The nature of Dark Matter (DM) is one of the most pressing questions to be answered in fundamental physics today. Observational evidence based on astronomy telescopes of many kinds has consistently pointed to the existence of DM, while the experiments aiming at understanding DM’s particle physics characters have returned no positive results so far. Thanks to several advantages, underground direct detection is probably the most efficient detecting strategy compared to indirect detection and the searches at the colliders. However, no convincing DM signals have been observed from underground experiments yet, after nearly a half-century of hunting.
ALETHEIA (A Liquid hElium Time projection cHambEr In dArk matter) is a low-mass DM direct detection project, filling TPCs (Time Projection Chamber) with 4 K liquid helium-4. Since TPC is arguably the best technology in DM direct hunting, and liquid helium is arguably the cleanest bulk material, we, therefore, believe the ALETHEIA detector could achieve an instrumental background-free search, no matter ER (Electron Recoil) or NR (Nuclear Recoil) backgrounds. Such a unique feature (a) enables exploring many DM models including but not limited to the WIMPs one, (b) has the potential of claiming a discovery thanks to the especially low backgrounds, and (c) has ever demonstrated by any DM experiments before worldwide according to our understanding. However, since nobody has built an LHe TPC before, much R&D is required to demonstrate the detector’s functionality. After working on the project for three years, we demonstrated some of them, though more to be done.
About the speaker:
Dr. Liao holds an assistant professor equivalent position at CIAE (China Institute of Atomic Energy) and is a visiting scientist at Brown University in the US. He has worked on three DM direct detection projects since 2013: DAMIC, LUX/LZ, and ALETHEIA. Before that, he worked in the CMS experiment for four years at CERN and 4 years in the CSNS project at IHEP with privilege.
Dr. Liao received his Ph.D. in particle physics from the University of Zurich, Switzerland, in 2016. After that, he worked as a postdoc and senior scientist for two years at Brown University. He returned to China in the summer of 2019.
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