Are neutrinos with definite masses Majorana or Dirac particles? This is one of the most fundamental problems of modern neutrino physics. The solution to this problem could be crucial for understanding the origin of small neutrino masses. We review here basic arguments in favor of the Majorana nature of massive neutrinos. The phenomenological theory of $0\nu \beta \beta$-decay is briefly discussed and recent experimental data and sensitivity of future experiments are presented.

中文翻译：

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中微子：马约拉纳还是狄拉克？

中微子是具有一定质量的马约拉纳粒子还是狄拉克粒子？这是现代中微子物理学最基本的问题之一。这个问题的解决方案对于理解小型中微子质量的起源可能至关重要。我们在这里回顾基本论点，以支持大规模中微子的马约拉纳性质。的现象学理论$0\nu \beta \beta$简要讨论了衰变，并提供了最新的实验数据和未来实验的敏感性。