RUI: Collaborative Research: Improved Limits from DRIFT and R&D Towards Improved Directionality and Sensitivity

在这个精密宇宙学的时代，测量表明，普通物质只占宇宙总物质密度的一小部分。其余的，我们只能通过引力才能看到它的影响，它的性质是未知的，被称为暗物质。粒子物理模型表明，暗物质是由大爆炸遗留下来的弱相互作用大质量粒子组成的。如果WIMP是暗物质，那么它们在我们银河系中的存在可能是通过位于地下深处的探测器中原子核的散射来检测到的，以帮助排除宇宙射线的背景。由于预测的小相互作用概率和模拟预期信号的背景的存在，探测WIMP的实验努力极具挑战性。幸运的是，存在一些独特的暗物质信号，可以用来区分背景并决定性地识别WIMP相互作用。最大和最强大的特征是预测的WIMP通量对穿过银河系的太阳-地球速度的依赖，产生了实验室中核反冲方向的恒星调制。从径迹识别(漂移)暗物质的定向反冲识别实验是定向暗物质探测领域的领先者，它对WIMP诱导的核反冲的强大角度特征非常敏感。该奖项的学术价值在于，漂移的强大能力被用来解决当今科学中最重要的问题之一。这一合作将在西方学院测试他们的下一个原型探测器--漂移-IIe。它具有固有的可扩展设计，包括重新设计的场笼、质构化薄膜阴极、新的透明线读取器(每次读出的基准体积翻了一番)以及新的每根线数据采集系统(允许探测器平面中的低噪声和可信化)。漂移能力的潜力在国土安全和双贝塔衰变实验中有很好的应用前景。这项工作的更广泛影响还包括在越来越罕见的小规模实验中培训不同的本科生和研究生(包括代表性不足的少数群体)，使他们接触到广泛的研究经验。

In this era of precision cosmology, measurements suggest that ordinary matter represents only a fraction of the total matter density in the Universe. The rest, whose effect we can see only gravitationally, is unknown in its nature and is termed Dark Matter. Particle physics models suggest that dark matter is composed of relic Weakly Interacting Massive Particles, or WIMPs, left over from 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. Experimental efforts to detect WIMPs are extremely challenging due to the predicted small interaction probabilities and the existence of backgrounds that mimic the expected signal. Fortunately, a number of unique dark matter signatures exist that can be used to discriminate against backgrounds and decisively identify WIMP interactions. The largest and most robust signature is the predicted dependence of the WIMP flux on the Sun-Earth velocity through the Galaxy, yielding a sidereal modulation of the nuclear recoil direction in the laboratory. The Directional Recoil Identification From Tracks (DRIFT) dark matter experiment is a leader in the field of directional dark matter detection, with sensitivity to the powerful angular signature of nuclear recoils induced by WIMPs. The intellectual merit of this award resides in DRIFT's powerful capabilities being brought to bear on one of the most important questions in science today. The collaboration will be testing their next prototype detector, DRIFT-IIe, above ground at Occidental College. It features an inherently scalable design including a redesigned field cage, a texturized, thin-film cathode, a new, transparent wire readout which doubles the fiducial volume per readout, and a new every-wire data acquisition system which allows for lower noise and fiducialization in the detector plane. The potential of DRIFT's capabilities have promising applications to Homeland Security and double-beta decay experiments. Broader impacts of this work also include the training of a diverse set of undergraduate and graduate students (including underrepresented minorities) in increasingly rare small-scale experiments, giving them exposure to a wide range of research experience.