Search for Dark Matter with Xenon-based Technology

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。该奖项将资助一个以寻找暗物质为中心的综合研究和教育项目。与当地一所少数民族公立高中和阿德勒天文馆的合作，将通过定期的课堂参观、实地考察、指导、教师沉浸式体验和博物馆内的节目，真正地让学生、教育工作者和更广泛的公众参与暗物质的奥秘和当前的研究现状。这将产生深远而广泛的影响，直接影响到教师、天文馆工作人员、数百名URM学生和数千名博物馆游客（间接影响数十万人）。该研究项目为培养本科生和研究生提供了极好的机会，使他们成为基础科学前沿项目的一部分。该合同将允许PI为XENON1T做出贡献，XENON1T是一个直接探测WIMP的实验，部署在意大利亚平宁山脉下的Gran Sasso实验室（LNGS），在探测器的组装、调试和早期操作中，计划于2015年夏天进行。PI还计划开发精细的分析策略，以期提高XENON1T中利用的电离/闪烁识别方法的性能，以抑制主导的ã/ <e:2>背景。为了实现这一目标，PI将使用小型氙探测器进行一系列专门的测量，该探测器旨在收集核和电子反冲的纯样本。这将允许一个详尽的研究电离和闪烁过程，控制低能相互作用的液体氙。这些数据不容易直接从XENON1T中提取，然后将通过改进校准和抑制背景来提高对wimp的灵敏度。

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 will fund an integrated research and educational program centered on the search for dark matter. Partnerships with a local minority public high school and the Adler Planetarium will genuinely engage students, educators, and the broader public in the mystery of dark matter and the status of current research, via regular classroom visits, field trips, mentoring, teacher immersion experiences, and in-the-museum programming. This will have a deep and broad impact, directly reaching teachers, planetarium staff, hundreds of URM students, and thousands of museum visitors (hundreds of thousands indirectly). The research program offers excellent opportunities for training undergraduate and graduate students, making them part of a cutting edge project in fundamental science.This award will allow the PI to contribute to XENON1T, a direct detection WIMP experiment deployed at the Gran Sasso laboratory built underneath the Apennine Mountains in Italy (LNGS), in the assembly, commissioning and early operations of the detector, scheduled for summer 2015. The PI also plans to develop refined analysis strategies which are expected to enhance the performance of the ionization/scintillation identification methods that are exploited in XENON1T to suppress the dominant ã/â background. To achieve this goal, the PI will make a series of dedicated measurements with a small-scale xenon detector designed to collect pure samples of nuclear and electron recoils. This will permit an exhaustive investigation of the ionization and scintillation processes that govern low-energy interactions in liquid xenon. These data, which are not easily extractable from XENON1T directly, will then be used to increase the sensitivity to WIMPs through improvements in the calibration and rejection of backgrounds.