Cosmic ray antiproton spectrum measured by BESS in 1993–1995

Abstract Balloon-borne experiments using a superconducting spectrometer were carried out successfully in northern Canada, in summer 1993 to 1995. In '93 flight, seven antiprotons were detected in the kinetic range between 200 and 600 MeV. The corresponding cosmic ray antiproton flux at the top of the atmosphere is found to be 6.4 −3.5 +5.5 ×10 −3 (m 2 sr s GeV) −1 . In '95 flight, improvement on the TOF resolution resulted to the observation of the forty antiprotons in the kinetic energy region 175 MeV to 1.3 GeV. The analysis on '95 flight is under way.