Astroparticle Detection

暗物质的发现对宇宙学、天体物理学和基本粒子物理学都具有根本性的意义。从银河系到宇宙尺度的广泛观测表明，宇宙中近90%的物质是由某种不同于普通物质的新型粒子组成的。这种物质只有通过引力才能显现出来，被称为“暗物质”，因为它既不发射光，也不吸收光。一个主要的假设是暗物质是由弱相互作用大质量粒子（wimp）组成的，这些粒子是在大爆炸后不久由普通物质湮灭产生的。如果wimp是暗物质，那么它们将在银河系周围形成一个球形晕，并通过与原子核的相互作用在一个适当的质量和敏感的探测器上被探测到。该奖项将通过支持LUX（大型地下氙）暗物质实验的工作来进一步寻找wimp， LUX（大型地下氙）暗物质实验目前正在南达科他州桑福德地下研究设施的Homestake矿山进行。该合同还将支持后续LZ （LUX-Zeplin）实验的发展，计划质量为7吨。对暗物质的探索一直是由具有超低放射性背景的辐射探测器的发展推动的。这些探测器也在中微子物理学中发挥着作用，并具有安全、医疗和工业应用的潜力。LUX和LZ的工作为学生提供了极好的和独特的技术技能培训机会，这些技能可以用于基础研究或私营部门的职业生涯。利用250公斤的主动监测液态氙，LUX实验现在是寻找暗物质的先锋。目前由LUX建立的wimp与普通物质之间相互作用速率的上限排除了参数空间的新区域，并提供了确凿的证据，证明在10 GeV左右的低质量区域中存在wimp可能是由于仪器效应或不明背景。随着未来几年的运行和分析，在LUX中是否会检测到wimp或设置新的上限将变得清晰。在任何一种情况下，LZ都可以很好地跟踪并继续搜索，其灵敏度比LUX目前的极限高1000倍。

The discovery of dark matter is of fundamental importance to cosmology, astrophysics and elementary particle physics. A broad range of observations from galactic to cosmological scales indicate that nearly 90% of the matter in the universe is made up of some new type of particle, different from ordinary matter. This type of matter has revealed itself only through gravity and is referred to as "dark matter" because it neither emits nor absorbs light. A leading hypothesis is that the dark matter is comprised of Weakly Interacting Massive Particles, or WIMPs, that were produced shortly after the Big Bang from annihilation of ordinary matter. If WIMPs are the dark matter then they will make up a spherical halo around the Milky Way and be detectable through interactions with atomic nuclei in a suitably massive and sensitive detector. This award will further the search for WIMPs by supporting work on the LUX (Large Underground Xenon) dark matter experiment that is currently operating in the Homestake Mine in the Sanford Underground Research Facility in South Dakota. This award will also support development of the followup LZ (LUX-Zeplin) experiment, with a proposed mass of seven tons. The search for dark matter has been driven by the development of radiation detectors with ultra-low radioactive backgrounds. These detectors are also playing a role in neutrino physics, and have the potential for security, medical and industrial applications. Work on LUX and LZ provides excellent and unique opportunities for student training with technical skills that can be used in careers in basic research or in the private sector. Using 250 kg of actively monitored liquid xenon, the LUX experiment is now at the vanguard in the search for dark matter. The upper limit on the interaction rate between WIMPs and ordinary matter that is now established by LUX rules out new regions of parameter space, and provides solid evidence that claims of WIMPs in the low mass region around 10 GeV are likely due to instrumental effects or unidentified backgrounds. With the next few years of operations and analysis it will become clear whether WIMPs will be detected in LUX or new upper limits set. In either case, LZ will be well positioned to follow up and continue the search with sensitivities 1000 times better than LUX's current limit.