标准模型味荷的宇宙演化
Cosmic Evolution of the Standard Model Flavor Charges
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中文总结 AI 辅助
该研究构建了味协变玻尔兹曼方程，推导适用于夸克 sector 重子生成的有效形式，验证了其一致性，还发布了通用重子生成公开代码BOLEH。
中文摘要 AI 辅助
由于所有标准模型（SM）参数已被精确测量至百分之一水平或更小，人们期望有一个框架能尽可能精确地描述重子生成过程，其中将测量得到的SM参数作为输入。在电弱对称性破缺之前的高温环境中，SM包含15个近似U(1)对称性及相关的味荷。为了以味基协变的方式描述这些味荷的演化，使得物理可观测量与味基无关，总共需要5个味空间中的密度矩阵：3个对应夸克，2个对应轻子。结合量子色动力学、电弱 sphaleron 相互作用以及所有汤川相互作用，我们得到了完整的味协变玻尔兹曼方程。通过在轻子部分施加化学平衡条件，我们进一步推导出一种新的有效夸克味协变形式，可用于重子生成发生在夸克部分产生数不对称的场景。为验证该完整形式的一致性，我们首先将其应用于轻子生成场景，重现了先前使用有效轻子味协变形式的结果，差异仅来自后者形式中使用的夸克化学平衡近似带来的小修正。随后，我们首次将完整形式和有效夸克味协变形式应用于重子生成发生在夸克部分产生数不对称的封闭重子生成场景，展示了两种形式结果的良好一致性。最后，我们发布了首个通用重子生成公开代码BOLEH（Hot大爆炸中的重子与轻子荷演化），其中考虑了所有SM相互作用。
英文摘要
Since all the Standard Model (SM) parameters have been measured to precision at the percent level or smaller, one would aim to have a framework which describes baryogenesis as precise as possible, where the measured SM parameters are used as inputs. At high temperature before the electroweak symmetry breaking, the SM contains 15 approximate $U(1)$ symmetries with the associated flavor charges. To describe the evolutions of these flavor charges in a flavor-basis-covariant manner such that physical observables are flavor-basis-independent, a total of five density matrices in flavor spaces are required: three for quarks and two for leptons. Taking into account the quantum chromodynamics and electroweak sphaleron interactions together with all the Yukawa interactions, we obtain the complete flavor-covariant Boltzmann equations. By imposing chemical equilibrium in the lepton sector, we further derive a new effective quark-flavor-covariant formalism which can be used when baryogenesis occurs through number asymmetry generation in the quark sector. To verify the consistency of this complete formalism, we first apply it to leptogenesis scenarios, reproducing previous results which utilize the effective lepton-flavor-covariant formalism up to small corrections due to the quark chemical equilibrium approximations used in the latter formalism. Then, for the first time, we apply the complete formalism as well as the effective quark-flavor-covariant formalism to a cloistered baryogenesis scenario where number asymmetries are generated in the quark sector, showcasing the good agreement between the results from the two formalisms. Finally, we release the first generic baryogenesis public code BOLEH (BaryOn and Lepton charge Evolution in the Hot big bang) where all the SM interactions are taken into account.
