ-decay and a possibility to determine the effective axial-vector coupling constant
Improved description of the 2νββ-decay and a possibility to determine the effective axial-vector coupling constant
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改进了 2νββ 衰减的描述以及确定有效轴向矢量耦合常数的可能性
DOI：
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发表时间：
2018
期刊：
影响因子：
--
通讯作者：
A. Faessler
中科院分区：
文献类型：
--
作者：
F. vSimkovic;Rastislav Dvornick'y;D. vStef'anik;A. Faessler
提出了二中微子双β衰变（$2\nu\beta\beta$-decay）速率的改进形式，其中通过泰勒展开考虑了能量分母对轻子能量的依赖性。到目前为止，仅考虑了此扩展中的主导项。修正后的 $2\nu\beta\beta$ 衰变率和微分特性取决于具有不同能量分母幂的 $2\nu\beta\beta$ 衰变核矩阵元素的比率加权的附加相空间因子。对于实验感兴趣的核，所有相空间因子都是通过使用具有有限核尺寸和电子屏蔽的精确狄拉克波函数来计算的。对于测量的 $2\nu\beta\beta$ 衰变半衰期的同位素，所涉及的核基质元素是在具有部分同位旋恢复的准粒子随机相近似内确定的。建立了泰勒展开式修正项对 $2\nu\beta\beta$ 衰减率的重要性，并讨论了单个电子能量分布和总电子能量分布形状的修改。研究发现，$2\nu\beta\beta$衰变的改进计算预测了无中微子双β衰变信号的$2\nu\beta\beta$衰变背景的轻微抑制。此外，提出了一种确定核介质$g^{\rm eff}_{\rm A}$中有效弱耦合常数值的新方法。
An improved formalism of the two-neutrino double-beta decay ($2\nu\beta\beta$-decay) rate is presented, which takes into account the dependence of energy denominators on lepton energies via the Taylor expansion. Till now, only the leading term in this expansion has been considered. The revised $2\nu\beta\beta$-decay rate and differential characteristics depend on additional phase-space factors weighted by the ratios of $2\nu\beta\beta$-decay nuclear matrix elements with different powers of the energy denominator. For nuclei of experimental interest all phase-space factors are calculated by using exact Dirac wave functions with finite nuclear size and electron screening. For isotopes with measured $2\nu\beta\beta$-decay half-life the involved nuclear matrix elements are determined within the quasiparticle random phase approximation with partial isospin restoration. The importance of correction terms to the $2\nu\beta\beta$-decay rate due to Taylor expansion is established and the modification of shape of single and summed electron energy distributions is discussed. It is found that the improved calculation of the $2\nu\beta\beta$-decay predicts slightly suppressed $2\nu\beta\beta$-decay background to the neutrinoless double-beta decay signal. Further, a novel approach to determine the value of effective weak-coupling constant in nuclear medium $g^{\rm eff}_{\rm A}$ is proposed.
DOI：
10.1016/j.nuclphysa.2007.06.014
发表时间：
2007-09
期刊：
Nuclear Physics
影响因子：
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作者：
V. Rodin;P. Vogel;A. Faessler;F. Šimkovic
通讯作者：
V. Rodin;P. Vogel;A. Faessler;F. Šimkovic
影响因子：
64.8
作者：
Agostini, M.;Allardt, M.;Zuzel, G.
通讯作者：
Zuzel, G.