HAYSTAC Axion Dark Matter Experiment: Phase III

HAYSTAC Axion 暗物质实验：第三阶段

• 批准号: 2309631
• 负责人: Steven Lamoreaux
• 金额: $ 70万
• 依托单位: Yale University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-08-01 至 2026-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2309631&HistoricalAwards=false
• 关键词: HAYSTAC; Axion; Dark; Matter; Experiment

There are three astronomical observations that, to be understood, require the presence of so-called Dark Matter, which is invisible matter that almost exclusively interacts with itself and other matter through gravity. First, the velocities of stars bound in galaxies (including the Milky Way) are too fast to be accounted for by the total mass of the visible stars. Second, the expansion of the Universe requires the introduction of more matter than we can observe as ordinary atoms and particles. Third, the filamentary structure of the distribution of galaxies cannot be established based on gravitational interactions between galaxies, based on their observed masses. The fundamental nature of dark matter is one of the leading unsolved problems of modern science. Much work has been done to detect new types of massive dark matter particles that are predicted based on an extended theory of particle physics called supersymmetry. So far, no such particles have been seen in accelerator or dark matter detectors. Another possible theoretical dark matter particle is the axion, which was introduced to make the strong, or nuclear, force independent of the direction of time, as has been experimentally determined to very high precision. Although the axion has never been observed, its properties can be calculated, and it is perfect for a dark matter candidate. Such axions would form halos around galaxies, including our own. To search for axions, a microwave resonator is placed in a very strong magnetic field. The axions in the galactic halo can convert to photons, or radio waves, in the presence of the magnetic field. A sensitive amplifier is used to search for the signal arising from this conversion, the frequency of which is unknown. This system, called a haloscope, must be tuned slowly in frequency to search for the conversion signal. The group has operated the detector in the 4-7 GHz range several years and is continuing the search with a planned increase in sensitivity. The collaboration-wide efforts in support of HAYSTAC are leading to many technical innovations that will be useful in many research and technology fields, with the principal result being that it is possible to have a delicate quantum state measurement subsystem operate in a real-world system that is subject to vibration and very large magnetic fields, while operating with nearly 100% reliability, over times scales approaching a year. HAYSTAC also serves as a fantastic training ground for students and postdocs in particle physics, axion dark matter, and quantum sensing techniques. HAYSTAC (Haloscope at Yale Sensitive to Axion Cold Dark Matter) has been in continuous operation, with interruptions for system upgrades, since the initial commissioning in the Summer of 2014. The first version of the detector was based on a Josephson parametric amplifier that was able to reach the quantum noise limit of the phase-preserving amplifier. In 2019, the project successfully incorporated quantum-enhanced detection based on a squeeze-state receiver system that is not subject to the standard quantum limit. This increased the frequency scan speed by a factor of two with a modest increase in sensitivity, due to the approximately 4 dB of squeezing that was obtained, being limited by losses in the microwave circulators. This system is currently taking data in the 4.5 – 5 GHz range and will continue to do so through Summer 2023, with sensitivity at the KSVZ model level. The expertise that was developed from the beginning of HAYSTAC includes vibration suppression, accurate control of the conversion cavity frequency and coupling, and highly effective magnetic shielding of the quantum amplifiers that need to operate near the 8 Tesla superconducting magnet used for conversion. The project has developed operational techniques that allow continuous operation of the cryogenic system for months. During the first year of the proposed activity, the experiment will install a new multi-rod cavity that will allow operation at higher frequencies (favored by cosmogenic axion models) with a good volume form factor that is being developed at U.C. Berkeley, and test its cryogenic properties. Next, a new quantum enable receiver system being developed at the University of Colorado will be integrated into HAYSTAC. This system eliminates the lossy circulators and will allow a substantial increase in sensitivity. The group anticipates that the full commissioning of the upgraded system will be complete at the beginning in mid-2025, and operate in the 7-10 GHz range or above, with sensitivity well into the KSVZ parameter range.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.

有三个天文观测需要理解，需要所谓的暗物质的存在，暗物质是不可见的物质，几乎只通过引力与自身和其他物质相互作用。首先，星系（包括银河系）中恒星的速度太快，无法用可见恒星的总质量来解释。其次，宇宙的膨胀需要引入比我们作为普通原子和粒子所能观察到的更多的物质。第三，星系分布的结构不能建立在星系间的引力相互作用的基础上，根据它们的观测质量。暗物质的基本性质是现代科学尚未解决的主要问题之一。人们已经做了大量的工作来探测新类型的大质量暗物质粒子，这些粒子是基于一种称为超对称的粒子物理学扩展理论预测的。到目前为止，在加速器或暗物质探测器中还没有看到这样的粒子。另一种可能的理论暗物质粒子是轴子，它的引入是为了使强力或核力独立于时间的方向，这已经被实验确定为非常高的精度。虽然轴子从未被观测到，但它的性质可以计算出来，它是暗物质候选者的完美人选。这样的轴子会在星系周围形成晕，包括我们的星系。为了寻找轴子，将微波谐振器置于非常强的磁场中。星系晕中的轴子在磁场的存在下可以转换为光子或无线电波。一个灵敏的放大器被用来搜索从这种转换中产生的信号，其频率是未知的。这个系统称为晕圈仪，必须在频率上缓慢调谐以搜索转换信号。该小组已经在4-7 GHz范围内运行了几年，并正在继续进行搜索，计划提高灵敏度。支持HAYSTAC的合作范围内的努力正在导致许多技术创新，这些创新将在许多研究和技术领域中有用，主要结果是有可能在受到振动和非常大的磁场的真实世界系统中运行精细的量子态测量子系统，同时以接近100%的可靠性运行，时间尺度接近一年。HAYSTAC也是粒子物理学，轴子暗物质和量子传感技术的学生和博士后的绝佳培训场所。 HAYSTAC（Haloscope at Yale Sensitive to Axion Cold Dark Matter）自2014年夏季首次调试以来一直在持续运行，系统升级中断。第一个版本的探测器是基于约瑟夫森参量放大器，能够达到相位保持放大器的量子噪声极限。2019年，该项目成功地结合了基于不受标准量子限制的挤压态接收器系统的量子增强探测。这使频率扫描速度增加了两倍，灵敏度适度增加，因为获得了约4dB的压缩，受到微波环行器中损耗的限制。该系统目前正在4.5 - 5 GHz范围内采集数据，并将持续到2023年夏季，灵敏度达到KSVZ模型水平。从HAYSTAC成立之初就开发出的专业技术包括振动抑制、转换腔频率和耦合的精确控制，以及需要在用于转换的8特斯拉超导磁体附近运行的量子放大器的高效磁屏蔽。该项目开发了操作技术，使低温系统能够连续运行数月。在拟议活动的第一年，该实验将安装一个新的多棒腔，该腔将允许在更高的频率下运行（受宇宙起源轴子模型的青睐），具有良好的体积形状因子，正在U.C.开发。伯克利分校，并测试其低温性能。接下来，科罗拉多大学正在开发的一种新的量子接收器系统将被集成到HAYSTAC中。该系统消除了有损循环器，并将允许灵敏度的大幅增加。该集团预计，升级后的系统将在2025年年中完成全面调试，并在7-10 GHz或更高的范围内运行，灵敏度完全进入KSVZ参数范围。该奖项反映了NSF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。