Results from BESS-polar i 2004 Antarctica flight

The Search for antimatter in the galactic cosmic radiation is one of the main scientific objectives of the Balloon-borne Experiment with a Superconducting Spectrometer (BESS). A flatter antiproton spectrum below the secondary production peak at 2 GeV might suggest possible novel antiproton sources, such as evaporating black-holes or decaying super symmetric particles. The BESS-Polar experiment is designed as a highly transparent magnetic rigidity spectrometer that can precisely detect antiprotons down to energies of 0.1 GeV were a potential excess of primary antiprotons over the secondary production might be more apparent. The BESS-Polar instrument had its first successful balloon flight in December 2004, from McMurdo Station in Antarctica. During the 8.5-day long flight 900 million events were recorded. In this paper, we report antiproton and proton spectra as well as the search for antihelium.