Mengjiao Xiao

In Search of Cosmic-Ray Antinuclei from Dark Matter with the GAPS Experiment

Abstract:
The origin of dark matter is a driving question of modern physics. Finding dark matter in the laboratory and elucidating its properties could revolutionize our understanding of the fundamental building blocks of the universe. The common challenges for dark matter searches in astrophysical signatures are large and uncertain backgrounds. The General Antiparticle Spectrometer (GAPS) is a balloon-borne experiment designed to identify low-energy cosmic antinuclei, in particular, antideuterons from dark matter annihilation or decay. With a novel detection approach that uses the uniquely characterized atomic X-rays and charged particles from the decay of exotic atoms, GAPS is sensitive to antideuterons and even antihelium with kinetic energy ≤0.25 GeV/n, which should offer an essentially background-free region to probe many generic dark matter models. Additionally, GAPS will collect a high-statistics antiproton spectrum in an unexplored energy range.

The GAPS instrument consists of a tracker of >1000 custom Si(Li) detectors; a precision-timing, large-acceptance time-of-flight system; and a novel oscillating heat pipe thermal system. GAPS is currently under integration and preparing for the first Antarctic balloon flight in late 2023, while two follow-up flights are planned. This talk will present the scientific impact of the GAPS experiment; its custom-developed instrument technology, including the design principle, commissioning of the GAPS functional prototype, and integration and testing of GAPS full payload, with a special focus on the construction of the Si(Li) tracker; and the path towards the initial flight.