Dark Matter: from the Universe to the Lattice

暗物质：从宇宙到晶格

• 批准号: RGPIN-2020-06165
• 负责人: Tulin, Sean
• 金额: $ 2.48万
• 依托单位: York University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=741067
• 关键词: Dark; Matter; Universe; Lattice

Dark matter governs the structure of the cosmos, from the smallest galaxies to the observable Universe. Through its gravitational pull on visible stars and gas, we can infer that dark matter makes up 85% of the total matter in the Universe. However, the microphysical properties of dark matter remain unknown despite intense scientific inquiry spanning high and low energy experiments and astronomical observations. While it is firmly established that dark matter exists through its gravity, the key to uncovering its nature lies in detecting its interactions beyond gravity. This proposal in theoretical physics focuses on the particle physics and astrophysics of dark matter and dark sectors. Under this hypothesis, dark matter particles have interactions and forces among themselves, analogous to the rich physics of visible matter and its strong, weak, and electromagnetic interactions. Under this broad theme, I will pursue two parallel research objectives. First, I will investigate tidal streams in the Milky Way as a probe of dark matter substructure. Tidal streams are the tidally-disrupted remnants of globular clusters, which, being dynamically fragile, are easily disrupted by dark matter clumps in the Milky Way. Therefore, tidal streams provide a method for detecting invisible substructures predicted to exist for dark matter that are otherwise completely invisible since they are too small to bind stars and gas on their own. Depending on the underlying particle model for dark matter, clumps are predicted to be concentrated or diffuse or absent altogether. This physics may be related to the long-standing core-cusp problem for rotation curves in galaxies. These observations are consistent with the dark sector model for cored dark matter profiles that more diffuse compared to the cuspy profiles predicted theoretically. However, the jury is still out due to the confounding influence of gas and stars. I will look to tidal streams to settle this controversy once and for all. Free from the confounding effect of stars and gas, tidal streams have the potential to measure the density profiles for substructures that purely dark matter. Second, I will explore the physics of strongly-interacting dark sectors. Dark matter models along these lines are appealing theoretically, but remain under-explored due to the breakdown of the usual Feynman-diagram-based approaches. I will use lattice field theory to study the interactions of dark matter particles within a minimal strongly-interacting dark sector. I will investigate the formation of dark elements through fusion between dark matter particles. I will also calculate the scattering cross section for dark matter particles with one another. These effects can influence phenomenology and astrophysics of dark matter, potentially providing new signatures for discovering its properties.

暗物质支配着宇宙的结构，从最小的星系到可观测的宇宙。通过它对可见恒星和气体的引力，我们可以推断暗物质占宇宙总物质的85%。然而，暗物质的微物理性质仍然未知，尽管激烈的科学调查跨越高，低能量实验和天文观测。虽然暗物质是通过其引力存在的，但揭示其本质的关键在于检测其引力之外的相互作用。这一理论物理学的建议侧重于暗物质和暗区的粒子物理和天体物理。在这个假设下，暗物质粒子之间有相互作用和相互作用力，类似于可见物质的丰富物理学及其强、弱和电磁相互作用。在这一广泛的主题下，我将追求两个平行的研究目标。首先，我将研究银河系中的潮汐流作为暗物质子结构的探测器。潮汐流是球状星团被潮汐破坏的残余物，由于动态脆弱，很容易被银河系中的暗物质团块破坏。因此，潮汐流提供了一种方法来探测暗物质的不可见子结构，这些子结构被预测为存在于暗物质中，否则它们是完全不可见的，因为它们太小了，无法单独束缚恒星和气体。根据暗物质的基本粒子模型，团块被预测为集中或扩散或完全不存在。这种物理现象可能与长期存在的星系旋转曲线的核心尖点问题有关。这些观测结果与核心暗物质剖面的暗扇区模型相一致，与理论预测的尖形剖面相比，暗物质剖面更具扩散性。然而，由于气体和恒星的混杂影响，陪审团仍然无法确定。我将指望潮汐流一劳永逸地解决这一争议。没有恒星和气体的干扰，潮汐流有可能测量纯暗物质的子结构的密度分布。其次，我将探索强相互作用暗区的物理学。沿着这些路线的暗物质模型在理论上是有吸引力的，但由于通常的基于费曼图的方法的崩溃，仍然没有得到充分的探索。我将使用格点场论来研究暗物质粒子在最小强相互作用暗扇区内的相互作用。我将研究通过暗物质粒子之间的融合形成暗元素。我还将计算暗物质粒子相互之间的散射截面。这些效应可以影响暗物质的现象学和天体物理学，可能为发现其性质提供新的签名。