Collaborative Research: Continuation of the Dark Matter Search with XENON1T at LNGS

多次天文观测已经确定，宇宙中大约85%的物质不是由正常的原子组成的，而是由不发射或吸收光的未被探测到的基本“暗物质”粒子组成的。破译这种所谓的暗物质的本质对宇宙学、天体物理学和高能粒子物理学至关重要。一个主要的假设是，它是由大爆炸后瞬间产生的弱相互作用大质量粒子（wimp）组成的。如果wimp是暗物质，那么它们在我们星系中的存在可以通过位于地下深处的探测器的原子核散射来检测，以帮助排除宇宙射线造成的背景。直接探测WIMP暗物质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组成和粒子物理学标准模型之外的物理学提供一个独特的窗口。该奖项支持在格兰萨索国家实验室（LNGS）地下实验室参与XENON1T暗物质搜索项目的美国小组。氙气项目继续吸引着公众的想象力。例如，《生活大爆炸》等几部电视节目就证明了这一点，其中几部节目都有氙气的情节和结果。通过讲座和外展活动鼓励公众对科学的兴趣。XENON1T将在解决暗物质之谜方面发挥重要作用，要么探测wimp，要么将其作为可行的暗物质候选者施加巨大压力。为了解决这一基本的物理问题，这些奖项将吸引许多本科生、研究生和博士后研究人员，使他们接触到物理学和宇宙学的各种学科，并在最先进的技术方面进行培训，从而为成为该领域未来的领导者做好准备。最后，XENON中使用的仪器和技术与广泛的应用相关，从国土安全和医学成像领域到大型数据集的分析和统计处理。未来四年的计划将集中于XENON1T实验的持续运行及其科学数据分析。由130名科学家组成的国际氙合作项目继续由哥伦比亚大学的PI领导，美国成员在实验管理及其科学计划中发挥关键作用。XENON1T使用迄今为止建造的最大的液态氙时间投影室（TPC），有2吨的活性Xe目标，对暗物质弱相互作用大质量粒子（wimp）的灵敏度最高，对于40 GeV的弱相互作用大质量粒子，灵敏度为2 × 10^-47 cm^2。有了这项提议的资金支持，美国将在这个十年结束后的很长一段时间内保持对暗物质直接搜索的领先地位。

Multiple astronomical observations have established that about 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. Deciphering the nature of this so-called Dark Matter is of fundamental importance to cosmology, astrophysics, and high-energy particle physics. A leading hypothesis is that it is comprised of Weakly Interacting Massive Particles, or WIMPs, that were produced moments after the Big Bang. If WIMPs are the dark matter, then their presence in our galaxy may be detectable via scattering from atomic nuclei in detectors located deep underground to help reject backgrounds due to cosmic rays. 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 constituent of the Universe and of physics beyond the Standard Model of particle physics. This award supports the US groups involved in the XENON1T dark matter search program at the INFN Gran Sasso National Laboratory (LNGS) underground laboratory.The XENON project continues to captivate the imagination of the public. This is evidenced, for example, by several TV shows such as "The Big Bang Theory", which on several occasions featured XENON plots and results. Public interest in science is encouraged through talks and outreach activities. XENON1T will play a significant role in solving the dark matter puzzle, by either detecting WIMPs, or putting them under immense pressure as viable dark matter candidates. In addressing this fundamental physics problem, these awards will engage many undergraduate and graduate students as well as post-doctoral researchers, exposing them to a variety of subjects in physics and cosmology, and training them in state-of-the-art technologies, thus preparing to become future leaders in the field. Finally, the instrumentation and techniques used in XENON are relevant to a wide range of applications, from areas in homeland security and medical imaging, to the analysis and statistical treatment of large data sets.The program for the next four years will focus on the continued operation of the XENON1T experiment and its science data analysis. The international XENON Collaboration of 130 scientists continues to be led by the PI at Columbia University with key roles served by US members both in the management of the experiment and its scientific program. XENON1T uses the largest liquid xenon time projection chamber (TPC) built to-date, with 2 tonnes active Xe target, and the highest sensitivity to dark matter Weakly Interacting Massive Particles (WIMPs), at the level of 2 × 10^-47 cm^2 for 40 GeV WIMPs. With funding of this proposal, the US will remain in the lead of the direct search for dark matter well beyond the end of the decade.