BESS-Polar Experiment : Precise Measurement of Cosmic-ray Antiprotons by Long Duration Flights in Antarctica

A long-duration balloon flight in Antarctica, BESS-Polar experiment, is being pre- pared. It aims at extremely sensitive measurement of low energy antiprotons to search for any novel primary origin and to study the cosmic-ray propagation and the solar modulation. The search for cosmic antimatter such as anti-helium is a fundamental objective to study baryon asymmetry/symmetry in the Universe. This report describes the progress and future prospect of BESS-Polar experiment.