Field Rose Rogers (MIT) “The GAPS Antarctic Balloon Experiment: Low-energy Antinuclei for Dark Matter Detection”

Despite overwhelming evidence of abundant dark matter in the Universe, the nature of this material remains a mystery. The General Antiparticle Spectrometer (GAPS) is an upcoming NASA Antarctic balloon mission to search for signatures of dark matter annihilation or decay in the fluxes of low-energy (<0.25 GeV/n) cosmic antinuclei. GAPS will produce a precision cosmic antiproton spectrum extending to an unexplored low-energy regime, with sensitivity to light dark matter models, primordial black holes, and cosmic-ray propagation. GAPS will also either provide the first unambiguous detection of a cosmic-ray antideuteron or exclude the viable dark matter models that predict a low-energy antideuteron flux orders of magnitude above the astrophysical background. To identify these rare low-energy antinuclei while rejecting the abundant positive- nucleus backgrounds, GAPS pioneers a novel exotic atom-based particle identification technique, which relies on a system of >10 m2 of large-area high-temperature lithium-drifted silicon (Si(Li)) detectors. I will discuss the GAPS science program, with a special emphasis on the exotic atom method of particle identification and the Si(Li) detectors that are central to its success.