Arnquist I J, Avignone F T, Barabash A S, Barton C J, Bhimani K H, Blalock E, Bos B, Busch M, Buuck M, Caldwell T S, Chan Y-D, Christofferson C D, Chu P-H, Clark M L, Cuesta C, Detwiler J A, Efremenko Yu, Ejiri H, Elliott S R, Giovanetti G K, Green M P, Gruszko J, Guinn I S, Guiseppe V E, Haufe C R, Henning R, Hervas Aguilar D, Hoppe E W, Hostiuc A, Kim I, Kouzes R T, Lannen V T E, Li A, Lopez A M, López-Castaño J M, Martin E L, Martin R D, Massarczyk R, Meijer S J, Oli T K, Othman G, Paudel L S, Pettus W, Poon A W P, Radford D C, Reine A L, Rielage K, Ruof N W, Tedeschi D, Varner R L, Vasilyev S, Wilkerson J F, Wiseman C, Xu W, Yu C-H, Zhu B X
Pacific Northwest National Laboratory, Richland, Washington 99354, USA.
Department of Physics and Astronomy, University of South Carolina, Columbia, South Carolina 29208, USA.
Phys Rev Lett. 2022 Aug 19;129(8):080401. doi: 10.1103/PhysRevLett.129.080401.
The Majorana Demonstrator neutrinoless double-beta decay experiment comprises a 44 kg (30 kg enriched in ^{76}Ge) array of p-type, point-contact germanium detectors. With its unprecedented energy resolution and ultralow backgrounds, Majorana also searches for rare event signatures from beyond standard model physics in the low energy region below 100 keV. In this Letter, we test the continuous spontaneous localization (CSL) model, one of the mathematically well-motivated wave function collapse models aimed at solving the long-standing unresolved quantum mechanical measurement problem. While the CSL predicts the existence of a detectable radiation signature in the x-ray domain, we find no evidence of such radiation in the 19-100 keV range in a 37.5 kg-y enriched germanium exposure collected between December 31, 2015, and November 27, 2019, with the Demonstrator. We explored both the non-mass-proportional (n-m-p) and the mass-proportional (m-p) versions of the CSL with two different assumptions: that only the quasifree electrons can emit the x-ray radiation and that the nucleus can coherently emit an amplified radiation. In all cases, we set the most stringent upper limit to date for the white CSL model on the collapse rate, λ, providing a factor of 40-100 improvement in sensitivity over comparable searches. Our limit is the most stringent for large parts of the allowed parameter space. If the result is interpreted in terms of the Diòsi-Penrose gravitational wave function collapse model, the lower bound with a 95% confidence level is almost an order of magnitude improvement over the previous best limit.
马约拉纳演示器无中微子双β衰变实验由一个44千克（其中30千克为富集(^{76}Ge)）的p型点接触锗探测器阵列组成。凭借其前所未有的能量分辨率和超低本底，马约拉纳实验还在100千电子伏特以下的低能区域寻找超出标准模型物理的罕见事件信号。在本信函中，我们测试了连续自发定域（CSL）模型，这是一种数学上动机充分的波函数坍缩模型，旨在解决长期未解决的量子力学测量问题。虽然CSL预测在X射线领域存在可探测的辐射信号，但我们在2015年12月31日至2019年11月27日期间用演示器收集的37.5千克·年的富集锗曝光量中，在19 - 100千电子伏特范围内未发现这种辐射的证据。我们用两种不同假设探索了CSL的非质量比例（n - m - p）和质量比例（m - p）版本：即只有准自由电子能发射X射线辐射以及原子核能相干发射放大辐射。在所有情况下，我们为白色CSL模型的坍缩率(\lambda)设定了迄今为止最严格的上限，在灵敏度上比同类搜索提高了40 - 100倍。我们的上限在允许参数空间的大部分区域是最严格的。如果根据迪奥西 - 彭罗斯引力波函数坍缩模型来解释结果，95%置信水平的下限比之前的最佳上限几乎提高了一个数量级。
