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Cosmological Constraints on MeV-scale Dark Sectors

MeV 级暗区的宇宙学约束

基本信息

批准号：
2169738
负责人：
金额：
--
依托单位：
King's College London
依托单位国家：
英国
项目类别：
Studentship
财政年份：
2018
资助国家：
英国
起止时间：
2018 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=studentship-2169738
关键词：
Cosmological Constraints MeV scale Dark

项目摘要

In this work we present new and refined cosmological constraints on MeV-scale dark sectors and various well-motivated particle physics models. New light states thermally coupled to the Standard Model plasma can alter the expansion history of the Universe and impact the synthesis of the primordial elements. We present precise and robust constraints from Big Bang Nucleosynthesis (BBN) and the Cosmic Microwave Background (CMB). We find that BBN observations alone set a lower bound on the thermal dark matter mass to be 0.4 MeV at 2 sigma significance. The reach of future CMB experiments is also considered. On a more terrestrial note, we reinterpret the results of direct detection experiments which rely on nuclear recoils. Such experiments lose sensitivity for sub-GeV dark matter although this is recovered if there is an additional, sub-dominant source of particles with higher momenta. We investigate the possibility that decays of mesons from inelastic cosmic ray collisions in the atmosphere could act as such a source. The resulting constraints are then presented and mapped onto a concrete particle physics model. Finally, we look at a well-motivated model that links neutrino masses and scalar dark matter. Bounds on parameters within the model are placed using measurements from the IceCube neutrino telescope and future sensitivity is forecast.

在这项工作中，我们提出了新的和改进的宇宙学约束在mev尺度的黑暗部门和各种良好的激励粒子物理模型。与标准模型等离子体热耦合的新光态可以改变宇宙的膨胀历史并影响原始元素的合成。我们提出了来自大爆炸核合成（BBN）和宇宙微波背景（CMB）的精确和稳健的约束。我们发现，仅BBN观测就将热暗物质质量的下界设定为0.4 MeV，具有2 σ显著性。展望了未来宇宙微波背景实验的范围。在更实际的情况下，我们重新解释依赖于核反冲的直接探测实验的结果。这样的实验对低于gev的暗物质失去了灵敏度，尽管如果有一个额外的、具有更高动量的次主导粒子源，这种灵敏度就会恢复。我们研究了大气中非弹性宇宙射线碰撞产生的介子衰变可能作为这样一个源的可能性。然后给出结果约束并将其映射到具体的粒子物理模型上。最后，我们将看到一个将中微子质量和标量暗物质联系起来的良好模型。利用冰立方中微子望远镜的测量结果确定了模型内参数的界限，并预测了未来的灵敏度。