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arXiv 1111.6421hep-ph
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中微子混合之谜

The Mystery of Neutrino Mixings

Guido Altarelli

摘要:

在过去的几年里,我们学到了很多关于中微子质量和混合的知识。中微子并不都是无质量的,但它们的质量非常小。中微子的质量可能很小,因为中微子是马约拉纳粒子,其质量与轻子数(L)破坏的大尺度M成反比,这与GUT尺度是相容的。我们已经知道,大中微子混合和小夸克混合之间并不矛盾,即使在大统一理论的背景下也是如此,而且中微子质量也很好地符合超对称大统一理论的图像。重RH中微子的CP和L破坏的平衡衰变可以产生B-L不对称性,然后在弱标度附近被瞬子转换成与观测相符的B不对称性(通过轻生的重子生成)。看来活跃的中微子并不是宇宙中暗物质的重要组成部分。多年来,为了理解中微子的质量和混合,人们制定了一长串模型。随着数据的不断完善,大部分模型已经被实验所抛弃。幸存的模型仍然跨越了很大的范围,从最大的对称性,离散的非阿贝尔味道组,到相反的极端无政府状态。

英文摘要:

In the last years we have learnt a lot about neutrino masses and mixings. Neutrinos are not all massless but their masses are very small. Probably masses are small because neutrinos are Majorana particles with masses inversely proportional to the large scale M of lepton number (L) violation, which turns out to be compatible with the GUT scale. We have understood that there is no contradiction between large neutrino mixings and small quark mixings, even in the context of GUTs and that neutrino masses fit well in the SUSY GUT picture. Out of equilibrium decays with CP and L violation of heavy RH neutrinos can produce a B-L asymmetry, then converted near the weak scale by instantons into an amount of B asymmetry compatible with observations (baryogenesis via leptogenesis). It appears that active neutrinos are not a significant component of Dark Matter in the Universe. A long list of models have been formulated over the years to understand neutrino masses and mixings. With the continuous improvement of the data most of the models have been discarded by experiment. The surviving models still span a wide range going from a maximum of symmetry, with discrete non-abelian flavour groups, to the opposite extreme of anarchy.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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