Collaborative Research: The SuperCDMS SNOLAB Experiment

观测表明，宇宙中85%的物质不是由正常原子组成的，而是不发射或吸收光的未被检测到的基本“暗物质”粒子。值得注意的是，由于其他原因而提出的粒子物理学理论预测了弱相互作用大质量粒子（WIMP）的存在，这些粒子的性质恰好是这种暗物质。如果WIMP是暗物质，那么当它们在地球上的探测器中散射时，它们可能是可以探测到的。对WIMP暗物质的直接探测将解决粒子物理学和宇宙学中的一个基本谜团，为了解宇宙的主要物质成分和粒子物理学标准模型之外的物理学提供了一个独特的窗口。在过去的三年里，SuperCDMS合作在寻找低质量暗物质方面处于领先地位。 CDMSlite的最新结果达到了电子反冲的能量阈值低至56 eV。这些结果排除了新的参数空间的暗物质核子自旋无关的横截面的暗物质质量之间的1.6和5.5 GeV/c2。 该项目将专注于更好地理解信号探测器的响应，以推动SuperCDMS更加灵敏。SuperCDMS SNOLAB实验将产生广泛的影响，其范围超出了对暗物质的搜索。该实验的声子介导探测器在宇宙学，天文学和工业中有应用。这一努力将为培养本科生、研究生和博士后研究人员提供机会。SuperCDMS将在当地机构开展教育和外联活动，并将协调在SNOLAB和南达科他州的桑福德地下研究设施（SURF）的外联活动，以增加更广泛的影响，重点是中等教育。该奖项将支持参与SNOLAB主办的教师研讨会，修改和提供中学暗物质教育模块给美国教育工作者，并为加拿大和SURF的SNOLAB维护SuperCDMs相关的外展材料。现有的联盟将使外联到萨德伯里第一民族社区。为了最大限度地提高超级CDMS SNOLAB的科学产出，需要详细了解探测器对潜在信号和背景的响应。在两个地下设施（费米实验室的NEXUS和SNOLAB的CUTE）进行的测量将表征和校准预生产的SuperCDMS SNOLAB探测器和第一批生产的SuperCDMS SNOLAB塔，并在大学测试设施的小型设备上进行支持测量。由此产生的数据将允许能量标度校准，背景水平的测量，详细的声子和电子物理的探测器的理解，改进的背景拒绝技术的发展，验证和调整探测器蒙特卡罗，和优化的SuperCDMS SNOLAB操作参数。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。

Observations indicate that 85% of the matter in the Universe is not made of normal atoms but must be otherwise undetected elementary "dark matter" particles that do not emit or absorb light. Remarkably, particle physics theories proposed for other reasons predict the existence of Weakly Interacting Massive Particles (WIMPs) with just the right properties to be this dark matter. If WIMPs are the dark matter, they may be detectable when they scatter in Earth-based detectors. Direct detection of WIMP dark matter would solve a fundamental mystery in particle physics and cosmology, providing a unique window to learning about the primary matter constituents of the Universe and of physics beyond the Standard Model of particle physics. Over the past three years, the SuperCDMS collaboration has led the field in the search for low-mass dark matter. The most recent results from CDMSlite reached an energy threshold for electron recoils as low as 56 eV. These results excluded new parameter space for the dark matter-nucleon spin-independent cross section for dark matter masses between 1.6 and 5.5 GeV/c2. This project will focus on better understanding the response of the signal detectors in a push to make the SuperCDMS yet more sensitive.The SuperCDMS SNOLAB experiment will have a broad impact which extends beyond the search for dark matter. The experiment's phonon-mediated detectors have applications in cosmology, astronomy and industry. This effort will contribute opportunities for training of undergraduate and graduate students and postdoctoral researchers. SuperCDMS will engage in education and outreach at local institutions and will coordinate outreach at SNOLAB and the Sanford Underground Research Facility (SURF) in South Dakota to increase the broader impact with a focus on secondary education. This award will support participating in SNOLAB-hosted teacher workshops, modifying and providing middle school dark matter education modules to U.S. educators, and maintaining SuperCDMS-related outreach materials for SNOLAB in Canada and SURF. Existing alliances will enable out-reach to Sudbury First Nations communities. This effort will also support post-graduate education and outreach to underrepresented groups.In order to maximize the science output of SuperCDMS SNOLAB, detailed understanding of the response of detectors to potential signals and backgrounds is required. Measurements at two underground facilities (NEXUS at Fermilab and CUTE at SNOLAB) will characterize and calibrate pre-production SuperCDMS SNOLAB detectors and the first production SuperCDMS SNOLAB towers, with supporting measurements from small devices at university test facilities. Resulting data will allow energy scale calibration, measurements of background levels, understanding of the detailed phonon and electron physics of the detectors, development of improved background-rejection techniques, validation and tuning of Detector Monte Carlo, and optimization of SuperCDMS SNOLAB operational parameters. These data should also provide a dark matter search with world-leading sensitivity.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.