旁观者暗物质与希格斯门户
Spectator Dark Matter and the Higgs Portal
- William I. Fine Theoretical Physics Institute, School of Physics and Astronomy, University of Minnesota（明尼苏达大学物理与天文学院威廉·I·芬理论物理研究所）
- Université Paris-Saclay, CNRS/IN2P3, IJCLab（巴黎萨克雷大学）
- University of Minnesota（明尼苏达大学）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
该研究提出通过极弱希格斯门户相互作用抑制暴胀期间旁观者标量场的随机涨落，避免暗物质过度产生，并支持亚GeV轻暗物质及低再加热温度，同时为冻结机制提供初始条件。
AI中文摘要：
轻标量旁观者在暴胀期间通常会获得大的随机涨落，如果由此产生的原初凝聚体存活到晚时，这可能导致暗物质的灾难性过度产生。我们证明，这种暴胀记忆可以通过一个极其微弱的希格斯门户相互作用（亚冻结耦合，$10^{-28} \lesssim \lambda_{HS} \lesssim 10^{-9}$）得到充分抑制。希格斯门户既诱导旁观者的辐射自相互作用，也诱导热质量，两者都可以导致振荡的提前开始和凝聚体能量密度的有效红移，而不会使旁观者热化或破坏凝聚体。希格斯门户还改变了旁观者涨落随机平衡分布，导致相对于孤立旁观者的场方差抑制。我们详细处理了暴胀可能没有持续足够长以使旁观者达到其涨落平衡分布的可能性，发现这种情景的主要约束来自等曲率扰动，这要求$N \gtrsim 10^{10}$ e-folds。我们还考虑了非最小引力耦合的加入，这显著扩展了参数空间。该模型通常偏好亚GeV轻暗物质（$0.1 \text{ eV} \lesssim m_S \lesssim 10 \text{ GeV}$），并且在缺乏非最小引力的情形下，它也偏好低再加热温度。虽然这种机制可以用亚冻结门户耦合提供全部遗迹丰度，但它也为标准希格斯门户冻结提供了自然的抑制初始条件。
英文摘要：
Light scalar spectators generically acquire large stochastic fluctuations during inflation, which can lead to a catastrophic overproduction of dark matter if the resulting primordial condensate survives until late times. We show that this inflationary memory can be sufficiently suppressed by an extremely feeble Higgs portal interaction with sub-freeze-in couplings ($10^{-28} \lesssim λ_{HS} \lesssim 10^{-9}$). The Higgs portal induces both a radiative self-interaction for the spectator as well as a thermal mass, both of which can lead to early onset of oscillations and efficient redshifting of the condensate's energy density without thermalizing the spectator or destroying the condensate. The Higgs portal also alters the stochastic equilibrium distribution of the spectator fluctuations, leading to a suppression of the field variance relative to an isolated spectator. We include a detailed treatment of the possibility that inflation may not have lasted sufficiently long for the spectator to reach its equilibrium distribution of fluctuations, finding the major constraint on such a scenario to come from isocurvature, which requires $N \gtrsim10^{10}$ e-folds. We also consider the addition of a non-minimal gravitational coupling, which extends the parameter space significantly. This model generally favors sub-GeV light dark matter ($0.1 \text{ eV} \lesssim m_S \lesssim 10 \text{ GeV}$) and in the absence of non-minimal gravity it also favors low reheating temperatures. While this mechanism can supply the entire relic abundance with sub-freeze-in portal couplings, it also naturally provides a suppressed initial condition for standard Higgs portal freeze-in.
