标题： ALETHEIA：使用液氦TPC探测低质量暗物质 显示英文标题

标题： ALETHEIA: Hunting for Low-mass Dark Matter with Liquid Helium TPCs

摘要： 暗物质（DM）是当今基础物理中最为关键的问题之一，需要被理解和回答。 各种天文学和宇宙学技术的观测强烈表明，DM存在于宇宙、银河系和太阳系中。 然而，在基本物理的语言下理解DM仍在进行中。 DM直接探测测试银河系DM粒子与地下探测器核子之间的相互作用截面。 尽管弱相互作用大质量粒子（WIMPs）是最受讨论的DM候选者，但最令人信服的实验在该领域一致得出了无WIMPs的结论。 相比之下，低质量WIMPs区域（$\sim$10 MeV/c$^2$- 10 GeV/c$^2$）相较于高质量WIMPs（$\sim$10 GeV/c$^2$- 10 TeV/c$^2$）尚未被充分探索。 ALETHEIA（A Liquid hElium Time projection cHambEr In dArk matter）实验旨在利用充满液氦的TPCs（时间投影室）寻找低质量WIMPs。 在本文中，我们回顾了该项目的物理动机、探测器的设计、研发计划以及自2020年夏季项目启动以来所取得的进展。 显示英文摘要

摘要： Dark Matter (DM) is one of the most critical questions to be understood and answered in fundamental physics today. Observations with varied astronomical and cosmological technologies strongly indicated that DM exists in the Universe, the Milky Way, and the Solar System. Nevertheless, understanding DM under the language of elementary physics is still in progress. DM direct detection tests the interactive cross-section between galactic DM particles and an underground detector's nucleons. Although Weakly Interactive Massive Particles (WIMPs) are the most discussed DM candidates, the null-WIMPs conclusion has been consistently addressed by the most convincing experiments in the field. Relatively, the low-mass WIMPs region ($\sim$ 10 MeV/c$^2$ - 10 GeV/c$^2$) has not been fully exploited compared to high-mass WIMPs ($\sim$ 10 GeV/c$^2$ - 10 TeV/c$^2$). The ALETHEIA (A Liquid hElium Time projection cHambEr In dArk matter) experiment aims to hunt for low-mass WIMPs with liquid helium-filled TPCs (Time Projection Chambers). In this paper, we go through the physics motivation of the project, the detector's design, the R\&D plan, and the progress we have made since the project has been launched in the summer of 2020.