Berkooz Micha, Nir Yosef, Volansky Tomer
Department of Particle Physics, Weizmann Institute of Science, Rehovot 76100, Israel.
Phys Rev Lett. 2004 Jul 30;93(5):051301. doi: 10.1103/PhysRevLett.93.051301. Epub 2004 Jul 27.
The smallness of quark masses suppresses 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 1 at that time, and settle to their present values before nucleo-synthesis. 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.
夸克质量极小，将小林-益川相位导致的CP破坏压低到比解释观测到的重子不对称所需水平低许多数量级的程度。我们指出，如果由于汤川耦合的时间变化，夸克质量在电弱相变时很大，那么小林-益川机制可能是不对称性的来源。弗罗格特-尼尔森机制提供了一个合理的框架，在该框架中，汤川耦合在那时可能都为1量级，并在核合成之前稳定到它们目前的值。在这个框架中，与强一阶电弱相变相关的问题也可能得到缓解。我们的设想揭示了一个普遍观点中的漏洞，即小林-益川机制不可能是在重子生成中起作用的CP破坏的主要来源。
