Estimating the performance of the GAPS detector with muon ground testing data from Antarctica

The General Antiparticle Spectrometer (GAPS) is a balloon-borne indirect dark matter experiment that was commissioned in Antarctica for the December 24/January 25 launch season. Its primary science goal is the search for light antinuclei in cosmic rays at kinetic energies below 0.25 GeV/n. This energy region is of particular interest for dark matter searches and remains largely unexplored. GAPS promises to yield unprecedented sensitivity for low-energy antideuterons, will measure the low-energy antiproton spectrum with high precision, and will open new discovery space for antihelium. To reach the required sensitivity, the GAPS detector incorporates a new approach for antimatter detection, utilizing a tracker with custom-designed, lithium-drifted Silicon detectors that both capture an incoming antinucleus into an exotic atom and measure the de-excitation X-ray and nuclear annihilation product, together with a fast time-of-flight system, allowing for a high-precision β measurement and trigger. During the past Antarctic season, GAPS performed a pre-flight, instrument testing campaign on the ground. Unfortunately, GAPS was not able to launch in the past season due to the weather. This talk will highlight key results from the Antarctic ground testing campaign and present an outlook for the December 2025/January 2026 Antarctic launch season in which GAPS is scheduled to launch.