Light Axion Dark Matter Search Using Toroidal Ferrite

暗物质可以说是超越标准模型的物理学最令人信服的证据。由于暗物质只能通过其引力效应被观察到，因此有广泛的可能的暗物质候选者，以及大量直接和间接的暗物质与标准模型粒子相互作用的搜索。轴子和类轴子粒子是突出的暗物质候选者：它们被弦理论启发的标准模型的扩展预测存在，被许多天体物理现象暗示，并且在量子色动学轴子的情况下，为强电荷宇称问题提供了一个优雅的解决方案。此外，发现轻的轴子状暗物质可能会提供宇宙最早期的见解，特别是暴胀的能量尺度。由该奖项资助的实验性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计划，并教授更适合复杂现实世界挑战的解决问题的技能和策略，将研究和推广结合起来。该计划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工作者和广大公众。该奖项将为通过轴子-光子相互作用直接实验寻找光轴子暗物质提供资金。轴子暗物质和磁化铁氧体环的方位磁化之间的这种相互作用产生了轴向磁场，以轴子康普顿频率振荡。SQUID磁力计感应耦合到样品以检测该场。将探索非谐振和谐振耦合方案，以找到本实验设计的最佳搜索策略。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之间的很宽的轴子质量范围。实验灵敏度范围超出了轴子-光子相互作用的现有界限几个数量级，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NSF的法定使命，并通过使用基金会的智力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.