Introduction to a low-mass dark matter project, ALETHEIA: A Liquid hElium Time projection cHambEr In dArk matter

TL;DR

The paper introduces ALETHEIA, a liquid helium TPC detector designed to explore low-mass WIMP dark matter, emphasizing its low background and recent progress since 2020.

Contribution

It presents the design and development progress of ALETHEIA, a novel low-mass dark matter detector using liquid helium and TPC technology.

Findings

Conceptual design of ALETHEIA detector.

Initial progress since 2020.

Potential for low-background dark matter detection.

Abstract

Dark Matter (DM) is one of the most critical questions to be understood and answered in fundamental physics today. Plenty of astronomical and cosmological observations have already pinned down that DM exists in the Universe, the Milky Way, and the Solar System. However, understanding DM with 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. WIMPs is the most discussed DM candidate. After decades of hunting, a convincing WIMPs signal is still at large. 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$^2$). By filling the arguably cleanest bulk material, LHe, into the arguably most competitive detector in the field, TPCs, ALETHEIA is supposed to achieve an extremely low-level background; therefore, to help answer one of the most pressing physical questions today: the nature of DM. In this paper, we briefly go through the physics motivation of low-mass DM, the ALETHEIA detector's design, possible analysis channels available for DM searches, and the progress we have made since the project launched in the summer of 2020.