Precise Measurement of Cosmic‐Ray Proton and Helium Spectra with the BESS SpectrometerT. Sanuki, M. Motoki, H. Matsumoto et al.|The Astrophysical Journal|2000 We report cosmic-ray proton and helium spectra in energy ranges of 1 to 120GeV and 1 to 54 GeV/nucleon, respectively, measured by a balloon flight of theBESS spectrometer in 1998. The magnetic-rigidity of the cosmic-rays wasreliably determined by highly precise measurement of the circular track in auniform solenoidal magnetic field of 1 Tesla. Those spectra were determinedwithin overall uncertainties of +-5 0.000000or protons and +- 10 0.000000or helium nucleiincluding statistical and systematic errors.
Precision Measurement of Cosmic-Ray Antiproton SpectrumS. Orito, T. Maeno, H. Matsunaga et al.|Physical Review Letters|2000 The energy spectrum of cosmic-ray antiprotons ( &pmacr;'s) has been measured in the range 0.18-3.56 GeV, based on 458 &pmacr;'s collected by BESS in a recent solar-minimum period. We have detected for the first time a characteristic peak at 2 GeV of &pmacr;'s originating from cosmic-ray interactions with the interstellar gas. The peak spectrum is reproduced by theoretical calculations, implying that the propagation models are basically correct and that different cosmic-ray species undergo a universal propagation. Future BESS data with still higher statistics will allow us to study the solar modulation and the propagation in detail and to search for primary &pmacr; components.
Direct Observation of Sequential Weak Decay of a Double HypernucleusS. Aoki, S. Y. Bahk, K.S. Chung et al.|Progress of Theoretical Physics|1991 We have studied stars in nuclear emulsion due to the capture at rest of the Ξ- hyperons produced in the (<it>K</it>-, <it>K</it>+) reaction. The sequential weak decay of a double hypernucleus (nucleus with <it>S</it> = -2) has been directly observed. The double hypernucleus is assigned as either 10<inf>ΛΛ</inf>Be or 13<inf>ΛΛ</inf>B. This assignment excludes the existence of the <it>H</it> dibaryon lighter than 2203.7 ±0.7 MeV/c2.
Measurements of primary and atmospheric cosmic-ray spectra with the BESS-TeV spectrometerS. Haino, T. Sanuki, K. Abe et al.|Physics Letters B|2004 Primary and atmospheric cosmic-ray spectra were precisely measured with the BESS-TeV spectrometer. The spectrometer was upgraded from BESS-98 to achieve seven times higher resolution in momentum measurement. We report absolute fluxes of primary protons and helium nuclei in the energy ranges, 1–540 GeV and 1–250 GeV/n, respectively, and absolute flux of atmospheric muons in the momentum range 0.6–400 GeV/c.
Measurements of 0.2–20GeV/n cosmic-ray proton and helium spectra from 1997 through 2002 with the BESS spectrometerY. Shikaze, S. Haino, K. Abe et al.|Astroparticle Physics|2007