发表机构
School of Physics and Astronomy, Shanghai Jiao Tong University（上海交通大学物理与天文学院）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本研究揭示重中微子质量层级通过延迟N1冲刷时机改变味退相干状态，从而反转非热轻子生成中的重子不对称性，其中无迹CP源分量主导时机效应。
AI 中文摘要
我们研究为何改变重中微子质量层级会反转山顶暴胀后非热轻子生成中的重子不对称性。在所研究的质量轨迹上，降低较轻态N1的质量会反转最终不对称性，同时使来自N2衰变的主导注入几乎不变。质量变化主要延迟了N1相对于电子-缪子味退相干的冲刷；在固定源和背景下，平移冲刷历史同时保持其形状和积分强度，在两个物理目标质量下可重现来自非热N2源的产额变化的99%以上。分解N2 CP源表明，在两种冲刷历史下，投影对齐分量保持为正，而初始无迹分量反转其传播贡献，并在固定源比较中约占时机对比的99.7%。eμ味相干性的快速阻尼在很大程度上消除了这一对比，而快速化学平衡则不能。因此，较晚的冲刷作用于更退相干的味态，减少了正的eμ贡献，并允许负的对角贡献决定最终符号。在重新计算以重现观测到的重子产额的质量下，缪子碰撞算子增加10%会在固定输入敏感性测试中反转符号。
英文摘要
We investigate why changing the heavy-neutrino mass hierarchy can reverse the baryon asymmetry in nonthermal leptogenesis after hilltop inflation. Along the mass trajectory studied here, lowering the mass of the lighter state, \(N_1\), reverses the final asymmetry while leaving the dominant injection from \(N_2\) decays nearly unchanged. The mass change primarily delays \(N_1\) washout relative to electron--muon flavor decoherence; at fixed source and background, translating the washout history while preserving its shape and integrated strength reproduces more than 99\% of the yield changes from the nonthermal \(N_2\) source at two physical target masses. Decomposing the \(N_2\) CP source shows that the projector-aligned component remains positive under both washout histories, whereas the initially trace-free component reverses its propagated contribution and accounts for about 99.7\% of the timing contrast in the fixed-source comparison. Rapid damping of \(eμ\) flavor coherence largely removes this contrast, while rapid chemical equilibration does not. Later washout therefore acts on a more decohered flavor state, reducing the positive \(eμ\) contribution and allowing negative diagonal contributions to determine the final sign. At a mass recomputed to reproduce the observed baryon yield, a 10\% increase of the muon collision operator reverses the sign in a fixed-input sensitivity test.
Comments24 pages, 3 figures
