The GAPS experiment – a search for cosmic-ray antinuclei from dark matter

Abstract

The General Antiparticle Spectrometer (GAPS) is a balloon-borne experiment that aims to study low-energy cosmic-ray antinuclei. A novel detection concept that utilizes the physics of exotic atoms allows GAPS to realize a large sensitive area, a low energy threshold, and a high identification capability for antinuclei. The primary goal is to search for antideuterons in the energy region <0.25 GeV/n, where they are predicted to be backgroundfree probes for dark matter-annihilation or decay in the Galactic halo. GAPS will also measure precise low-energy antiproton spectra, which provide crucial information about the source and propagation of cosmic rays. Three flights on long-duration balloons from Antarctica are planned; the first flight of GAPS is scheduled for late 2021. This paper presents the scientific motivation, detection concept, development status, and plans for GAPS.