Title: Baryogenesis from the Kobayashi-Maskawa Phase Show Chinese title

Title: 从 Kobayashi-Maskawa 相位的重子生成

Abstract: The Standard Model fulfills the three Sakharov conditions for baryogenesis. The smallness of quark masses suppresses, however, the CP violation from the Kobayashi-Maskawa phase to a level that is many orders of magnitude below what is required to explain the observed baryon asymmetry. We point out that if, as a result of time variation in the Yukawa couplings, quark masses were large at the time of the electroweak phase transition, then the Kobayashi-Maskawa mechanism could be the source of the asymmetry. The Froggatt-Nielsen mechanism provides a plausible framework where the Yukawa couplings could all be of order one at that time, and settle to their present values before nucleosynthesis. The problems related to a strong first order electroweak phase transition may also be alleviated in this framework. Our scenario reveals a loophole in the commonly held view that the Kobayashi-Maskawa mechanism cannot be the dominant source of CP violation to play a role in baryogenesis. Show Chinese abstract

Abstract: 标准模型满足重子生成的三个萨哈罗夫条件。 然而，夸克质量的微小性将来自小林-益川相位的CP破坏抑制到远低于解释观测到的重子不对称性所需水平的级别。 我们指出，如果由于 Yukawa 耦合的时间变化，在电弱相变时期夸克质量较大，那么小林-益川机制可能是不对称性的来源。 Froggatt-Nielsen 机制提供了一个合理的框架，其中在那时所有的 Yukawa 耦合都可能处于数量级一的水平，并在核合成之前稳定到现在的值。 与此框架相关的强一阶电弱相变问题也可能得到缓解。 我们的场景揭示了一个常见的观点中的漏洞，即小林-益川机制不能是CP破坏的主要来源而在重子生成中发挥作用。