论文标题
早期宇宙中小混合的无菌中微子产生
Sterile neutrino production at small mixing in the early universe
论文作者
论文摘要
无菌中微子可以通过与活性对应物的相互作用在早期宇宙中产生。对于小的活动性混合角，未达到具有标准模型血浆的热平衡，而无菌中微子仅通过风味振荡产生。我们考虑了由于血浆弹性散射引起的物质潜力和破坏作用，因此我们详细研究了这种制度。我们发现，在温度下发生的共振振荡$ t \ lyssim 10 \，\ mathrm {gev} $导致无菌中微子生产率的显着提高。考虑到这一点，我们改善了对大爆炸核合成和宇宙微波背景的积极性混合的限制，不包括混合到$θ_s\ sim 10^{ - 10} -10} -10} -10} -10^{ - 16} $，用于$ 10 \，\，\ nmerm {mev} $ {mev} $ {eg v} $ {eg v} $ {g，to $ 10 范围。我们观察到，如果无菌中微子主要腐烂成亚稳态的隐藏扇形颗粒，则此过程提供了一种新型的暗物质生产机制，与通过Seesaw机制的光中微子质量的无菌中微子起源一致。
Sterile neutrinos can be produced in the early universe via interactions with their active counterparts. For small active-sterile mixing angles, thermal equilibrium with the standard model plasma is not reached and sterile neutrinos are only produced via flavor oscillations. We study in detail this regime, taking into account matter potentials and decoherence effects caused by elastic scatterings with the plasma. We find that resonant oscillations occurring at temperatures $T\lesssim 10\,\mathrm{GeV}$ lead to a significant enhancement of the sterile neutrino production rate. Taking this into account, we improve constraints on the active-sterile mixing from Big Bang nucleosynthesis and the cosmic microwave background, excluding mixing angles down to $θ_s\sim 10^{-10}-10^{-16}$ for sterile neutrino masses in the $10\,\mathrm{MeV}$ to $10\,\mathrm{GeV}$ range. We observe that if sterile neutrinos predominantly decay into metastable hidden sector particles, this process provides a novel dark matter production mechanism, consistent with the sterile neutrino origin of light neutrino masses via the seesaw mechanism.
