Most of the free parameters in the Standard Model (SM) --- a quantum field theory which has successfully elucidated the behaviors of strong, weak and electromagnetic interactions of all the known fundamental particles, come from the lepton and quark flavors. The discovery of neutrino oscillations has proved that the SM is incomplete, at least in its lepton sector; and thus the door of opportunity is opened to exploring new physics beyond the SM and solving a number of flavor puzzles. In this review article we give an overview of important progress made in understanding the mass spectra, flavor mixing patterns, CP-violating effects and underlying flavor structures of charged leptons, neutrinos and quarks in the past twenty years. After introducing the standard pictures of fermion mass generation, flavor mixing and CP violation in the SM extended with the presence of massive Dirac or Majorana neutrinos, we briefly summarize current experimental knowledge about the flavor parameters of quarks and leptons. Various ways of describing flavor mixing and CP violation are discussed, the renormalization-group evolution of flavor parameters is illuminated, and the matter effects on neutrino oscillations are interpreted. Taking account of possible extra neutrino species, we propose a standard parametrization of the $6\times 6$ flavor mixing matrix and comment on the phenomenological aspects of heavy, keV-scale and light sterile neutrinos. We pay particular attention to those novel and essentially model-independent ideas or approaches regarding how to determine the Yukawa textures of Dirac fermions and the effective mass matrix of Majorana neutrinos, including simple discrete and continuous flavor symmetries. An outlook to the future development in unravelling the mysteries of flavor structures is also given.

中文翻译：

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带电费米子和大量中微子的风味结构

标准模型 (SM) 中的大部分自由参数——一种量子场论，它成功地阐明了所有已知基本粒子的强、弱和电磁相互作用的行为，来自轻子和夸克的味道。中微子振荡的发现证明了SM是不完整的，至少在它的轻子扇区是不完整的；因此，探索超越 SM 的新物理和解决许多风味难题的机会之门打开了。在这篇综述文章中，我们概述了过去 20 年来在理解带电轻子、中微子和夸克的质谱、风味混合模式、CP 违反效应和潜在风味结构方面取得的重要进展。介绍完费米子质量生成的标准图片后，SM 中的风味混合和 CP 违反随着大量狄拉克或马约拉纳中微子的存在而扩展，我们简要总结了当前有关夸克和轻子风味参数的实验知识。讨论了描述风味混合和 CP 破坏的各种方法，阐明了风味参数的重整化群演化，并解释了物质对中微子振荡的影响。考虑到可能存在的额外中微子种类，我们提出了 $6\times 6$ 风味混合矩阵的标准参数化，并评论了重、keV 级和轻无菌中微子的现象学方面。我们特别关注那些关于如何确定狄拉克费米子的汤川结构和马约拉纳中微子的有效质量矩阵的新颖且基本上独立于模型的想法或方法，包括简单的离散和连续风味对称性。还给出了解开风味结构之谜的未来发展前景。