为什么是三代？
Why three generations?
摘要：
我们讨论了为什么存在三代费米子的人择解释。如果我们假设右手中微子扇区是造成物质-反物质不对称和暗物质的原因，那么人择选择倾向于三个或更多的费米子家族。为了成功地实现稀薄生成，至少需要两个右手中微子，而第三个右手中微子则被用来扮演暗物质的角色。右手中微子的数量与产生的次数是由$U(1)_{B-L}$规范对称性的反常约束决定的。结合人择参数与观测约束，我们得到的预测的$X$射线观测，以及为中微子双β衰变。
英文摘要：
We discuss an anthropic explanation of why there exist three generations of fermions. If one assumes that the right-handed neutrino sector is responsible for both the matter-antimatter asymmetry and the dark matter, then anthropic selection favors three or more families of fermions. For successful leptogenesis, at least two right-handed neutrinos are needed, while the third right-handed neutrino is invoked to play the role of dark matter. The number of the right-handed neutrinos is tied to the number of generations by the anomaly constraints of the $U(1)_{B-L}$ gauge symmetry. Combining anthropic arguments with observational constraints, we obtain predictions for the $X$-ray observations, as well as for neutrinoless double-beta decay.
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。
