用 CUPID-0 研究 ^{82}Se 的双β衰变中存在单态主导

Evidence of Single State Dominance in the Two-Neutrino Double-β Decay of ^{82}Se with CUPID-0.

机构信息

INFN Laboratori Nazionali di Legnaro, I-35020 Legnaro (Padua), Italy.

Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.

出版信息

Phys Rev Lett. 2019 Dec 31;123(26):262501. doi: 10.1103/PhysRevLett.123.262501.

DOI:10.1103/PhysRevLett.123.262501

PMID:31951429

Abstract

We report on the measurement of the two-neutrino double-β decay of ^{82}Se performed for the first time with cryogenic calorimeters, in the framework of the CUPID-0 experiment. With an exposure of 9.95 kg yr of Zn^{82}Se, we determine the two-neutrino double-β decay half-life of ^{82}Se with an unprecedented precision level, T_{1/2}^{2ν}=[8.60±0.03(stat) _{-0.13}^{+0.19}(syst)]×10^{19} yr. The very high signal-to-background ratio, along with the detailed reconstruction of the background sources allowed us to identify the single state dominance as the underlying mechanism of such a process, demonstrating that the higher state dominance hypothesis is disfavored at the level of 5.5σ.

摘要

我们报告了首次使用 cryogenic calorimeters 对 ^{82}Se 的双β衰变进行的测量，该实验是 CUPID-0 实验的一部分。在 Zn^{82}Se 的暴露量为 9.95 kg·yr 的情况下，我们以空前的精度水平确定了 ^{82}Se 的双β衰变半衰期，T_{1/2}^{2ν}=[8.60±0.03(stat) _{-0.13}^{+0.19}(syst)]×10^{19} yr。高的信号与背景比，以及对背景源的详细重建，使我们能够确定单一态优势是这一过程的潜在机制，这表明在 5.5σ 的水平上，更高态优势的假设是不被支持的。