Title: First Evidence for Neutrinoless Double Beta Decay Show Chinese title

Title: 中微子无双β衰变的首次证据

Abstract: Double beta decay is indispensable to solve the question of the neutrino mass matrix together with $\nu$ oscillation experiments. Recent analysis of the most sensitive experiment since nine years - the HEIDELBERG-MOSCOW experiment in Gran-Sasso - yields a first indication for the neutrinoless decay mode. This result is the first evidence for lepton number violation and proves the neutrino to be a Majorana particle. We give the present status of the analysis in this report. It excludes several of the neutrino mass scenarios allowed from present neutrino oscillation experiments - only degenerate scenarios and those with inverse mass hierarchy survive. This result allows neutrinos to still play an important role as dark matter in the Universe. To improve the accuracy of the present result, considerably enlarged experiments are required, such as GENIUS. A GENIUS Test Facility has been funded and will come into operation by early 2003. Show Chinese abstract

Abstract: 双β衰变对于解决中微子质量矩阵的问题是必不可少的，这需要与$\nu$振荡实验相结合。 最近对九年来最灵敏的实验——格兰-萨索的海德堡-莫斯科实验的分析，首次提供了无中微子衰变模式的迹象。 这一结果是轻子数破坏的第一个证据，并证明了中微子是一种马约拉纳粒子。 在本报告中，我们给出了目前的分析状态。 它排除了从目前中微子振荡实验允许的几种中微子质量情景——只有简并情景和逆质量层次的情景得以保留。 这一结果使得中微子仍然可以在宇宙中扮演重要的暗物质角色。 为了提高目前结果的准确性，需要进行显著扩大的实验，例如GENIUS。 一个GENIUS测试设施已经获得资助，并将在2003年初投入运行。