等离子体效应抑制混合诱导的碰撞冻结入
Plasma Effects Suppress Mixing-Induced Collisional Freeze-In
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- Marietta Blau Institute for Particle Physics, Austrian Academy of Sciences（奥地利科学院玛丽亚·布劳粒子物理研究所）
- University of Vienna, Faculty of Physics（维也纳大学物理学院）
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中文总结 AI 辅助
本文利用Kadanoff-Baym方程证明等离子体效应同样抑制碰撞冻结入，以等离子体修正混合角替代真空混合角，并据此排除惰性中微子作为keV-MeV质量范围暗物质的可能性。
中文摘要 AI 辅助
与热等离子体中粒子弱混合的暗物质可以通过振荡和碰撞冻结入两种机制产生。虽然等离子体效应长期以来已知会抑制前者，但它们在碰撞冻结入中的作用在定量上仍不太清楚，导致在通过碰撞冻结入产生惰性中微子暗物质方面出现相互矛盾的结果。利用味协变表述中的第一性原理非平衡Kadanoff-Baym方程，我们建立了等离子体效应同样抑制碰撞冻结入的一般性结论：碰撞率中的真空混合角被其等离子体修正对应物所取代。应用这一结果，我们得出结论：当从标准模型等离子体产生时，惰性中微子不能成为keV-MeV质量范围内的暗物质。
英文摘要
Dark matter that is weakly mixed with particles in a thermal plasma can be produced through both, oscillatory and collisional freeze-in. While plasma effects have long been known to suppress the former, their role in collisional freeze-in remains less clear quantitatively, leading to conflicting results in sterile neutrino dark matter production via collisional freeze-in. Using first-principles nonequilibrium Kadanoff-Baym equations in the flavour-covariant formulation, we establish the general result that plasma effects also suppress collisional freeze-in: the vacuum mixing angle in the collision rate is replaced by its plasma-corrected counterpart. Applying this result, we conclude that sterile neutrinos cannot be dark matter in the keV-MeV mass range when produced from the Standard Model plasma.
