发表机构
Università di Milano-Bicocca; INFN, Sezione di Milano - Bicocca; Politecnico di Milano; INFN, Sezione di Milano; Università degli Studi della Campania “Luigi Vanvitelli”; INFN, Sezione di Napoli; Università di Catania; INFN – Laboratori Nazionali del Sud (LNS); LENA – Laboratorio Energia Nucleare Applicata, Università di Pavia; Fondazione Bruno Kessler (FBK)（米兰比可卡大学; 意大利国家核物理研究所米兰-比可卡分部; 米兰理工大学; 意大利国家核物理研究所米兰分部; 坎帕尼亚路易吉范维泰利大学; 意大利国家核物理研究所那不勒斯分部; 卡塔尼亚大学; 意大利国家核物理研究所南部分实验室; 帕维亚大学应用核能实验室; 布鲁诺·凯斯勒基金会）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文首次用硅漂移探测器测量$^{99}$Tc的β谱，结合贝叶斯分析提取轴矢流和矢量流的平均淬灭因子，为核模型验证及无中微子双β衰变核矩阵元预测提供基准。
AI 中文摘要
对于下一代无中微子双β衰变实验而言，可靠计算核矩阵元的需求迫在眉睫。这要求核模型必须经过实验数据的验证，例如非唯一禁戒β衰变，这些衰变已被发现对核计算中的细节敏感，尤其是对轴矢流和矢量流的重整化。本文报道了首次使用硅漂移探测器（一种用于低能谱学的最先进半导体探测器）对2阶禁戒$^{99}$Tc β谱进行的测量。我们设计了一种新型混合谱仪，使用SiPM读出的LYSO晶体来精确校准主探测器并准确测量本底。然后，我们将测得的谱与使用低温量热器获得的谱以及Realistic Shell Model（RSM）的预测进行了比较。基于使用裸衰变算符进行的RSM计算，我们进行了贝叶斯分析，以提取重现实测谱形和实验半衰期所需的平均淬灭因子，得到$q_{g_A}=0.40(1)$和$q_{g_V}=0.47(1)$。这些值分别量化了轴矢流和矢量流的平均重整化，并与使用有效衰变算符的RSM计算预测值进行了比较，从而为评估该模型描述$^{99}\mathrm{Tc}$二阶禁戒β衰变的能力提供了基准。更广泛地说，这种比较检验了也用于预测$0\nu\beta\beta$核矩阵元的理论框架的可靠性。
英文摘要
The need for reliable calculations of Nuclear Matrix Elements is compelling for the next generation of neutrinoless double-beta decay experiments. This requires nuclear models to be validated against experimental data, such as non-unique forbidden $β$ decays, which have been found sensitive to details in nuclear calculations, most importantly to the renormalization of the axial and vector currents. %, parametrized as a quenching of $g_A$ and $g_V$. We report here a measurement of the 2$^{nd}$ forbidden $^{99}$Tc $β$ spectrum performed for the first time with Silicon Drift Detectors, state-of-the-art semiconductor detectors for low-energy spectroscopy. We designed a novel hybrid spectrometer using a LYSO crystal read by a SiPM to precisely calibrate our main detector and to accurately measure the background. We then compared our measured spectrum with one obtained using cryogenic calorimeters, as well as with predictions from the Realistic Shell Model. Starting from Realistic Shell Model calculations performed with Bare decay operators, we carried out a Bayesian analysis to extract the average quenching factors required to reproduce both the measured spectral shape and the experimental half-life, obtaining $q_{g_A}=0.40(1)$ and $q_{g_V}=0.47(1)$. These values quantify the average renormalization of the axial and vector currents, respectively, and were compared with those predicted by RSM calculations employing Effective decay operators, thereby providing a benchmark for assessing the ability of the model to describe the second-forbidden $β$ decay of $^{99}\mathrm{Tc}$. More broadly, this comparison tests the reliability of the theoretical framework also used to predict $0νββ$ nuclear matrix elements.
