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

在这个精确宇宙学的时代，测量表明，普通物质只占宇宙总物质密度的一小部分。其余的物质，其作用我们只能在引力作用下看到，其性质是未知的，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（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。由于预测的相互作用概率很小，并且存在模拟预期信号的背景，因此检测wimp的实验工作极具挑战性。幸运的是，存在许多独特的暗物质特征，可以用来区分背景，并果断地识别WIMP相互作用。最大和最强大的特征是预测WIMP通量与穿过银河系的太阳-地球速度的依赖关系，在实验室中产生了核反冲方向的恒星调制。轨道定向反冲识别（DRIFT）暗物质实验在定向暗物质探测领域处于领先地位，对wimp引起的核反冲的强大角度特征非常敏感。这个奖项的知识价值在于，DRIFT的强大能力被用于解决当今科学中最重要的问题之一。他们将在西方学院的地面上测试他们的下一个原型探测器DRIFT-IIe。它具有固有的可扩展设计，包括重新设计的现场笼，纹理化的薄膜阴极，一个新的透明导线读出器，每次读出的基准体积增加一倍，以及一个新的每线数据采集系统，可以降低探测器平面的噪声和基准化。DRIFT的潜力在国土安全和双β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各种各样的本科生和研究生（包括代表性不足的少数民族），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.