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。由于暗物质只是通过引力效应被观察到，因此有很多种可能的暗物质候选者，以及大量直接和间接搜索暗物质与标准模型粒子相互作用的方法。轴子和类似轴子的粒子是重要的暗物质候选者：它们通过弦理论启发的标准模型的扩展而被预测存在，被一些天体物理现象暗示，并且在量子色动力学轴子的情况下，为强电荷宇称问题提供了一个优雅的解决方案。此外，类光轴子暗物质的发现可能会提供对宇宙最早时期的洞察，特别是膨胀的能量规模。由该奖项资助的实验性搜索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普通公众对科学的兴趣的计划，并教授更适合于复杂现实世界挑战的解决问题的技能和策略，将研究和推广结合在一起。该计划将包括创建一组非标准概念物理问题，通过万维网向物理教育工作者和广大公众提供。该奖项将提供资金，通过轴子-光子相互作用直接实验探索光轴子暗物质。轴子暗物质和磁化铁氧体磁环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。一台SQUID磁强计被电感耦合到样品上，以检测该磁场。非谐振耦合方案和共振耦合方案都将被探索，以找到该实验设计的最优搜索策略。该装置将被放置在液氦低温恒温器内，并将使用超导磁屏蔽来屏蔽外部电磁干扰。该实验的目标是大约10^-16 eV到10^-8 eV之间的非常广泛的轴子质量。该实验灵敏度范围将轴子-光子相互作用的现有界限扩展了几个数量级，探索了一些天体物理观测支持的耦合范围，例如宇宙对TeV光子的透明度。这一奖项反映了NSF的法定使命，并通过使用基金会的智力优势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.