轴子驱动的自发轻子生成，精确求解
Axion-driven spontaneous leptogenesis, precisely
AI总结：
该研究提出轴子驱动自发轻子生成的精确方案，推导B-L不对称性主公式，证明耦合到sphaleron的轴子可成功产生观测到的重子不对称性。
AI中文摘要：
我们重新研究了自发轻子生成的最小场景，其中不对称性的产生由通过标准错位机制演化的重类轴子场驱动。我们聚焦于最简单的框架，其中轻子数违反源于五维温伯格算符，且标准热轻子生成的贡献可忽略不计。通过求解一组输运方程计算不对称性，这些输运方程纳入了温伯格算符的全味依赖相互作用率，该相互作用率在此首次呈现。我们还推导了所产生的B-L不对称性的简单代数主公式，该公式对任意轴子速度和与标准模型的经典 shift 对称耦合均有效，在可控参数区域内可复现完整输运方程组的B-L产生动力学。在此过程中，我们量化了低能标中微子质量及两种质量排序对所产生不对称性最终预测的重要性。最后，我们通过考虑后期轴子衰变的熵稀释并施加重子等曲率扰动的约束，评估了不同轴子耦合的宇宙学可行性。我们证明，由于后期衰变的稀释，通过标准马约龙错位机制解释重子不对称性面临严重张力；相比之下，耦合到强或弱 sphaleron 的轴子，在衰变常数接近大统一能标、轴子振荡温度$T_{\text{osc}} \rsg 10^{11\twelve}$ GeV，且具备包含高能标暴胀和高效再加热的宇宙学历史时，可成功产生观测到的不对称性。
英文摘要：
We revisit a minimal scenario for spontaneous leptogenesis where the asymmetry generation is driven by a heavy axion-like field evolving via standard misalignment. We focus on the simplest framework in which lepton number violation originates from the dimension-five Weinberg operator and contributions from standard thermal leptogenesis become negligible. The asymmetry is computed by solving a set of transport equations, which incorporate fully flavor-dependent interaction rates for the Weinberg operator that are presented here for the first time. We also derive a simple algebraic master formula for the generated $B\!-\!L$ asymmetry, valid for arbitrary axion velocities and classically shift-symmetric couplings to the Standard Model, that reproduces the $B\!-\!L$-production dynamics of the full set of transport equations in controlled parameter regions. Along the way, we quantify the importance of low-scale neutrino masses and the two mass orderings on the final prediction for the generated asymmetry. Finally, we assess the cosmological viability of different axion couplings by accounting for entropy dilution from late-time axion decays and imposing constraints from baryonic isocurvature perturbations. We demonstrate that explaining the baryon asymmetry via standard Majoron misalignment is under severe tension due to dilution from late-time decays. In contrast, axions coupled to strong or weak sphalerons can successfully produce the observed asymmetry for decay constants near the energy scale of grand unification and axion oscillation temperatures $T_{\text{osc}} \gtrsim 10^{11\cdots12}$ GeV, provided a cosmological history featuring high-scale inflation and efficient reheating.
