The discovery of neutrinoless $\beta \beta$ decay could soon be within reach. This hypothetical ultrarare nuclear decay offers a privileged portal to physics beyond the standard model of particle physics. Its observation would constitute the discovery of a matter-creating process, corroborating leading theories of why the Universe contains more matter than antimatter, and how forces unify at high energy scales. It would also prove that neutrinos and antineutrinos are not two distinct particles but can transform into each other, with their mass described by a unique mechanism conceived by Majorana. The recognition that neutrinos are not massless necessitates an explanation and has boosted interest in neutrinoless $\beta \beta$ decay. The field stands now at a turning point. A new round of experiments is currently being prepared for the next decade to cover an important region of parameter space. In parallel, advances in nuclear theory are laying the groundwork to connect the nuclear decay with the underlying new physics. Meanwhile, the particle theory landscape continues to find new motivations for neutrinos to be their own antiparticle. This review brings together the experimental, nuclear theory, and particle theory aspects connected to neutrinoless $\beta \beta$ decay to explore the path toward, and beyond, its discovery.

中文翻译：

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探索无中微子ββ衰变物质的创造

无中微子的发现$\beta \beta$腐烂可能很快就会到来。这种假设的超稀有核衰变为超越粒子物理学标准模型的物理学提供了一个独特的门户。它的观测将构成对物质创造过程的发现，证实为什么宇宙含有比反物质更多的物质，以及力如何在高能尺度上统一的主要理论。它还将证明中微子和反中微子不是两种不同的粒子，而是可以相互转化，其质量由马约拉纳构想的独特机制描述。认识到中微子不是无质量的，需要一个解释，并增加了对中微子的兴趣$\beta \beta$衰变。该领域现在正处于一个转折点。目前正在为未来十年准备新一轮的实验，以覆盖参数空间的重要区域。与此同时，核理论的进步正在为将核衰变与潜在的新物理学联系起来奠定基础。与此同时，粒子理论领域继续寻找中微子成为其自身反粒子的新动机。这篇综述汇集了与无中微子相关的实验、核理论和粒子理论方面$\beta \beta$腐烂来探索通往和超越其发现的道路。