Development of the GAPS Experiment for Cosmic-ray Antinuclei Measurements*

The GAPS experiment is designed to carry out a dark matter search by measuring low-energy cosmic-ray antinuclei (antiprotons, antideuterons, antihelium) with a novel detection approach. For the case of antiprotons, a high-statistics measurement in the unexplored low-energy range will be conducted. In contrast, not a single cosmic antideuteron has been detected by any experiment, but well-motivated theories beyond the standard model of particle physics contain viable dark matter candidates, which could lead to a significant enhancement of the antideuteron flux due to annihilation of dark matter particles. This flux contribution is calculated to be especially large at low energies, which leads to a high discovery potential for GAPS. The theoretically predicted antideuteron flux resulting from secondary interactions of primary cosmic rays, e.g. protons, with the interstellar medium is very low. Furthermore, the search for antihelium-3 and antihelium-4 promises an even lower secondary background. As the cosmic-ray experiment AMS-02 has recently identified a few antihelium candidates in their higher-energy data, it is crucial to perform an independent search with a different experimental technique in a lower energy range. GAPS is designed to achieve its goals via a series of long duration balloon flights at high altitude in Antarctica starting from 2020.

The presentation will review the theoretical status, introduce the GAPS experiment, and report on the status of the different GAPS subdetectors as well as on the development of the simulation and analysis tools.