Cosmic antihelium-3 nuclei sensitivity of the GAPS experiment

Abstract

The General Antiparticle Spectrometer (GAPS) is an Antarctic balloon experiment designed for low-energy (0.1$-$0.3 GeV/$n$) cosmic antinuclei as signatures of dark matter annihilation or decay. GAPS is optimized to detect low-energy antideuterons, as well as to provide unprecedented sensitivity to low-energy antiprotons and antihelium nuclei. The novel GAPS antiparticle detection technique, based on the formation, decay, and annihilation of exotic atoms, provides greater identification power for these low-energy antinuclei than previous magnetic spectrometer experiments. This work reports the sensitivity of GAPS to detect antihelium-3 nuclei, based on full instrument simulation, event reconstruction, and realistic atmospheric influence simulations. The report of antihelium nuclei candidate events by AMS-02 has generated considerable interest in antihelium nuclei as probes of dark matter and other beyond the Standard Model theories. GAPS is in a unique position to detect or set upper limits on the cosmic antihelium nuclei flux in an energy range that is essentially free of astrophysical background. In three 35-day long-duration balloon flights, GAPS will be sensitive to an antihelium flux on the level of $1.3_{-1.2}^{+4.5}\cdot 10^{-6}{\mathrm{m}}^{-2}\mathrm{s}{\mathrm{r}}^{-1}{\mathrm{s}}^{-1}(\mathrm{GeV}/n{)}^{-1}$ (95% confidence level) in the energy range of 0.11$-$0.3 GeV/$n$, opening a new window on rare cosmic physics.

Accepted for publication at Astroparticle Physics, 13 pages, 5 figures

References in corpus (4)

• Antideuteron fluxes from dark matter annihilation in diffusion models
• Scrutinizing the evidence for dark matter in cosmic-ray antiprotons
• Large-scale Simulations of Antihelium Production in Cosmic-ray Interactions
• Passivation of Si(Li) detectors operated above cryogenic temperatures for space-based applications

Cited by in corpus (6)

• The ALICE experiment: a journey through QCD
• Reevaluation of the cosmic antideuteron flux from cosmic-ray interactions and from exotic sources
• Sensitivity of the GAPS Experiment to Low-energy Cosmic-ray Antiprotons
• The antinucleus annihilation reconstruction algorithm of the GAPS experiment
• Large-scale detector testing for the GAPS Si(Li) Tracker
• Antihelium-3 Sensitivity for the GRAMS Experiment