An Alternative Explanation of the Varying Boron-to-carbon Ratio in Galactic Cosmic Rays

It is suggested that the decline with energy of the boron-to-carbon abundance ratio in Galactic cosmic rays is due, in part, to a correlation between the maximum energy attainable by shock acceleration in a given region of the Galactic disk and the grammage traversed before escape. In this case the energy dependence of the escape rate from the Galaxy may be less than previously thought and the spectrum of antiprotons becomes easier to understand.