Light Axion Dark Matter Search Using Toroidal Ferrite

暗物质可以说是超越标准模型的最令人信服的物理证据。由于暗物质仅通过其引力效应被观测到，因此存在大量可能的暗物质候选者，以及大量对暗物质与标准模型粒子相互作用的直接和间接搜索。轴子和类轴子粒子是重要的暗物质候选者：它们被预测存在于弦理论启发的标准模型扩展中，被许多天体物理现象所暗示，并且，在量子色动力轴子的情况下，为强电荷宇称问题提供了一个优雅的解决方案。此外，发现类似光轴子的暗物质可能会让我们了解宇宙最早的时代，特别是暴胀的能量规模。由该奖项资助的实验研究有可能揭示这些重要的谜题。该奖项通过开发一个旨在激发年轻学生和公众对科学的兴趣的项目，将研究和推广结合起来，并教授更适合复杂的现实世界挑战的解决问题的技能和策略。这个项目将包括创建一个非标准概念物理问题的集合，这些问题将通过万维网提供给物理教育者和广大公众。该奖项将为通过轴-光子相互作用直接实验寻找轻轴子暗物质提供资金。这种轴子暗物质与磁化铁氧体环面体的方位磁化之间的相互作用产生了一个轴向磁场，以轴子康普顿频率振荡。为了检测该磁场，将SQUID磁力计电感耦合到样品上。为了找到适合本实验设计的最优搜索策略，我们将探索非谐振和谐振耦合方案。该装置将放置在液氦低温恒温器内，超导磁屏蔽将用于屏蔽外部电磁干扰。实验的目标是在~ 10^-16 eV和10^-8 eV之间的非常宽的轴子质量范围。实验灵敏度超出了现有轴子-光子相互作用的几个数量级，探索了许多天体物理观测所青睐的耦合范围，例如宇宙对TeV光子的透明度。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Dark matter is arguably the most compelling evidence of physics beyond the Standard Model. Since dark matter has only been observed through its gravitational effects, there is a wide range of possible dark matter candidates, and a large number of direct and indirect searches for dark matter interactions with standard model particles. Axions and axion-like particles are prominent dark matter candidates: they are predicted to exist by string-theory-inspired extensions of the Standard Model, are hinted at by a number of astrophysical phenomena, and, in the case of the QuantumChromoDynamic axion, offer an elegant solution to the strong-Charge-Parity problem. In addition, discovery of light axion-like dark matter may provide insights into the earliest epochs of the universe, specifically the energy scale of inflation. The experimental search funded by this award has the potential to shed light on these important puzzles. This award integrates research and outreach by developing a program designed to spark interest in science among young students and the general public, and to teach problem solving skills and strategies that are better-suited to complex real-world challenges. This program will include creating a collection of non-standard conceptual physics problems that will be made available to physics educators and the broad public via the world-wide-web.This award will provide funds for a direct experimental search for light axion dark matter, via the axion-photon interaction. This interaction between axion dark matter and the azimuthal magnetization of a magnetized ferrite toroid creates an axial magnetic field, oscillating at the axion Compton frequency. A SQUID magnetometer is inductively coupled to the sample in order to detect this field. Both non-resonant and resonant coupling schemes will be explored, in order to find the optimal search strategy for this experimental design. The apparatus will be placed inside a liquid helium cryostat, and superconducting magnetic shielding will be used to screen external electromagnetic interference. The experiment targets a very broad range of axion masses between ~ 10^-16 eV and 10^-8 eV. The experimental sensitivity reach extends several orders of magnitude beyond existing bounds on axion-photon interaction, exploring the range of couplings that are favored by a number of astrophysical observations, such as the transparency of the universe to TeV photons.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.