Large-Scale Shell-Model Analysis of the Neutrinoless ββ Decay of ^{48}Ca.
Large-Scale Shell-Model Analysis of the Neutrinoless ββ Decay of ^{48}Ca.
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DOI：
10.1103/physrevlett.116.112502
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发表时间：
2016-02
影响因子：
8.6
通讯作者：
Yoritaka Iwata;N. Shimizu;T. Otsuka;Y. Utsuno;Javier Menéndez;M. Honma;T. Abe
中科院分区：
文献类型：
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作者：
Yoritaka Iwata;N. Shimizu;T. Otsuka;Y. Utsuno;Javier Menéndez;M. Honma;T. Abe
基于包括两个谐振子壳层(SD壳层和PF壳层)的大规模壳层模型计算，给出了^{48}Ca的无中微子双β衰变的核矩阵元.重现了^{48}Ca和^{48}Ti的激发谱，以及^{48}Ca的双中微子双β衰变，与实验数据符合得很好。我们发现，与PF壳层计算相比，无中微子双β衰变核矩阵元提高了约30%。这使衰变寿命减少了近2倍。矩阵元素的增加主要是由于与跨壳层SD-PF激发相关的成对关联。我们还研究了更重的无中微子双β衰变候选者的可能含义。
We present the nuclear matrix element for the neutrinoless double-beta decay of ^{48}Ca based on large-scale shell-model calculations including two harmonic oscillator shells (sd and pf shells). The excitation spectra of ^{48}Ca and ^{48}Ti, and the two-neutrino double-beta decay of ^{48}Ca are reproduced in good agreement to the experimental data. We find that the neutrinoless double-beta decay nuclear matrix element is enhanced by about 30% compared to pf-shell calculations. This reduces the decay lifetime by almost a factor of 2. The matrix-element increase is mostly due to pairing correlations associated with cross-shell sd-pf excitations. We also investigate possible implications for heavier neutrinoless double-beta decay candidates.