Speaker
Description
The nature of dark matter remains one of the most pressing mysteries in modern physics. Efforts to probe this mystery using cosmic signals have been hampered by large and uncertain astrophysical backgrounds across many detection channels. More than 25 years ago, low-energy (kinetic energy $\lesssim1\,$GeV/n) cosmic-ray antideuterons ($\overline{\mathrm{d}}$) were proposed as a unique dark-matter signature because their astrophysical production is strongly suppressed in this regime. The expected dark-matter $\overline{\mathrm{d}}$ flux is approximately nine orders of magnitude smaller than the cosmic proton flux in the relevant energy range, which has until now prevented sufficiently sensitive searches.
The General Antiparticle Spectrometer (GAPS) is designed to address these challenges and achieve sensitivity to the expected dark-matter $\overline{\mathrm{d}}$ signal. GAPS will also deliver leading sensitivity to low-energy cosmic-ray $\overline{\mathrm{p}}$ and $\overline{\mathrm{He}}$. It achieves the large acceptance and rejection power required for a rare event search by employing a novel detection technique based on the formation, de-excitation, and annihilation of antinucleonic exotic atoms. On December 16th, 2025, the GAPS instrument was launched on its first (of several) long-duration Antarctic balloon flight and observed cosmic-rays for 25 days. I will describe the GAPS instrument design, the exotic atom detection technique, and present preliminary results from ground calibrations and flight.