2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/211219The BESS-Polar spectrometer had its first successful balloon flight over Antarctica in December 2004. During the 8.5-day long-duration flight, almost 0.9 billion events were recorded and 1,520 antiprotons were detected in the energy range 0.1-4.2 GeV. In this paper, we report the antiproton spectrum obtained, discuss the origin of cosmic-ray antiprotons, and use antiprotons to probe the effect of charge sign dependent drift in the solar modulation.18 pages, 1 table, 5 figures, submitted to Physics Letters BAstrophysicstext